DET KONGELIGE DEPARTEMENT
FOR HANDEL, SJØFART, INDUSTRI, HANDVERK OG FISKERI
NORGES SVALBARD- OG ISHAVS-UNDERSØKELSER
LEDER: ADOLF HOEL
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Nr. 40
THE DOWNTONIAN AND DEVONIAN VERTEBRATES OF SPITSBERGEN
v
SU BORDER CYATHASPIDA
PART I TRIBE PORASPIDEl
FAMILY PORASPIDAE KlÆR
BY
JOHAN KIÆRt AND ANATOL HEINTZ
WITH I MAP,3 TAB L ES, 57 FIGU RES IN THE TEXT AND 40 PLATES
OSLO
I KOMMISJON HOS JACOB DYBWAD
1935
RESULTS OF T H E NORWEG I AN EXPP 1906-1926 PUBL I S HE D IN <.
(See Nr. 1 of this series.)
)NS TO SVA LBARD R SER IES
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K r i s t i a n i a (O s l o).
ISACH S E N , G U N N A R, Rapport sur I'Expedition Isachsen au Spitsberg. 1 9 1 2, No. 1 5.
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st i a n i a I 9 1 6.
As the result of the expeditions of ADOLF H O E L and ARVE STAXRUD 1 91 1 - 1 9 1 4 the following memoir has been published in V i d e n ska p s s e l ska p e t s Skr i ft e r. I. M a t .
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DET KON GELI GE DEPARTEMENT
FOR HANDEL, SJØFART, INDU STRI, HÅNDVERK O G FI SKERI
NORGES S VAL BARD- OG ISHAVS -UNDERSØKELSER
LEDER: ADOLF HOEL
SKRIFTER OM SVALBARD OG ISHAVET
Nr. 40
THE DOWNTONIAN AND DEVONIAN VERTEBRATES OF SPITSBERGEN
v
SUBORDER CYATHASPIDA
PART I
TRIBE PORASPIDEl
FAMILY PORASPIDAE KlÆR
BY
JOHAN KIÆRt A N D ANATOL HEINTZ
WITH l MAP, 3 TABLES, 57 FIGURES IN THE TEXT AND 40 PLATES
O S L O
[ KOMMISJON HOS JACOB DY BWAD
1935
A. W. BRØGGERS BOKTRYKKERI Als
CONTENTS
Page
Preface . . . . 5
I ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Collection of the m aterial (A. H . ) .. ... ... . .. . . .. . .. . . ... ..... . . .. . .. . . .. 8
The general stratigraphy of the fossi l i ferous part of the Red Bay Series (A . H . l. . 10
M ateri al and m ethods (A. H.) . . . ... . . .. . . . .. . . 17 Classification of the H e terostraci ( j . K. & A. H . l. . . . . . . . . . . . . . . . . . . . . . . . . . 1 9 H i storical review o f the Cyathaspida . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Sub Order Cyathaspida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 The termi n ology of the dermal skeIeton . . . . . . . . . .. .. . . ... 4 1 Tri be I . Poraspidei . . . 49
Family Poraspidae Kiær . . . . . . . . . . . . . . . . . .. 50
1 G e n us Poras pis Kiær . . . . . . . . . . . . . . . . 51
Speci fi c d e fi n ition . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Poraspis polaris Kiær . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59
Forma angusta. . . . . . . . . . . . . . . .. 61
Forma lata . . . . . . . . . . . . . . . . . . .. 75
Oth er portions of the derrnal ske leton ... ... . . ... 76
The forms of Porasp:s polaris from the other h ori zons of the upper part of the Frænkelryggen Group 76 Poraspis brevis n. sp. . . . . .. 78
Poraspi s i nterm edia n . sp. .. . . ... . . . . . .. 79
Poraspis subtilis n. sp. ... . ... . . ... .. ... .. . .... . . .. . 81
Poraspis elongata n . sp. . . . .. . . ...... ... . . . .. ..... 82
Poras pis rostrata n . sp. . . .... .. . . . . . . . 85
Poraspis cyl indrica n . sp. ... . . . . . . . . . . . . . . . . . 88
Poraspis magna n . sp . . .. . . ..... . . .. . .. . . . 92
Poraspi s sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 97
Poraspis sericea (Lan kester) .. . . ... . ... . . .. .. . . " 9 8 Poraspis barroisi (Le riche) . . . . . . . . . . . . . . . . . . . . . 10 1 Poraspisda from Podolia . . . 104
The body scale s and isolated plates i n Poraspis (A . H . ) . . " !O8 The total reconstructi on of the Poraspis (j . K. & A. H . ) .. . . 1 24 A retrospect of the evolution o f Genus Poraspis Kiær . . . . . 1 25 2 Genus H o m aspis H e i n tz n. n ... .... . .. .. ... . .. .. . ... ... . " 127 H omaspis nitidus ( K iær ) .. . . .. . .. . .. .. . ... . .. .. . . ... 128
Homaspis nitidus var. robustus n. var. ... .... .. . . 132
3 G e n u s Cryptaspis Brya nt . . . . . 132 B i bliography . . . • . . . " 134
PREFA CE
P
rofessor Dr. J o h a n Kiær, during the last had inten sively studied the fossil fishes collected by N o rwegia n 20 years of h i s li fe, expeditions t o Spitsberge n . H e h a d h oped to be a b l e t o describe t h e forms belonging to t h e group Heterostraci, a n d had planned to publish 3 or 4 monographs a bout these re m arka ble vertebrates. During his last years he concentrated h i s investigations on the fi rst group o f Heterostraci, which he called Cyathaspida. A m a n uscript of about 200 pages text, with m ore than 1 00 plates and 75 figures in the text, was written and h e had h oped to finish the whole work i n the autu m n o f 1 93 1 . Un fortu nately, a painful illness destroyed h is plans a n d preve n ted h i m fro m fi n i s h i n g his great work . After h i s d e a t h on October 3 1 s t , 1 93 1 , only a n u n fi n ished m a nuscript was fou n d .
As Professor Kiær's pupil, collaborator and friend, a n d as a specialist i n the paleozoie fishes, I have u ndertaken to fi n is h his paper on the Cyathaspida. A study of the m a nuscri pt has shown me that u n fortunately, only the system atical part, is m o re or less finished, the in troduction and the gen eral part not having been w ri tten a t all. But there has been so much to alter, com pare, add and correct i n the systematical part, that I have been una ble to get it ready quickly enough.
As, i n the meanti m e , i t was very desirable to publish the results o f Pro fessor Kiær's i n vestigations a s s o o n a s possible, I prepared, a fter consultation with Docent A . H oel, a sh ort a bstract fro m the system a tical part o f the m a n uscript, which abstract was published i n N ov e m ber
1 932. (Kiær 1 932, l).
I n a list o f contents fo und among Professor Ki ær's e ffects h e d i vides the paper i n to th ree parts : I) General a n d stratigraphical introduction, I l ) System atical part, classification of the Heterostraci and I l l ) General part (strueture and organization o f Cyathaspida, syste matical p osition of Cyathaspida and Heterostraci).
As mentioned, of these th ree parts only the second i s m ore or less ready written. Of the fi rst, on ly some s hort re marks a n d sketches h a v e been fou n d , while the m aterial for the third i s com pletely a bsent, except some few d rawings without explanations.
I have t h erefore d etermined to com plete as thoroughly as possible the fi rst and second parts, but not, in this publicatio n , to atte m pt to reconstruct Professor Kiær's opinion upon the syste m a tical position of the H eterostraci.
It has, h owever, proved d uring the prepa rati on of the ma nuscript, that it will be m o re practical not to publish the whole paper at once, but to divide i t i n to severaI pa rts. The first, which is presented h ere, includes the introductional part and the d escription of the Fam. Pora
spidae - the fi rst a n d largest fa m i ly o f t h e Tribe Poraspidei. I n the second, the oth er fa m i l ies belonging to the Tribe Poraspidei will be dealt with and, fi n ally, the third will contain the descri ption of the Tribe Cyathaspidei.
Paleontologisk M u seum , Oslo, May 1 935.
A. Heintz.
I NTRODU CTIO N
I n th e h uge m aterial of fish remains collected by N orwegia n expeditions fro m the Downtonian and Devonian formations o f S pits
bergen, the Heterostraci a re the m ost i m portant, particularly in the two oldest series pertaining to the Downtonian and the Lower Devonian . H ere i n certain h orizons the fossils are found i n e normous quantities and o f ten in a n excellent state o f p reservation ( Pl. 1) . T h ey also occur i n such considerable n u m bers o f partly known , partly new and richly varyi ng forms, that one m ight be tempted to consider these a rctic regions as being the very centre of distribution with regard to this remarkable grou p o f fishes.
I t is, with out doubt, the largest and best preserved m aterial o f the Heterostraci w h ich has ever been brought together. Un fortunately , m ost o f the forms here, as in previously known regions fro m m ore southern latitudes, h ave been fou n d only as isolated shields and scales.
Still the considerable n u m ber o f speei mens, which h ave enabled a thorough exa m i n ation, and a few particularly good fi n d s i n a m o re or l ess com plete state o f preservation , have m ad e it possible to get a better i n sight than before, into the structure of these su rely very prim itive vertebrates. The examination o f this enorm ous m aterial, containing m ore than s i x thousand rock pieces, each of ten with m a n y speei mens o f d i fferent forms, has necessarily taken a long time. In fact, it has cost the authors m a n y years work. And yet, i n this fi rst part there will be descri bed a few groups, n a m ed the Cyathaspida , o f the O rder o f the Heterostraci. These are forms related to the previously-known Genera Cyathaspis and Palaeaspis.
8 J O H A N K l Æ R A N D A N A T O L H E I N T Z
COLLECTIO N OF THE MATERIAL. (A. H.)!
The m aterial of the Heferostraci, descri bed i n this paper, has been collected exclusively in Red Bay, a small bay on N orth S pitsbergen . H ere we flnd the beds of Downtonian age. The mighty Red Bay Series begin s with congl o merate, continuing with yellow, red and green sand stones and shales. It m easures about 3 000 meters of which the u ppermost l SOO m contain a great quan tity of fossil s.
This series was discovered and explored by N o rwegian expeditions ( H oel 1 929, Vogt 1 926, 1 929) and all the enormous m aterial collected h ere, is now preserved i n the Paieo ntological Museu m i n Oslo.
The discovery o f the fossil-bearing st ra ta in Red Bay, was made i n 1 906 b y a n expedition fl tted out b y Prince Albert I of Mon aco and led b y G . I sachsen ( H oel 1 9 1 0) . O n a m ountain, called " Mt. Pteraspis" situ
ated between Liefde Bay and Red Bay, Lieutenant Staxru d , in a h orizon 800 m above sea-Ievel , collected some concreti ons containing fragments o f flshes. These fi rst fossils from Red Bay were determ ined b y Kiær as s peci m e n s o f a small Pteraspis an d fragments of a Cephalaspis (Kiær i n H oel's 1 9 1 0, 1 914, Kiær 1 9 1 6, Stensi6 1 927, H oel 1 929).
The next ex ploration of the st ra ta in Red Bay and coll ection of fossiIs were undertaken d u ring I sach sen's great expeditions in the su m m ers o f 1 909 a n d 1 9 1 0. In 1 909 Docent H oel system atically col
lected fossils o n Frænkelryggen and on Mt. Ben N evis, new localities d iscovered by him. The next s u m m e r H oel continued the collection o n Frænkel ryggen a n d G . Watnelie on Ben N evis. I n both these l ocalities m o re than 30 fossiliferous h o rizons containing a great n u m ber of fossiIs were fou n d and i m m ense collections o f these were brought home. This m ateria l com prises the n ucleus of the collection of the Down tonian fossils fro m Red Bay, preserved in Oslo, a n d is o f particular great value as i t consists o f fossils col lected in man y
l (A. H.) -after the title of the chapter i n dicates th at it i s w h olly written by A. H e i ntz.
(J. K. & A. H.) - after the title of the chapter indicates that more than a half has been written by A. H e i ntz.
CYAT H A S PI DA 9 exactly determined h orizo n s through practical ly the whole Red Bay Series, and thus gives the best material for a stratigraphical division o f this form ation . The next expeditions visiting the Red Bay Series, was H oel's and Staxrud's i n 1 911 a n d 1912. The m ost i m portant work these yea rs was d o ne round Wood Bay and Wijde Bay. The only collection in the Red Bay Series was gathered on Frænkelryggen by H oel and Holtedahl i n 1911 and around Mt. Pteraspis by H oe l in 1912.
During the succeeding 13 yea rs n o expeditions visited Red Bay, and not before 1 925 was a new collection made i n this interesting locality. The Spitsbergen ex peditions o f Professor Th. Vogt in 1 925 and 1 928 was in itiated by Vogt a n d planned a n d arra nged b y the Professors Kiær and Vogt. The expedition in 1 925 also received valuable help fro m H oel 's expedition to Spitsbergen that year. The special object of these two expeditions was a study of the Downtonian and Devonian formations of central and n orthern Spitsbergen .
I n 1 925 (Vogt 1 926) the expedition, with Dr. A. Heintz and Docent Fr. I sach sen as scientific mem bers , wo rked, as pl an ned , one week in Red Bay. The good finds, on this s h o rt vis it, involved a longer stay in this area next ti m e .
I n 1 928 (Vogt 1929) a party o f three paleontologists D r . A. Heintz, Dr. T. Strand and Dr. L. Størmer with one assistent - spent more than a m onth in Red Bay and undertook a s ystem atical collection o f fosslis fro m d i fferent localities . Frænkelryggen and Ben Nevis were very carefully explored and a n u m ber of new fossil localities Were found.
In addition, they also made some excu rsions to Mt. Wulff and col lected fossils on d i fferent sm aller ridges, moraines a n d on the shores of Red Bay.
T h e m aterial gathered by these two last expeditions was a very welcome addition to the older, col lected by H oel . It partly completed the material fro m older localities, and partly consisted of excel len tly preserved speci mens, s h owing not only the finest details in the structure o f the d orsal and ventrai shields, but also the structure of the hin d , scale-covered part o f the body.
As we h a ve seen, seven d i fferent N orwegian expeditions, have worked i n Red Bay ( 1 906, 1 909, 1 910, 1 911 , 19 1 2, 1 925 and 1 928) , (Table I ) . The m aterial o f fish fossiIs coll ected o n these exped itions is really enormous. About 6 000 rock pieces are now preserved in the m u seum in Oslo, many, contain ing a great num ber o f speei mens. The greatest part of this collection consists of d i fferent Heterostraci, o f Cephalaspida, already partl y described b y Sten si6 (1927), a n d , finally, o f Lammelibranchiata (partly described b y Quenstedt ( 1 926) ) , Ostracoda (described by Solle 1 935) Merostomata (described by Størmer, 1 934) and bad ly preserved plants.
Of the i m mense m aterial of Heterostraci, th ose belonging to the Fa m . Poraspidae Kiæ r (Su b-Order Cyathaspida) will be described in t h i s paper.
1 0 J O H A N KlÆR AN D A N ATOL H EINTZ
T a b l e I .
Expedi t i on Leader Col lectors Local i ties
1906 . .. . . . .. G . Isachsen Staxrud Mt. Pteraspis
1909 .... . . G. Isachsen Hoel Frænkelryggen
Mt. Ben Nevis
1 910 .. . . . .. . G . Isachsen Hoel Frænkel ryggen
Watnelie Mt. Ben Nevis
191 1 . .. . . Hoel and Hoel Frænkelryggen
Staxrud Holtedahl
191 2 .. . . Hoel and Hoel Mt. Pteraspi s
Staxrud
1925 .... . . Th . Vogt F. Isachsen Frænkelryggen
A. Heintz E shore of R. B.
Th. Vogt Mt. Ben Nevis
1 928 ... . . Th. Vogt A. Heintz Frænkelryggen
T. Strand E shore of R. B .
L. Størmer Mt. Ben Nevis
Mt. Wulff
THE GENERAL STRATIGRAPHY
OF THE FOSSILIFEROUS PART OF THE RED BAY SERIES .
(A. H.)
The description of the stratigraphy o f the Red Bay Series, will be given l ater by Professor Th. Vogt. i n his paper on the stratigra phy of the Devonian rocks i n Spitsbergen . In this pl ace, chiefly based on the previously published descriptions o f the stratigra phy of the Red Bay Series ( H oel 1 9 1 0, 1 9 1 4, 1 929 ; H o l tedahl , 1 9 1 3 , 1 9 1 4 , 1 926 ; Sten si6 1 927) , will only be given a su m m ary o f the stratigraphical division o f that part o f the Red Bay Series, where the greatest portion of the fossils has been collected . Such a description i s necessary for the u nderstanding of t h e relative stratigraph ical position of the d i fferent fossilbearing horizol1s mentioned later i n this paper. A m ap o f the innermost part of the east side of Red Bay (pag. 1 1 ) where the best fossil localities occu r, and a pan ora mie view o f the same part ( fig. l), s h ow the position of the d i fferen t l ocalities and horizons. The m ap, a some
what altered, enlarged copy of I saehsen ' s m aps of N W Spitsbergen, is worked out by H eintz and Størm er. The panoram a is based on a sketeh made by H eintz. The heigths on this panora m a are greatly enlarged , thus d isplaying a quite disti net relief.
Red Bay � I I Ill· GJ?artd ? .\liO 500 760 1fO m,. E<,j.utdist 50_ N ( «« S Explanation of the numbers as in fig. 1. Nr "9" placed between the Second and First Glacier, is meant to be nr."13".
() -< ;.. >-j ::r: ;.. [fl ::s ei ;..
1 2 J O H A N K l Æ R A N D A N ATHOL H E INTZ
And.,.,ee Glaeie,.
Fig. I. Pan oramic v i e w of a part of the east shore l. Psamm o3te us Horizon. 2. C orvaspis I-Ioriz o n . 3. Plant I-Iorizon . 4. Primaeva I-Iorizon. 5. Polaris Il. Cten aspi s I-Iorizo n . 12. B e n n e v i aspis I-Iorizo n . 1 3. Tunge. A-I I-Ioe l's
As is kn own, the oldest part of the fossil-bea ring deposits was found on Frænkel rygge n . A s the striking of the sandsto n e i n the Red Bay Series is a bout N N W-SSE with the d i p towards the west, it i s natural t h a t w e find the oldest deposits o n the top and north s i d e of Fræn kelryggen .
I n reality, the ol dest known fossil h orizon i s placed o n the very top of the ridge in a yellow-grey sandstone, about 550 m a bove sea
leve! . This horizon, which was discovered by Strand in 1 928, was called the " Psam m osteus horizon " as the m ost abundant fossil in the layer a re fragments of an i n teresting new Psammosieus-like for m .
The second h orizon, called t h e " Corvaspis" horizon , was discovered by H ei n tz in 1 928, on the north side of Frænkel ryggen . Here was found a large num ber o f big s h ield plates, covered by a rem arkable structu re, rem i n i scent of that in Tolypaspis. It is, of course, evident that the for m fro m Spitsbergen h as nothing to d o with the Esto nian ; i t is probably a Psammosieus-like for m . I t was recen tly descri bed b y Woodward ( 1 934) fro m England a s Corvaspis kingi.
The third horizon, was also fo und i n 1 928 b y Strand and Størmer, on the north side of Fræn kel ryggen , somewhat lower down than the Corvaspis h orizon . Here, i n addition to the fish fossils, was found a n u m ber o f badly-preserved plants, and the horizon i s therefore n amed the Plant horizon.
The fourth h o rizon , found in 1 909- 1 0 by H oel , is situated h igher up and m ore to the south nea rly at the edge o f Frænkelryggen . It was termed the " Pri maeva h orizon " after a small Pteraspis - Pi. prima eva
C Y A T H A SPIDA 1 3
, the Red Bay. A fter a sketch by A. Hei n tz.
orizon. 6. Angl aspi s Horizo n . 7. Red Horizon. 8. Rotundatus Horizon. 9. Cli ff. 10. V ogti Horizon.
ection . (Horizons from A to 1). J-U Hoel's Secti o n . (Horizons from J-U).
n . Sp. - found very abundantly in this deposit. H oel i n 1 909 gave this h orizon , which consists o f a red fine sandstone, the name " 300 m a bove sea-Ievel " .
The fl fth h orizon, the " Polaris h orizon " , n a med after the very com mon fossil - Poraspis polaris n . sp. , wh ich occurs i n thousands o f species in the grey-green fine sandstone (Pl. I ) was also discovered i n 1 909- 1 0 by H oel and called " 250 m above sea-Ievel " . It is situated i m mediately on top of the red " Prim aeva horizon " and can be fou n d somewhat l ower d own at t h e edge of Frænkelryggen .
The last h orizon, the sixth, known o n Frænkelryggen is the "Ang
Iaspis h orizon". T h e beauti ful small forms of A nglaspis are very com m on in this nearly grey sand stone. This h orium was also already known by H oel, who collected fossils from t h is locality a n d called i t
" 200 m above sea-level " . O n t h e expedition i n 1 928, h owever, especially rich portions o f this h orizon were discovered by H ei ntz l ower down o n the south side o f Frænkelryggen .
The next sectio n was explored on the expeditions i n 1 925 and 28.
It was deposited along the East shore of Red Bay, on both sides of a stream running from the south corner of the Andree Glacier. H ere, only th ree horizons containing fossils were found : The fi rst was placed on the N side of the strea m , where in grey, quite coarse sandstone, a large n u m ber of bad ly-preserved fossils was foun d , and am ong them a small A nglaspis species was com mon. I t is, therefore, quite probable that this horizon corresponds more o r less with the " Anglaspis horizon"
o n Frænkelryggen .
1 4 JO H A N K l Æ R AND A N ATOL H E I N TZ
The next i s named the "Red horizon " because o f the red colour o f the sandstone. It i s situated on the S side o f the stre a m , about 1 00 m away fro m it. It can be traced running parallei to the stream into the country, towards the foot of the northern part of Ben N evis.
H ere in 1 928, i n a very steep cliff, a red horizon containing a quantity of badly-preserved fossiIs was discovered. Probably this h o rizon corre
spon ds to the "Red h orizon " on the shore.
The third h orizon, Iying on the shore, is the so-called " Rotundata horizon " (after Pteraspis rotundata n. sp.). I n the green-grey fine sandstone a n u m ber of relatively wel l preserved black fossiI s was found already i n 1 925. This horizon was not re-found on the N cliff.
The great section th rough all t h e Ben N evis deposits, w h i c h w e shall now discuss, w a s chiefly explored by H oel i n 1 909- 1 0. The collections fro m d i ffe re n t localities gathered during the exped itions in 1 925 and 28, were of a m o re occasional cha racter, but i t is not parti
cula rl y difficult to find the correct place of the new localities a m ong the 20 horizons determined by H oel.
The fi rst part of H oel ' s section is placed a long a stre a m running fro m the " First glacier " on Ben Nevis. This stream does not reach the sea, but falls into a larger stream , running along the west side of the Grand glacier.
The fi rst horizon i n this section Iying about 57 m above sea-leve!
is called " H orizon A " . After this, follow with sh ort intervals 8 other h o rizons, term ed with the l etters fro m B to I .
" H orizon B " i s situated 65 m , C-75 m , D- 8 1 m , E - 8 8 m , F- 90 m , G -I lO m , H-1 35 m , and, finally, 1-1 67 m above sea
level. All these h o rizons are petrograph ically somewhat a l i ke and represent a very hard, grey, of ten m icaceous sandstone. The fossiIs a re neither especially wel l preserved , nor riehly represen ted . The h orizons A, B, F and I a re relatively rieher than the others. I n 1 925 and 28, some fossils were collected in these h orizon s , and also on the W side of the no rthern part of Ben N evis, which part corresponds to the d i fferent horizons in the above mentioned profile A- I .
The next h orizons determined b y H oel are placed o n a very steep cli ff on the south side of the above-mentioned stream fro m the First glacier. This cli ff forms the northern l i m it o f a relatively flat plateau on the W side of Ben N evis. O n the cli ff, fossiIs h ave been collected fro m two h o rizons - 260 and 290 m above sea-Ievel respectively.
In addition, both o n the expeditions in 1909- 1 0 and 1 925-28 a n u m ber of fossiIs was collected i n the boulders found beneath and on the cliff.
A horizon very probably corresponding with one or a nother o f t h e horizons on t h i s c1i ff is "Vogti horizon " . The horizon, consisting of a fine red and grey sandstone with very well preserved wh ite fossils,
e y A T H A SPIDA 1 5 i s named after a sh ort and broad Pteraspis - Pl. vogti n. sp. collected there. It is widely distri buted and was for the fi rst time foun d in 1 928 on the N ridge of Ben N evis, and it was pursued to the northern plateau of Ben N evis.
We find the continuation of the section made by H oel o n the SW side of Ben N evis, where he has determ ined 1 2 horizons, from j to U. H orizon j lies 490 m, K- 497 m , L- 532 m, M- 577 m , N--623 m , 0-627 m , P- 653 m , Q- 675 m , R- 690 m , S- 7 1 3 m , T - 840 m and U- 900 m above sea-leve! respectively. All these hori
zons, composed o f finer and coarser grey, and green-grey sandstones, partly contain a l a rge quantity of fossils, h orizons K, L , N , O and R being particularl y rich.
On the expedition i n 1 925 no fossils were collected in this section , but a relatively rich m ateria l was brought together o n the above-men
tioned W plateau, :about 300-400 m a bove sea-Ievel. This horizon, which had been m ore extensively ex plo red i n 1 928 , con ta in ed a n u m ber of d i fferent fossils, and as especially the Ctenaspis form s were very abundant, this h orizon has been called the " Ctenaspis horizon". I t probably correspond s t o the horizons j, K and L i n H oel's section.
H igher up, on the W side of Ben N evis, a num ber of fossils was collected i n 1 928 mostly from the horizon between 500 a n d 600 m a bove sea-level ( Ben neviaspis horizon). This comparatively rich h o rizon m ay correspond to the O, P, Q and R h orizons i n H oel's section.
Another locality discovered in 1 928 , was a n a rrow, long tongue, situated on the N W side of Ben N evis between the First and Second glaeiers ( " Tunge " ) ; also the horizons found here m a y correspon d to the O-R i n H oel's section.
Besides all these system atically undertaken coilections on Frænkel
ryggen and Ben N evis, a great n u m ber o f fossils was gathered in d i fferent m oraines and debris beneath d i fferent steep ciiffs and ridges.
An excursion along Wulffs R idge to Mt. Wulff u ndertaken i n 1 928 and , further, to the south ridge of Ben N evis, did not give any parti
cularly interesting palæontological results. The deposits o n Mt. Wulff m ay correspon d to those on Frænkelryggen.
On Mt. Pteraspis, fossils have only been gathered i n 1 906 and 1 9 1 2 from 4-5 d i fferent horizons, and i t seems not i mprobable, that the l owest h orizon h ere corresponds to Anglaspis horizon on Frænkel
ryggen, and the uppermost, rou n d the Vogti h orizon on Ben N evis.
A s we have seen , the section through the Red Bay Series is very complete. The lowest part is foun d on Frænkelryggen, the youngest deposit at the top o f Ben N evis. The following table (pag. 1 6) gives th e pro bable relationship between the d i fferent horizons of the Red Bay Series.
1 6
fræn k elryggen Group 1909-1910 1925-1 928
I
I
200 m Anglaspis
Hor.
250 " Polari s
Hor.
300 » Pri maeva Hor.
Plant Hor.
Corvaspis H or.
Psammosl.
H or.
JO H A N KlÆR A ND A N A TOL H E I N TZ
T a b l e I l.
�
oce�
Mt. Pt."", B e n Nevis Group1928 1912
I I
?760-825
?650
Rotunda Hor.
Red Hori- zon
Anglaspis ? 50 H o r,
? Lowest by
Eri k Glaeier
I
I
1909-191 0
Hor. U (900 m)
» T (8W » )
» S (713 " )
" R (690 » )
" Q (67 5 » )
» p (653 » )
» O (627 » )
» N (623 " )
" M (577 " )
» L (532 » )
" K ('197 " )
» J (490 " )
Clitf u n d e r W. Plateau:
(290 m ) (260 » )
Hor. l (167 m )
" H ( 1 3 5 »
» G (11 0 »
" F ( 90 »
» E ( 88 »
" D ( 8 1 " )
" C ( 7 5 » )
» B ( 65 ,. )
" A ( 57 " )
192 5 1928
B e n n e v i asp. Hor.
I (500--600 m)
f
Tunge.\ Cte n a 'p's f Horiz o n
I
l?
I'
V ogti Hor.I
Red Hor. on N. clitf.
I
CY ATH ASPID A 1 7
MATERIAL AND METHODS. (A. H.)
As is m e n tioned above, the rocks where the fossiIs a re fou n d i n the R e d B a y Series, consist of d i fferent kinds of sandstone. The m ost abundant is a somewhat h a rd, often m icaceous grey sandstone , where the fossiIs in freshly-broken stones are d ark, often alm ost black, in m o re weathered parts, of a l ighter colour, whi te-grey to nearly wh ite.
T h e preservati on varies : i n m icaceous san dstone i t i s as a rule bad, in finer sandstone, o n the other han d , it can be very good. These grey sandstones of greatly varying structure and outl i n e a re especially cha racteristic o f the h orizons on Ben N evis, but they a re also fou n d in the uppermost p a r t of F rænkelryggen (Anglaspis h orizon). Beyond that, o n Fræ n kelrygge n , is the shaly grey-green sandstone, a lmost without mica, m ore characteristic. Especially the darker, green-grey fine shaly sandstone fro m the Polaris, and partly fro m the Plant h orizon s contain excellently preserved fossils, which, as a rule, a re rath er dark, but never black, with a fine glossy surface, d isplaying the fi nest detaiIs i n the structure of the d e n tine ribs, a n d in the pores of the sensory canal system . The m icroscopical sections, h owever, show n o finer details.
The red sand ston e occurs com paratively seldom and only in the lower part of the Red Bay Series. On Fræ n kelryggen the Prim aeva h o rizon is red , the sandstone is very fine, com pact a n d rich in fossiIs, wh ich here are n early white, of ten with a fai n t rose or light-blue colour. T h e preservation i s very good , the surface is glossy, and i n some cases, nearly tran sparent, the i n n e r structure of the shieid s h owing i n d i stinctly through it. The Red h orizon in the " short section " and on the n orth c1i ff is m ore coarse. T h e fossils, wh ich i n some parts occur i n enormous num bers, a re badly preserved . They a re also h e re of a white colour, but the surface i s n o t glossy, and the macroscopical and m icroscopical structures a re d i fficult to see. Finally, on Ben N evis on the n o rth plateau and n o rth ridge occurs a red , a l m ost shaly, fine sandstone with a large num ber o f concretions. These concretions are m ostly blan k , and of m a n y h u nd reds which were crushed during t h e expeditions i n 1 925 -28 only very few contained fossil remains, while, o n t h e contrary , the red a n d grey-red sandstone found i n their i m mediate neighbourhood, contained a num ber of fine fossiIs. Apparently the fine slab with 6 com plete specimens of Pteraspis vogti Kiær, described by Kiær i n 1 927, is fro m t h i s horizo n . I t seems a l s o very pro babl e that t h e red concretion horizon found on Mt. Pteraspis, corresponds to that o n
Ben N evis.
A specifi c kind of rock represents the lowest h ori zon o n Fræn kel
ryggen (the Psa m m osteus horizon ) , whic h , at the same time, as m e n tioned
2
18 JOHA N KlÆR A N D ANATOL HEINTZ
above, is t h e oldest fossil-bearing horizon i n the Red Bay Series. The sandstone is h ere a rath e r c o arse, yellow-grey . The fossils are nearly black, except on the weathered surface w h ere the sandstone beco mes a l m ost yellow, t h e fossils are whitish , of ten with a tone of blue. They are badly p reserved and only sel d o m d isplay some finer details.
The preparation of the fossils was ca rried out by hand, with the help of chisels, and the fi n est detai l s were cleared out with the thinnest needIes. Often they could with advantage be prepared in alcohol. All prepa rations were done under binoculars m agnifying fro m 5 to 50 ti m es.
Besides t h e c h isels, a d e n tist's boring machine a n d gold h a m m e r were of ten used with very good results. The very fi n e , small grin d stones used by dentists i n th e boring machines, were especially favourable for the preparation of the sensory canals i n the shields of the Cyathaspida.
A num ber of fi n e preparates o f the sensory canals were carried out in this manner (Pl. V I I ; V I I I ) . The gold h amm er was more useful for the excavation of d i fferent tender pa rts o f the fossils. The corrosion with H C L was sometimes applied , for i n stance, to get a m ore d i stinet rel ief of the structure of the inner layers of the shields, when the outer layer had been ground o ff with the help of a boring m achine (Pl. V I I ; VI I I ) .
T h e serial sections were used on ly to a very l i m ited degree chiefly for the study of the front part of the head shield ; some sm all m odels were also prepare d .
All t h e preparations were made either by Professor K i æ r h i m self, or under his direction. A relatively large n u m ber of fossils have also been worked out by Dr. H eintz. All the p hotogra p h s i llustrating this paper were prepared in the Paleontological Museum in Oslo, and take n , under the d i recti on of Professor Kiær a n d Dr. H e i n tz, by Miss L . Monsen, Miss Torbjørnsen and Mrs. Zachariassen. The m icroph o tographs were partly done by Dr. H eintz and partly by Dr. Størmer, and t h e retouch of t h e ph otogra p h s c h i e fl y by M i s s Barsta d , Miss Torbjørn
sen and Mrs. Zachariassen . The d rawings were m ade fro m sketches of Professor Kiær by Miss Barstad and Mrs. Zachariassen, a few by Dr. H eintz. The serial sections a n d wax models were constructed by Cand. real Knaben .
All the n u m erous m icroscopical slides have been m a d e by the preparator of t h e Paleontological Museu m , Osl o , Mr. Sveen .
The authors will here express their best thanks to a ll who have helped with the p reparation of this pa per.
CY ATH ASPI D A 1 9
CLASSIFICATION
OF THE HETEROSTRACI.
(j.
K. &A.
H.)T h e first forms, belonging to the Heterostraci were described as early as i n 1 833 by Agassiz. He united them with the Cephalaspida and regarded them only as d i fferent speeies of this genus (C. rostratus, C. lewisii and C. lloydii) . Together with other " a rrnoured fish es " h e considered them as belonging t o the Ganoida.
In 1 847, Kner described a new form from Upper Silurian of Gallieia, whieh is strongly reminiscent of C. lewisii Ag. and C. lloydii Ag.
H e regarded them, h owever, not as belonging to fi shes at all, but as fragments of the i n ternal skeleton of a Cephalopod related to Sepia, and proposed for t h e m the generic name Pteraspis.
Some years later, Roemer ( 1 856) described remains fro m the Devonian of Eifel shale as Palæoteu this. This form was i n real it y closely related to C. lloydii Ag. , but Roe mer expressed the opinion , that h i s form, together with Kner's Pteraspida, was neither the re m ai n s of fi s h e s nor Cephalopoda, but represented t h e a r m o u r o f a Crustacea.
I n opposition to Kner and Roemer, H uxley ( 1 858, l) wrote that, in fact, there was no fou ndation for the supposed resemblance between Pteraspida on one hand and Sepia or Crustacea on the other. H e also proposed t o adopt the n a m e Gen. Pteraspis fo r t h e type o f fishes described by Agassiz as Cephalaspis lewisii, C. lloydii and C. rostrata.
H e regarded both the Gen. Cephalaspis Ag. and Gen. Pteraspis Kner as related to Chondrostei, but considered that they fo rmed a very distinet fa mily ( H uxley 1 858, 2) .
I t was, h owever, Lankester, who i n the fi rst part of h i s " Th e fishes o f the O l d Red Sandstone of Britain " ( 1 868) i ntroduced the n a m e Heterostraci. H e proposed t o divide t h e " Familia vel . Sub- O rder Cephalaspidae" H u xley, i n to two section s : A) Heterostraci - i n view
o f the special cha racteristic of their test, and B) Osteostraci - in reference to the occurrence of th e bony structure i n their cephalic s hields. The fi rst section, Heterostraci, was d ivided into three Genera : Scaphaspis, Cyathaspis and Pteraspis. Concerning the relationship o f the Fam . Cephalaspidae, Lankester agreed w i t h H u x l e y , t h a t it is nearest related to Chondrostei.
In the later parts of the s a m e " Monogra p h " Lankester, h owever, is m o re doubtful with rega rd to the near relations h i p between the Heterostraci and the Osteostraci. He also changed his opinion a bout the system atical position of the whole group a n d is very mueh i n doubt to whieh fo rms a m ong t h e fishes they a re related.
Sch mid t ( 1 873, 3) also expressed the opinion , that Heterostraci and Osteostraci cannot be united i n to one fa mily.
20 J O H A N K l Æ R A N D A N A TOL H EINTZ
Z ittel i n his well-known " Palæozoologie " , (Vo l . I I I , 1 887) also pointed out the great d i fference between Heterostraei and Osteostraei, givi n g them the range o f a n i n depen dent O rders. He did not, however, accept the a bove-mentioned n a m es proposed by Lan kester, but suggested to call the Heterostraei as O rder Pteraspida and Osteostraei as Order Cephalaspida. Both these O rders, together with a num ber o f oth ers (Plaeodermi, Chondrostei, A eanthodii) he reu n i ted as " U nterklasse Ganoidei'·. In the description of the Order Pteraspida (=Heterostraei) h e mentioned only fou r d i fferent Genera : Pteraspis, Cyathaspis, Lophostraeon? and Holaspis.
A w h olly n ew classiflcation principle of the oldest vertebrates was i ntroduced by Cope ( 1 889, 1 89 1 ) . He established a new class of Craniata Vertebrata, t h e Class Agnatha ( H eckel) characteristic of the a bsence o f the j aws, pectoral arches a n d ossified inner skeieton. T h e C 1 ass Agnatha constitutes two groups : The Cyclostomi, com p r i s i n g the living l a m preys and hag-fishes and the Ostraeodermi, which com bines the Pteraspida, Cephalaspida and Pteriehtyida (in 1 89 1 , Cope a l tered the n ame Ostraeodermi to Ostraeophori) .
The n ew n a m e Ostraeodermi was adopted by Woodward i n " Cata
l ogue " ( 1 89 1 ). H e regarded the Ostraeodermi as " a prim itive Piscin e sub-class o f uncertain affi nities " and divided it, correspond ing to Cope, i n to th ree Orders: Heterostraei, Osteostraei and Antiarehi, Order Heterostraei containing only o n e Family Pteraspidae with three Genera : Pteraspis, Palaeaspis (=Holaspis) and Cyathaspis.
The next year Rohon ( 1 893) in h i s paper " Di e O bersil urischen Fische von Oesel I I " , also d iscussed the relationship o f t h e oldest vertebrates. H e i s a l m ost of the same opinion as Woodward, but con
sid ers that " A ntiarchi" does not belong to the same group as Hetero
straci and Osteostraei. H e therefore proposed a new n a m e Sub-Class Protoeephali, which com bined the O rders Heterostraei and Osteostraei only. Some years later ( 1 896) Roh o n discussed m ore in deta i l the systematical division of the oldest vertebrates, and suggested two n ew n ames : Order A spidorhini i n stead o f Heterostraei and Order A spido
cephali for the Osteostraei. The fi rst O rder com prises only one Family Pteraspidae with thre e Genera: Pteraspis, Palaeaspis and Cyathaspis and one Sub-Genus Tolypaspis.
I n a text-book published in 1 895 Dean m entioned a division o f the pri m itive vertebrates, nearly corresponding to that given by Cope, only with the d i fference that, in stead o f the n a m e " Class Agnatha " , he proposed " C lass Marsipobranchii" which , h o wever, com prises the same forms as Cope's "Agnatha" : The Cyelostomi and Ostraeodermi.
In the fi rst edition o f the " G rund ziige der Palæozoologie " , Zittel ( 1 897) adopted the n a m e "H esterostraei" , i n stead o f Pteraspidae used
ey A T H ASPID A 2 1 i n 1 887, but instead o f Osteostraci he re-introduced the name A spido
cephali - a n ame for the fi rst time proposed by Brandt i n 1 866 in
cluding both Pteraspida a n d Cephalaspida, and, as men tioned above, later accepted by Rohon but on ly referring to Osteostraci ( = Cephala
spida) . Zittel conn ected the O rders Heterostraci, Aspidocephali, A n
tiarchi and A rthrodira i n a n indepen dent Sub-Class of fishes "Placo
derma", a Sub-Class co-ordinated with the "Ganoida" and "Teleostei".
H e remarked , h owever, that the systematical position of the " Placoderm a"
is u ncerta i n .
I n " O utl i n e o f Vertebrate Paleon tology " ( 1 898) , Woodward followed the d i vision of the primitive vertebrates, proposed by Cope, only with some small alterations. The Class Agnatha was d ivided i n to two Sub
CIasses Cyclostomi and Ostracodermi, the latter with three O rders : Heterostraci, Osteostraci and A ntiarchi.
On the contrary, Lan kester ( 1 897) pointed out that the Ostraco
dermi are not related to the Cyclostomi, and proba bly do not compose a n atural group, because the Heterostraci, Osteostraci and A ntiarchi can hardly be regarded as closely-related forms. In his opinion : " concerning the closer relationsh i p of these groups judgment must be suspended " . As we h ave seen, since Lankester i ntroduced the n a m e Hetero
straci ( 1 867), all later authors h ave i n general accepted h i s l imitation o f this group. The d i fferences lay fi rst in the names , which where p roposed by d i fferent i nvestigators, and, secondly, i n the various opinions concerning the relationship o f "Heterostraci" (= Pteraspidae � A spido
rhini) to other "Osfracodermi" and other fishes. The epochal papers by Traquair, have i n many respects changed and enlarged our knowledge o f these remarkable forms ( 1 899, l, 2 ; 1 900, I, 2 ; 1 902 ; 1 903) .
When studying the material of Coelolepid-like fo rms collected i n t h e upper Sil u rian rocks i n Scotlan d , Traquair came t o t h e result, that the microscopical structure o f the scales o f Coelolepis (known al ready from the investigations by Pander, Schmidt and Rohon), Thelodus and Lanarkia , i n man y respects are similar to those on the shield o f Hete
rostraci (Pteraspis). Moreover, he has shown , that Psammosteus a n d Drepanaspis also m u st be regarded as closely related to Pteraspis, as the general shape of t h e body a n d the single shields (in Drepanaspis) , a n d the m icroscopical structure o f t h e sh ield (in Psammosteus), are quite similar to those i n Pteraspis. Thus Traquair has greatly extended the l imits of the "Heterostraci". Besides the previously known Family Pteraspidae, he now added three new F a m ilies : Coelolepidae, Drepana
spidae and Psammosteidae. He remarks, however, that the last two Families are closely related and perhaps ca n be joined i n o n e.
Contrary to the opinion of Cope, Woodward and Dea n , Traquair did not regard th e Heterostraci as Agnatha forms, but e m phasized its
22 J O H A N K l Æ R A N D A N ATOL H E I N T Z
relati o n s h i p with the Elasmobranchii. According to h i m , the Coelole
pida , with its fi n e placoid sca les and fl at " pectoral " fi n s , a re m ost prim itive forms, wh ich in m a n y respects are closely related to the pri m i tive Elasmobranchii. Drepanaspis shows the next stage i n the devel opment. The single placo i d scales have h e re m e l ted togeth e r i n to s m aller and l arger scales and plates, covering the whole body, and the
" pectora l " fi n s (poste rior lateral corner) protected b y sol id plates ( = cor
nale) have beco m e u n m ovable. In Psammosteus the fusion is probably still stronger, and, fi nally, i n Pteraspis, the whole head and front part o f the body are covered with solid, th ick plates, and the " pectoral " fi n s have com pletely disappea red .
N everth eless, Traquair kept the n a m e S u b - Class Ostracodermi Cope, which h e divided into th ree O rders : Heterostraci, Osteostraci a n d , fi n ally, a new O rder A naspida, but excluded the Order A ntiarchi from the Ostracodermi.
Later authors generally akn owledged that the Coelolepidae, Drepa
naspidae and Psammosteidae, were com bined i nto the Order Hefero
straci. O n the contrary, Traquair's opinion about the Elasmobranch ii
nature i n the Heterostraci, provoked a great deal o f con trovers y . I n a review of Traquair's pa p e r , Woodward ( [ 900) strongly criti
cized his opinion, and considered that Cope's theory about the agn atha character o f the Hetetostraci " is for the present, the less beset with d i fficu lties " .
Also Dean, i n a pa per p u bIished i n 1 900, did not accept Traq uair's propositi o n , and i n troduced a new, quite d iverging classificatio n o f the Paleozoie vertebrates. He erected six i n dependent elasses for the fish
like forms. T h e fi rst, - C l a ss Ostracophori (a n a m e proposed by Cope in 1 89 1 i n stead o f Ostracoderm i) , contained th ree Su b-C[asses : Oste 0-
straci, Heterostraci and A ntiarchi. T h e seco n d , Class A rthrognathi is n ew, and contained two Sub-Classes A narthrodira a n d A rthrodira. The next, Class Cyclie i s erected fo r the Palaeospondylus only, t h e Class Protochordata for Tunicata and A mphioxus, Cl ass Marsipobranchia for Cyclostoma a n d , finally, the Class Pisces unites all other fishes.
In this pl ace may also be mentioned a series of papers, published by Patten ( 1 890, [ 90 [ , 1 903), also partly dealing with Heterosiraci. As i s well known, Patten regarded all Ostracodermi (Pteraspidae, Cephala
spidae and A sterolepidae) as representing d i ffere n t transitional fo r m s between A rachnoids and t h e vertebrates. T h i s opinion, wh ich Patten l a ter d iscussed more i n detail i n his paper : " Th e evol ution o f the Vertebrate " ( 1 9 1 2) , met with great scepticism fro m all other authors, and can h a rdly be accepted .
I n 1 902, J aekel pubIished a short paper " O ber Coccosteus und Beurteilung der Placodermen". H e reunited all t h e arm oured primitive vertebrates in one group "Placodermen" which , according to h i m , con-
e y A T H ASP I D A 23 stituted : Pteraspiden, Tremataspiden, Cephalaspiden, Coccosteiden, Ma
cropetalichthyiden und A sterolepiden, and " scheint die echte Fische zu sei n " . He pointed out, h owever, that " D ie ein zeln e n Typen der Placodermen befinden sich offenbar auf sehr verschiedener Ausbildungs
h o h e " . Thus Pteraspiden " h aben einen larvalen C h a rakter ziemlich rein beva h rt " , and Coccosteiden " ei n e ancestraie Stellung gegenliber den Ganoiden u n d n a m lich Chimeriden einnehmen " . He remarked , R n ally, i n con nection with t h e opin ion h e expressed as earl y as i n 1 896, that the Placodermi show some tetra pod c h a racteristics. As i s known , in a l l h i s papers, j aekel ad vocated the opinion that all Rshes are de rived from very pri m itive terrestrial anim als, wh ich have i n different periods passed into a n a quatie l i fe , where th ei r essential structures have been ch anged and adapted to their new li fe.
I n another short paper published the succeed i ng year ( 1 903) , j aekel proposed a new division of the a r m oured paleozoic Rshes. For the forms w here t h e head i s sharply divided fro m the body-armour (e. g. A rthro
dira and A ntiarchi), he i ntrod uced the n am e Temneuchenia. T h e Ptera
spida, Tremataspida and Cephalaspida, on the contrary , he p roposed to unite in another group Holauchenia; about the relationship of these two groups to each other and to other Rshes h e d i d not express a n y d istinet o p i n i o n , b u t o n l y remarked t h a t " Z u e i n e r Verteilung des Placo
dermata im weiteren Sinne in getre n n te Kl asse l i egt meiner Erachtens n och kein zwin gen der Grund vor " . O f greater interest are the general remarks about the development of th e skeleton in the vertebrates, which we R n d i n this paper. j aekel h ere for the R rst time expressed clearly that : I ) " sta m m esgeschichtlich eine Zerlegung oder Auflosung der an
fangs zusa m m e n hangenden Korperbedeckung eingetreten ist " , 2) " I n ner
halb der historischen Entwicklung . . . . zeigt sich eine schreitweise Re
d u ktion der Verknoch erung " . 80th these opinions were i n stri king con trast to the prevalent meaning o f that ti m e . Later investigation, h owever, has shown , that j aekel - i n general - h a s expressed a thoroughly correct view.
I n two s h ort papers Kemna ( 1 903, 1 904) gives a cri tical review of the pa pers published about the Ostracodermi, and d raws the conclusion that it i s m ost l i kely that the Ostracoderm i m ust be co m bi n e d with the Cyclostoma i n to t h e group Agnatha. He regards as u nacceptable Tra
q uair's theory thas the Heterostraci are rel ated to the Elasmobranchii.
Dollo on the con trary ( 1 903) , in a short paper about " Le Pteraspis dans I' Ardenn e " writes m o re reserved. H e considered the Heterostraci certainly as agnatha forms, but i s not quite sure th at they are related to the Cyclostoma, as it see m s not i m probable that the latter group s e c o n d a r i l y can change to beco m e agn ath a . Regarding their reia ti on with the Elasmobranch ii, Dollo also agrees with Traquair, maintaining that it i s n o t i m possible that " les Ostracodermes les pl us prim itive
