HARVARD UNIVERSITY.

LIBRARY

MUSEUM OF COMPARATIVE ZOOLOGY

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MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE.

VOL. XXXVI.

CAMBRIDGE, MASS., U. S. A.
1913.

1'ROPICAL PACIFIC.

Thr following Pithlications of the Museum contain Reports on the Dredging Operations in charge
of Alexander Agassiz, of the U. S. Fish Commission Steamer "Albatross," during 1S99
and 1900, Commander Jefferson F. Moser, U. S. N., Commanding.

I. A. Agassiz. Preliminary Report and List of Stations. With Remarks on the Deep-
Sea Deposits by Sir John Murray. Mem. M. C. Z., Vol. XXVI. No. 1. Janu-
ary, 1902. 114 pp. 21 Charts.

II. A. G. Mayer. Some Species of Partula from Tahiti. A Study in Variation. Mem.
M. €. Z., Vol. XXVI. No. 2. January, 1902. 22 pp. 1 Plate.

III. A. Agassiz and A. G. Mayer. Medusae. Mem. M. C. Z., Vol. XXVI. No. 3.

January, 1902. 40 pp. 13 Plates, 1 Chart.

IV. A. Agassiz. The Coral Reefs of the Tropical Pacific. Mem. M. C. Z., Vol. XXVIII.

February, 1903. 33, 410 pp. 238 Plates.

V. C. R. I5astm.\n. Shark's Teeth and Cetacean Bones from the Red Clay of the
Tropical Pacific. Mem. M. C. Z., Vol. XXVI. No. 4. June, 1903. 14 pp.
3 Plates.

VI. W. E. HoYLE. Cephalopoda. Bull. M. C: Z., Vol. XLIII. No. 1. March, 1904.
71 pp. 12 Plates.

VII. H. LuDwiG. Asteroidea. Mem. M. C. Z., Vol. XXXII. July, 1905. 12, 292 pp.
35 Plates, 1 Chart.

VIII. W. E. RiTTER and' Edith S. Byxbee. The Pelagic Tunicata. Mem. M. C. Z., Vol.
XXVI. No. 5. August, 1905. 22 pp. 2 Plates.

IX. Mary J. R.^thbun. The Brachyura. Mem. M. C. Z., Vol. XXXV. No. 2.
August, 1907. 54 pp. 9 Plates.

X. C. H. Gilbert. The Lantern Fishes. Mem. M. C. Z., Vol. XXVI. No. 6. July,
190S. 24 pp. 6 Plates.

XL A. Agassiz. Echini: The Genus Colobocentrotus. Mem. M. C. Z., Vol. XXXIX,
No. 1. November, 190S. S, 33 pp. 49 Plates.

XII. J. Murray and G. V. Lee. The Depth and Marine Deposits of the Pacific.
Meiri. M. C. Z., Vol. XXXVIII. No. 1. June, 1909. 170 pp. 5 Plates,
3 Maps.

XIII. W. C. Kendall and E. L. Goldsborough. The Shore Fishes. Mem. M. C. Z.,

X<,]. XXVI. No. 7. February, 1911. 10(1 pp. 7 Plates.

XIV. H. ilEVTii. The Solenogastrcs. Mem. M. C. Z., Vol. XLV. No. 1. June, 1911.

ISO pp. 40 Plates.

XV. A. M. Westergren. Echini: Echinoneus and Micropetalon. Mem. M. C. Z.,
Vol. XXXIX. No. 2. August, 1911'. 34 pp. 31 Plates.

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MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

AT

HARVARD COLLEGE.

VOL. XXXVI.

CAMBRIDGE, MASS., U. S. A.
1913.

/IDcmotvs of tbe Museum of Comparative Z00I005

AT HARVARD COLLEGE.
Vol. XXXVI.

THE PLAGIOSTOMIA.

(8HAEKS, SKATES, AND EAYS).

BY

SAMUEL GARMAN.

WITH SEVENTY - SEVEN PLATES.

PLATES.

CAMBRIDGE, U.S.A.:

printed for tbe /IMiseum.

September, 1913.

CONTENTS,

THE PLAGIOSTOMIA (SHARKS, SKATES, AND RAYS). By Samuel Garman.
528 pages. 77 plates. September, 1913.

List of Abbreviations.

ag-

angular.

1.

ao.

antorbital.

1'.

aqv.

aqueducts of the vestibule.

Is.

ar.

angular.

nik.

bhy.

basihyal.

msp.

bra.

outer branchial stay.

mtp.

bre.

inner branchial stay.

mx.

brr.

branchial rays.

na.

bstr.

basitrabeculae.

nv.

cbr.

ceratobr.anchials.

op.

chy.

ceratohyals.

pbr.

CO.

copula.

pbs.

cp.

partial copula.

pet.

e.

eye or orbit.

po.

ehy.

epihyal.

prp.

ebr.

epibranchial.

psp.

evs.

epitropeals, supra. & siibtropeals.

qpg-

exbr.

extrabranchials.

r. or rl

ebs.

ceratobranchials.

sbr.

fo.

foramen .

sc.

g-

gill lamellae.

so.

hbr.

hyobranehials.

sp.

hm.

hyomandibular.

X.

int.

intestine.

labials.

lateral expansion of rostral.

laterarstay.

lower jaws. Meckelian.

mesopterygium (nsp. pi. 67).

nietapterygiuni.

maxillaries, quadratopterygoids.

prenarial cartilages.

nasal valves.

opercular cartilages.

epibranchials.

posterior branchial support.

pectoral arch, shoulder girdle.

post orbital process.

projiterygium.

postspiracular cartilage.

quadratopterygoid.

ro.stral cartilage.

suprabranchial.s.

scapular.

supraorbital.

.spiracular.

basal element of eighth arch.

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PLATE 1.

PLATE 1.

CESTRACIONTIDAE.

Fig. 1-3. Cestracion zyoaena (Page 157). Fig. 4-6. Cestr.vjion tiburo (Page 160).

1. Lateral view of a .speeimen 27.f inches long.

2. Head from below.

3. Teeth from the side of the jaw.

4. Lateral view of a speeimen 21 J- inches lung.

5. Head from below.

6. Teeth from the side of the jaw.

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PLATE 2.

PLATE 2. .

CARCHARINIDAE. j

Fig. 1^. ScOLIODON TERRAE NOVAE (Page 115). Fig. 5-S. CaRCHARINUS LIMBATUS (Page 127). ■:

1. Lateral view of a specimen 215 inche.'; long. 1

2. Head from below. I

3. Teeth from the front and from the side of the jaw.

4. Scales from near the middle of the flank. ■

5. Lateral view of a specimen 34 inches long. . i

6. Head from below. j

7. Teeth from the front and from the side of the jaw. j
S. Scales from near the middle of the flank. i

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PLATE 3.

PLATE 3.

CARCHARINIDAE.

Fig. 1-3. Galeus glaucus (Page 145). Fig. -4-6. Carcuakinus PL.vryoDON (Page 126).

1. Lateral view.

2. Teeth from the forward end of tlie jaw.

3. Head from below.

4. Lateral view.

.5. Teeth from tlic forward end of the jaw.
6. Head from l^elow.

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PLATE 4.

PLATE 4.

CARCHARINIDAE and GALEORHINIDAE.

Fig. 1-5. Hemigaleus pectoralis (Page 150). Fig. 6-9. Galeohhinus l.^vis (Page 176).

1. Lateral view of a specimen 25i inches long.

2. Teeth from the inner side.

3. Forward teeth from the outer side.

4. Head from below.

5. Scales from the middle of the flank.

6. Lateral view of a specimen 27 inolies long.

7. Head from below.

8. Teeth from near tlie front end of the jaw.

9. Scales from near the middle of the fiank.

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PLATE 5.

PLATE 5.

GALEORHINIDAE and ISURIDAE.

Fig. 1-4. Tri.\ki.s HENLEi (Page 168). Fig. 5-9. Carciiahodon cabcharias (Page 32).

1. Lateral view of a specimen 25^ inches long.

2. Teeth from near the front end of the jaw.

3. Head from below.

4. Scales from near the middle of the flauk.

5. Lateral view.

6. Teeth from near the front end of the jaw.

7. Nostril.

8. Head from below.

9. Scales from near the middle of the flank.

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PLATE 6.

PLATE 6.

CARCHARIIDAE and ISURIDAE. i

Fig. 1-3. C.\KCHARi.\s T.\uRus (Page 25). Fig. 4-6. Isu'rus punct,\tu.s (Page 36).

1 . Lateral view of a specimen 42 inches long. ]

2. Teeth from the front end of the jaw. ]

3. Head from below. I

4. Lateral view.

5. Teeth from near the front end of the jaw.

0. Head from below. .

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PLATE 7.

PLATE 7.

VULPECULIDAE and ORECTOLOBIDAE.

Fig. 1-3 VuLPECULA MARINA (Page 30). Fig. 4-0. Gingltmostoma cirbatum (Page 54).

1. Lateral view of a specimen 53 inches long.

2. Teeth from near the front end of the jaw.

3. Head from below.

4. Lateral view of a specinien 14 j inches long.

5. Teeth from near the front end of the jaw.

6. Head from below.

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PLATE 8.

PLATE 8.

CATULIDAE and ORECTOLOBIDAE.

Fig. 1-6. Parmaturus pilosus (Pago 89). Fig. 7-10. Nebrodes macrurds (Page 58).

1. Lateral view of a specimen 17 inrhe.s long.

2. Head from below.

3. Teeth from near the front end of the jaw.

4. Scales from near the middle of the flank.

5. Lateral view of scales.

6. Ventral fins.

7. Lateral view of a specimen 31| inches long.

8. Teeth from near the front end of the jaw.

9. Scales from near the middle of the flank.
10. Lateral view of scales.

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PLATE 9.

CATULIDAE.

Fig. 1-5. Parm.\turusxanidr0s (PageOO). Fig. 0-9. Cephaloscyllium ventriosum (Page SO) .

1. Lateral view of a specimen 21 f inches long.

2. Head from below.

3. Teeth from near the front end of the jaw.

4. Scales from near the middle of the flank.

5. Egg-ca.se.

6. Lateral view.

7. Head from below.

8. Teeth from front and side of jaw.

9. Scales from tiifferent parts of the body.

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PLATE 10.

PLATE 10.

SQUALIDAE.

Fig. 1-4. Etmoptercs HiLLiANUS (Page 224). Fig. 5-8. Centroscyli.ium fabricii (Pago 2.31).

Lateral view of a specimen 9j inches long.

Teeth from the front end of the jaw.

Head from below.

Scales from near the middle of the flank.

Lateral view.

Teeth from near the front end of the jaw.

Head from below.

Scales from near the middle of the flank.

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PLATE 11.

220).

PLATE 11. I

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SQUALIDAE. |

Fig. 1-4. AcANTHiDiUM ROSTR.\T0M (Page 218). Fig. 5-8. Acanthidium hystricosdm (Page \

1

1. Lateral view of a specimen 31 inches long. j

2. Head from below. 1

3. Teeth from the front end of the jaw.

4. Scales from near the middle of the flank. ' !

5. Lateral view of a specimen 36j inches long.

6. Head from below.

7. Teeth from the front end of the jaw. ;

8. Scales from near the middle of the flank.

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PLATE 12.

PLATE 12.

SQUALIDAE.

Fig. 1-4. AcANTHiDiuM AcicuLATUM (Page 217). Fig. 5-8. Centrophorus acus (Page 199).

1. Lateral view of a specimen 'Ml inches long.

2. Teeth from the front end and from the side of the jaw.

3. Head from below.

4. Scales from the middle of the flank.

5. Lateral view of a specimen 32^ inches long.

6. Teeth from the front end of the jaw.

7. Head from below.

8. Scales from near the middle of the flank.

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PLATE 13

PLATE 13.

SQUALIDAE.

Fig. 1-4. Centrophorus .^tromargi.vatiis (Page 200). Fig. .5-8. Centroscymnos owstonii
(Page 205).

1. Lateral view of a specimen 34 inches long.

2. Teeth from the front end of the jaw.

3. Head from below.

4. Scales from near the middle of the flank.

5. Lateral view of a specimen 30f inches long.

6. Teeth from the front end of the jaw.

7. Head from below.

8. Scales from near the middle of the flank.

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SQUALIDAE. J

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Fig. 1-4. Squalds ACANTHiAS (Page 192). Fig. 5-8. CENTnoscYMNUs coelolbpis (Page 204).

1. Lateral view of a specimen 27 inches long.

2. Teeth from the front end of the jaw.

3. Head from below.

4. Scales from near the middle of the flank.

5. Lateral view of a specimen 44 inches long.

6. Teeth from near the front end of the jaw.

7. Head from below.

8. Scales from the middle of the flank.

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PLATE 15.

PLATE 15.

SCYMNORHINIDAE.

Fig. 1-3. SoMNiosus BREViPiNNA (Page 240). Fig. 4-C. Somniosus microcephalds (Page 241).

1. Lateral view of a specimen 75 inches long.

2. Teeth from side near the front end of the jaw.

3. Scales from the middle of the flank.

4. Lateral view of a specimen 106 inches long.

5. Teeth from near the front end of the jaw.

6. Scales from the middle of the flank.

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PLATE 16.

PLATE 16.

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RHINIDAE and PRISTIDAE.

Fig. 1-4. Rhina californica (Page 253). Fig. 5-7. Pristis clavata (Page 263).

1. Dorsal view of a .spccimpii 12j inches long.

2. Frontal view of the head.

3. Teeth.

4. Scales from the middle of the body.

5. Dorsal view of a specimen 24 1 inches long.

6. Forward teeth.

7. Scales from near the midtlle of the body.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 16.

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PLATE 17.

PLATE 17.

RHINOBATIDAE.

Fig. 1-2. Rhinobatus lentiginosus (Page 279).

1. Dor-sal view of a specimen 22j inches long.

2. Ventral view.

Mem. Mus. Comp, Zo'ol., Vol. 36.

Plagiostomes. Plate 17.

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PLATE 17».

PLATE 17a.

RHINOBATIDAE.

Fig. 1-2. RnmoBATDa rasus (Page 270). Fig. .3-4. Rhinobato.s planiceps (Page 2.S3).

1. Dorsal view of a specimen 14j inches long.

2. Head from below.

3. Dorsal view of a specimen 17| inches long.

4. Head from below.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes, Plate 17.'

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PLATE 17b.

PLATE 17".

RHINOBATIDAE and RAIIDAE.

Fig. 1-2. RniNOBATUS ACDTUs (Page 273). Fig. 3. R.u.\ kincaidii (Page 343).

1. Dorsal view of a specimen 13 y\ inches long.

2. Head from below.

3. Dorsal view of a specimen 12 inches long.

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PLATE 18.

PLATE 18.

RAIIDAE.

Fig. 1. Raia phitonia (Page 335). Fig. 2. R,\ia orn.ita (Page 336).

1. Dorsal view of a specimen 9-| inches long.

2. Dorsal view of a .specimen 65 inches long.

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Plagiostomes. Plate 18.

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PLATE 19.

PLATE 19.
RAIIDAE.

Fig. 1-2. Haia ackleyi (Page 336).

1. Dorsal view.

2. Head from below.

Mem. Mus. Comp. Zo'cjl., Vol. 36.

Plagiostomes. Plate 19.

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PLATE 20.

PLATE 20.

RAIIDAE.
Fig. 1-2. Raia eeinacea (Page 337).

1. Dorsal view of a specimen 19^ inches long.

2. Head from below.

Mem. Mus. Comp. Zool., Vol. 36,

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PLATE 21.

PLATE 21.
RAIIDAE.

Fig. 1-2. Raia scabbata (Page 340).

1. Dorsal view of a specimen 14J- inches long. M. C. Z. 30.5.

2. Dorsal view of a specimen 3U inches long. M. C. Z. 1139.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 21.

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PLATE 22.

PLATE 22.

RAIIDAE.

Fig. 1. R.'in DiAPHANES (Page 339). Fig. 2. Rata stabuliforis (Page 341)

1. Dorsal view of a specimen 36i inches long. M. C. Z. 1136.

2. Dorsal view of a specimen 47 J inclies long. M. C. Z. 1138.

Mem. Mus. Comp. Zool., Vol. 36.

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PLATE 23.

PLATE 23.

RAIIDAE.

Fig. 1-2. Raia eglanteria (Page 341).

1. Dorsal view of a specimen 21 inches long. M. C. Z. S7S.

2. Head from below.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 23.

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PLATE 24.

PLATE 24.

RAIIDAE and NARCACIONTIDAE.

Fig. 1-2. Raia kenojei (Page 351). Fig. 3. Narke japonica (Page 314). Fig 4-5. Raia
ptisCA (Page 349).

1. Dorsal view of a specimen 17 j inclies long. M. C. Z, 1125.

2. Mouth and nostrils.

3. Dorsal view of a specimen 10| inches long. M. C. Z. 1121.

4. Dorsal view of a specimen 4^ inches long. M. C. Z. 1240.

5. Ventral view.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 24.

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PLATE 25.

PLATE 25.

RAIIDAE and NARCACIONTIDAE.

Fig. 1. Raia SENTA (Page 338). Fig. 2. Nabcacion nobilianus (Page 310).

1. Dor-sal view of a specimen 225 inches long. M. C. Z. 250.

2. Dorsal view.

Mem. Mus. Comp. Zool., Vol. 36.

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PLATE 26.

PLATE 26.

XARCACIOXTID.^E.

Fig. 1. Narcixe brasiliensis (Page 297). Fig. 2. Xarcixe brasiliexsis baxcbofti (Page
298). Fig. 3. Xarcixe brasiuexsis coballixa (Page 298).

1. Dorsal view of a specimen 14| inches long. M. C. Z. 655.

2. Dorsal view of a specimen 9| inches long. M. C. Z. 752.

3. Dorsal view of a specimen 7j inches long. M. C. Z. 44.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 26.

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PLATE 27.

PLATE 27.

RAIIDAE.

Fig. 1-2. SvMPTEBYGiA .\cuT.\ (Page 370). Fig. 3-5. Mal-\corhin.\ MraA (Page 372).

1. Dorsal view of a specimen 13j inches long. M. C. Z. G32.

2. Ventral view of the anterior half of disk.

3. Dor.sal view of a specimen 14j inches long. M. C. Z. 226.

4. Ventral view of the anterior jjart of disk.

6. Dorsal and lateral views of the produced end of the snout.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 27.

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PLATE 28.

PLATE 28.

DASYBATIDAE.

Fig. 1-3. Urobatis sloani. (Page 402).

1. Dorsal view.

2. Lateral view of young from oviduct.

3. Ventral view of young from oviduct.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 28.

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PLATE 29.

PLATE 29.

DASYBATIDAE.

Fig. 1-2. Urobatis vermiculatus (Page 402).

1. Dorsal view. M. C. Z. 1055.

2. Ventral fins and tail from below.

Mem. Mus. Comp. Zool., Vol, 36.

Plagiostomes. Plate 29.

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PLATE 30.

PLATE 30.

DASYBATIDAE.

Fig. 1-2. Urotrygon mundus (Page 406).

1. Dorsal view of a specimen 8J- inches long. M. C. Z. 831.

2. Ventral view.

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Plagiostomes. Plate 30.

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PLATE 31.

417).

PLATE 31.
POTAMOTRYGONIDAE.

Fig. 1-2. POTAMOTRYGON CIRCDL-\RIS (P:lge 419). Fig. 3-4. POT.VMOTRYGON L.\TICEPS (Page

).

1. Dorsal view. Disk 1.5i inches long. M. C. Z. 291.

2. Mouth and nostrils.

3. Dorsal view. Disk 10 inches long. iM, C. Z. iiO'j.'oOr^

4. Mouth and nostrils.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 31.

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PLATE 32.

PLATE 32.

DASYBATIDAE.

Fig. 1-2. DASYB.4.TOS LATos (Page 383). Fig. 3-4. Dasybatus longtjs (Page 390). Fig. 5-6.
Dasybatus brevis (Page 396).

1. Dorsal view of a specimen 51 inches long. M. C. Z. 129.

2. Mouth and nostrils.

3. Dorsal view of a specimen 39j inches long. M. C. Z. 126.

4. Mouth and nostrils.

5. Dorsal view of a specimen 30-J inches long. M. C. Z. 371.

6. Mouth and nostrils.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 32.

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PLATE 33.

DASYBATIDAE.

Fig. 1-2. D.^STBATUS M.^RiNUS (Page 382). Fig. 3-1. Pteropl.^te.*. micrcra (Page 4U).

1. Dorsal view of a specimen 106 inches long. M. C. Z. 990.

2. Mouth and nostrils.

3. Dorsal view of a specimen 11 i inches long. M. C. Z. 95.

4. Head from below.

Mem. Mus. Comp. Zool., Vol. 36.

Flagiostomes. Plate 33.

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PLATE 34.

PLATE 34. I

POTAMOTRYGONIDAE. i

Fig. 1-3. DiscBus THAYERi (Page 426).

1. Dorsal view. Disk 12| inches long. M. C. Z. 563.

2. Mouth and nostrils.

3. Teeth from near the front end of the jaw.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 34.

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PLATE 35.

PLATE 36.

MYLIOBATIDAE.

Fig. 1-4. Myliobatis pnEMi.wiLLii (Page 432).

1. Dorsal view of a specimen 465 inches long. M. C. Z. 992.

2. Frontal view.

3. Ventral view.

4. Teeth from upper and lower jaw.s.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 35.

E. N. f iSCMER, DEL,

HELIOTVPE CO.

PLATE 36.

PLATE 36.

MYLIOBATIDAE.

Fig. 1-3. Aetomylaeus MACTJLATUS (Page 435). Fig. 4-6. Myliobatis pbrdvianus (Page 430).

1. Dorsal view of a specimen 28§ inches long. IVI. C. Z. 106.

2. Head from below.

3. Teeth from upper and lower jaws.

4. Dorsal view of a specimen 23 1 inches long. M. C. Z. (iSO.

5. Head from below.

6. Teeth from upper and lower jaws.

Mem. Mus. Comp. Zool., Vol. 36.

PUAGIOSTOMES. PLATE 36.

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PLATE 37.

PLATE 37.

RHINOPTERIDAE.

Fig. 1-3. Rhinoptera quadbiloba (Page 444).

1. Dor.sal view of a specimen 883 inches long. M. C. Z. 746.

2. Lateral view.

3. Frontal view.

Mem. Mus. Comp. Zool.. Vol. 36.

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PLATE 38.

PLATE 38.

MOBULIDAE.

Fig. 1-6. MoBDLA HYPOSTOMA (Page 453).

1. Dorsal view of a .specimen 39 inches long. M. C. Z. 083.

2. Frontal view.

3. Lateral view.

4. Head and gill openings from below.

5. Teeth from u])per jaw.

6. Teeth from lower jaw.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 38.

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PLATE 39.

PLATE 39.

CARCHARIDAE and MYLIOBATIDAE.

Fig. 1. Carchakias taorus (Page 25). Fig. 2. Myliobatis freminvillii (Page 432).

These longitudinal sections of the head and anterior part of the body contrast the conditions in one
of the lower of the Antacea with those in one of the most specialized of the Platosomia. The sections
show the cartilages of the skull, those of the forward portion of the vertebral column, and in part those
of the branchial apparatus; they show the brain, its chamber, the celular cavities of the head, tlie mouth
cavities from the lips to the stomach, the jaws, the teeth, tlie pads protecting the roof of the mouth, and
tlie arrangement of the muscles.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 39.

E. KONOPICKT, DEL,

PLATE 40.

PLATE 40.

CARCHARIDAE.

Fig. 1-3. ScAPANORHYNCHUs owsTONi. M. C. Z. 1048 (Page 28).

1. Brain from above.

2. Brain from the side.

3. Brain from below.

Comparison of tlie brain of thi.s spocie.s with that of Carcharias laurua, Plate 41, proves that Scapano-
rhynehus is the more ijrimitive of the two genera and conversely that Carcharias is nuioh the more ad-
vanced.

Mem. Mus. Comp. Zo'o'l., Vol. 36.

Plagiostomes. Plate 40.

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PLATE 41.

PLATE 41.

CARCHARIDAE.

Fig. 1-3. Carcharias tadhus (Page 25).

1. Upper surfaces of the brain.

2. Brain from the side.

3. Brain from below.

Though not of as high a type as that of Vulpeeula, Plate 42, and greatly outranked by the brains of
the Carcharinidae and Cestraciontidae, Plate 43, fig. 1-4, the brain of Carcharias taurus makes a con-
siderable advance from that of Scapanorhynchus, Plate 40.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 41.

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PLATE 42.

VULPECULIDAE.

Fig. 1-5. VULPECULA M.4RINA (Puge 30).

1. Brain after removal of the cartilage above it.

2. Brain after partial removal of the vessels and envelopes.

3. Lower surface of the brain removed from its chamber.

4. Brain from above.

5. Brain from the side.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 42.

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PLATE 43.

PLATE 43.

CESTRACIONTIDAE, CARCHARINIDAE, and SQUALIDAE.

Fig. 1. Cestbacion TiBDRO (Page 160). Fig. 2-3. Ce.stracion zygaena (Page 1.57). Fig. 4-5.
Carcharinus platyodon (Page 126). Fig. G-S. Galeocebdo arcticus (Page 148). Fig. 9-10.
Squalus acanthias (Page 192).

1. Dorsal view of brain. M. C. Z. 1292.

2. Dor.sal view of brain. M. C. Z. 1291.

3. Ventral view of brain.

4. Dorsal view of brain.

5. Nasal sac, bisected.

6. Dorsal view of brain. M. C. Z. 1288.

7. Ventral view of brain.

8. Lateral view of brain.

9. Dorsal view of brain. M. C. Z. 1298.
10. Ventral view of brain.

From tlie brain of tlie Carcliaridao, Plates 40 and 41, tliere was in the Vulpcculidae, Plate 42, a
marked increase in the plication of tlie hind brain with a less considerable one in the size of the fore brain.
In Plato 43, the much greater advance of the Cestraciontidae is seen both in the volume of the fore brain
and the complexity of the hind brain; these are more advanced in the Cestraciontidae than in the
Carcharinidae, the nearest alHes, for instances see fig. 4, Carcharinus platyodon, and figs. 6-8, Galcoccrdo
arclicus. Tliat the archaic family Squalidae is much lower in rank is indicated by the smooth hind
brain and the smaller amount of the fore brain.

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Mew Mus Comp, Zool .

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PLATE 44.

PLATE 44.

RAIIDAE and DASYBATIDAE.

Fig. 1-3. Raiascabrata (Page 340). Fig. 4-6. Raiastabuliforis (Page 341). Fig. 7. D.\.sy-
BATUS marinus (Page 382).

1. Brain from above. M. C. Z. 1289.

2. Brain from the side.

3. Brain from below.

4. Brain from above. M. C. Z. 1294.

5. Ear from the side.

6. Brain from below.

7. Brain from above. M. C. Z. 1287.

The comparative amount of the brain is mucli the same in these families but the higher rank of the
Dasybatidae is plainly indicated in the greater complexity of the hind lirain.

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PLATE 45.

PLATE 45.

CENTRACIONTIDAE .

Fig. 1-G. Centracion francisci (Page 180).

1. Teeth and jaws of a very young specimen.

2. Upper jaws and teeth of the same.

3. Lower jaws and teeth of the same.

4. Jaws and teeth of a larger specimen.

5. Upper jaws and teeth of the same.

6. Lower jaws and teeth of the same.

The teeth of the very young Centracion are all raptorial; they attest a soft-bodied food at this
stage, and a probable ancestry in forms with cuspidate teeth. The larger specimen shows the widening
of the hindmost teeth in preparation for the development of the grinders.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 45.

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PLATE 46.

PLATE 46.

CENTRACIONTIDAE.

Fig. 1-6. Centh.^cion francisci (Page 186).

1. Jaws of a specimen of medium size.

2. Upper jaws and teeth of the same.

3. Lower jaws and teeth of the same.

4. Jaws of an old individual.

5. Upper jaws and teeth of the same.

6. Lower jaws and teeth of the same.

These figures are from older specimens than those shown on Plate 45. Tliey indicate the decided
change that takes place in the feeding habits. The hinder teeth are all molars, with a low ridge instead
of cusps, and are much wider and more swollen than the front teeth, some of the hindmost of which
apparently have been succeeded, when renewed, by molars in their particular rows.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 46.

E, KONOP'CKV, DEL,

MELIOTTPE CO.

PLATE 47.

PLATE 47.

CENTRACIONTID AE .

Fig. 1-3. Centracion qdoyi (Page 187). Fig. 4-G. Centracion philippi (Page 182).

1. Lateral view of jaws and teeth.

2. Upper teeth and jaw.s from below.

3. Lower teeth and jaws from above.

4. Lateral view of jaws and teeth.

5. Upjier teeth and jaws from below.
G. Lower teeth and jaw.s from above.

Tlie ridges on the molars of younger .specimens become less prominent with age and use. The
harder the food in particular localities the more faint the ridges appear.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 47.

£. KONOPICKV, DEL.

PLATE 48.

PLATE 48.

RHINOPTERIDAE.

Fig. 1-3. Rhinoptera jussieui (Page 447). Fig. 4. Rhi.\opter.\ m.\rginata (Page 445).
Fig. 5-6. Rhinoptera lalandii (Page 445).

1. Teeth from a very young speeinien. M. C. Z. .311.

2. Teeth from a larger specimen. M. C. Z. 316. "^

3. Teeth from a large specimen. M. C. Z. 535.

4. Jaws and primary dentition. M. C. Z. 631.

5. Teeth from a medium sized specimen. M. C. Z. 534.

6. Teeth from a large .specimen. M. C. Z. 534.

Figures 1, 2, and 4 illustrate the changes in dentition during the period of rapid growth from very
young stages. The small round primary teeth in front of the pavements suggest derivation from an-
cestral forms with dentition resemhling that of some Dasybatidae. In fig. 3 and G are shown the teeth
of large specimens. Figures 3 and 5 show dentition that have been much affected by individual variation.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 48.

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PLATE 49.

PLATE 49.

MYLIOBATIDAE.

Fig. 1-3. Aetob.^tus N.\RiNARi (Page 441). Fig. 4-6. Myliob.^tis c.\lifornicus (Page 429).

1. Dentition of a very young .specimen. M. C. Z. 1079.

2. Dentition of a young specimen, larger than that shown in fig. 1. M. C. Z. 107(1.

3. Teeth of a large specimen. M. C. Z. 865.

4. Dentition of a very young specimen. M. C. Z. 348.

5. Dentition of a larger specimen. M. C. Z. 395.

6. Dentition of a specimen beyond the age of rapid growth. M. C. Z. 424.

In the youngest specimens of .\etobatus examined there are two rows of upjier and two rows of lower
teeth, fig. 1 and 2, each two quickly broadening and being succeeded by the broad teeth of the single
row retained through life. Possibly a still earlier stage may show a dentition more like that of Rhinop-
tera in its primary features. The earhest stage of Myliobatis figured has six rounded teeth in front of
the pavemeot, another has seven, thus accounting for all the rows of later stages, the median one only
becoming broad. It is to be expected that younger specimens wW show dentitions more in accord with
that of fig. 1, Plate 48, in Rhinoptera.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 49.

E. N. FISCHER, DEL,

HELlOTVPE CO.

PLATE 50.

PLATE 50.

ANTACEA.

Fig. 1, 6, 8. Galeorhinus LAEVis (Page 176). Fig. 2. Parmaturus pilosus (Page89). Fig. 3.
Triaenodon OBESus (Page 163). Fig. 4. Carcharinusmilbbrti (Page 133). Fig.5,11,12. Triakis
SEMiFA.sciATA (Page 165). Fig. 7. Triakis henlei (Page 16S). Fig. 9. Hemigaleus pectoralis
(Page 150). Fig. 10. Eugaleus galeus (Page 153). Fig. 13-16. Scoliodon longurio (Page 114).

The nictitating membrane in its early .stages is merely a longitudinal fold in the lower eyelid, not
reaching the edges of the lid, fig. 1 and 2. This is the case in the very young of Galeorhinus laeiris, fig. 1 ;
in older sijccimens of this species the fold reaches the edge of the lid at one end, as in fig. 6, but in large
ones the fold reaches the edge of the lid at both ends. fig. 8, and in tran.sverse section its outlines resemble
those of Triakis, fig. 12. The membrane attains its greatest perfection and more nearly covers the eye-
ball in the Cestraciontidae (Hammer Heads) and in the Carcharinidae, fig. 4, 13-16. In the Galeo-
rhinidae it is better described as a fold instead of as a membrane. In all cases it is likely that only
with some aid by muscular retraction of the ball can it be made to entirely cover the eye. Plate 50
indicates some of the variations in the pupil of the eye. The oblique pupil of the Centraciontidae
(Port Jackson Sharks) is shown on Plate 45, fig. 1.

Mem. Mus. Comp. Zoo'l., Vol. 36.

Plagiostomes. Plate 50.

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PLATE 51.

PLATE 61.

CARCHARIDAE.

Fig. 1-6. ScAPANOBHYNCHus owsTONi. M. C. Z. 104S (Page 28). Fig. 7. Carcharias tauru.s.
M. C. Z. 210 (Page 25).

1. Skull in longitudinal section.

2. Branchial skeleton from below.

3. Branchial skeleton from above.

4. Pelvis and radials.

5. Heart, conus, and arteries. ^

6. Intestine with spiral folds.

7. Intestine.

In most features the structure of Scapanorhynchu.s is closely allied to that of Carcharias. This is
very evident in the parts of the anatomy given on this plate but not previously figured. At first sight
the snout appears to present most divergence but nKjst of this di.sappears on closer comparison of the
long snout with the short one. The large cartilage in fig. 3 beliind the copula, glossohyal, Ijetwcen it and
the first ceratobranchial, is the first hypobranchial; it is present also in Carcharias, see Fiirbringer,
1903, Morph. jahrb., 31, pi. 17, f . 20 x. Three extrabranchials are shown in fig. 2 of Plate 51, a slender
rudiment of a fourth was present. As in most other items, the intestines of these genera, fig. 6, 7, have
much in common.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 51.

MtLlOTVPE CO.

PLATE 62.

PLATE 52.

Pelvis of ANTACEA and DIPNOI.

Fig. 1. ScoLioDON LONGURio. M. C. Z. <594 (Page 114). Fig. 2. Hemig.^leus pector.\lis.
M. C. Z. 847 (Page 150). Fig. 3. Prlstiophorus j.^ponicuis. M. C. Z. 104.5 (Page 246). Fig. 4.
Protopterus ANNECTEN.S. M. C. Z. 8964. Fig. 5-7. Cer.\todus for.steri. M. C. Z. 9827.

1-5. Lower view.

6. Upper view.

7. Lateral view.

The pelvis of the Antacea, fig. 1-3, is radically different from that of the Dipnoi, fig. 4-7. The
differences are of such characters that no evidences of close relationships are evident. Tiie structure
in the sharks, the Antacea, is farther than that in certain of the more specialized of the Platosomia, the
Potamotrygons, for instance, Plate 64, fig. 1-2, from that in these Dipnoi; yet undoubtedly such re-
semblances as exist between the pelvis of the Lung Fishes and that of the River Trygons, in the median
propclvic cartilage, is due to similarity of conditions and habits and not to inheritance from common
ancestors. The pelvis of Polypterus is still more remote, nearer to that of bony fishes.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 52.

E. N. FISCHEH, DEL.

MELIOTYPE CO.

PLATE 63.

PLATE 63.

Pelvis of PLATOSOMIA.

Fig
Fig
Fig
Fig
Fig
Fig

Upper and lower surface.

Uraptera agassizii. M. C. Z. 549 (Page 367).
Narc^-Cion californicus. M. C. Z. 43 (Page 311).
Urobatis .sloani. M. C. Z. 3.5 (Page 402).
Taenidra lymma. M. C. Z. 23 (Page 399).
Da.sybatus marinds. M. C. Z. 641 (Page 382).
Pteroplatea altavela. M. C. Z. 386 (Page 415).

The pelvis of the Raiidae, fig. 1, with tlie lateral prepelvic processes, recalls that of Cyclobatis,
a fossil genus. The pelvis of Narcacion, fig. 2, is raioid, but is more arched backward in the middle.
Figures 3-6 represent the Dasybatidae, in which family the organ is more like that of the Antacea, which
have neither lateral nor median processes in front of the pelvis.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 53.

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E. N. FISCHER, DEL.

HELIOTVPE CO.

PLATE 54.

PLATE 54.

Pelvis of PLATOSOMIA.

POTAMOTRTGON CIRCULARIS. M. C. Z. 296 (Page 419).
DiscEus THAYERi. M. C. Z. 006 (Page 426).
Myliobatis freminvillii. M. C. Z. 1160 (Page 432).
Aetobatus narinari. M. C. Z. 389 (Page 441).
Rhinoptera jussiedi. M. C. Z. 863 (Page 447).
Fig. 6. Mobula hypostoma. M. C. Z. 683 (Page 453).

Fig.

1.

Fig.

2.

Fig.

3.

Fig.

4.

Fig.

.5.

The figures on this plate are from a group of the Platosoinia characterized by a median process in
front of the pelvis, among other features. The process is shortest in the Myhobatidae, fig. 3^, longer in
the Mohuhdae, fig. 6 and longest in the Potamotrygonidae. Its presence has no bearing on a question
of affinity with Dipnoi, Plate 52, fig. 4-7.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 54.

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PLATE 55.

PLATE 56.

ANTERIOR VERTEBRAE.

Fig. 1. Callorhynchus TRiTORis. M.C. Z. 173. Fig. 2. Chimaera monstro.sa. M.C. Z. 326.
Fig. 3. Pristis microdon. M. C. Z. 302 (Page 26.5). Fig, 4. Rhinobatus percellens. M. C. Z.
430 (P.ago 278). Fig. 5. R.\ia erinacea. M. C. Z. 358 (Page 337). Fig. 6. Pot.\motrygon lati-
CEPS. M. C. Z. 290 (Page 417). Fig. 7. Taeniura ly.mma. M. C. Z. 620 (Page 399). Fig. 8.
Myliobatis californicos. M. C. Z. 636 (Page 429). Fig. 9. Aetobatus n.'Uiinari. M. C. Z. 677
(Page 441). Fig. 10. Rhinoptera jussiedi. M. C. Z. 863 (Page 447).

Figure.s 1 and 2 show the condition of the vertebrae in the Chi.smopnea, how few of them are in-
cluded in the consoHdation, the articulation of the erectile spine, and the condition of the notochord,
without rings in Callorhynchus, fig. 1, with rings in Chimaera, fig. 2. Figures 3-10 are from among the
lowest to the highest of the Platosomia. They indicate the gradually increasing number of the vertebrae
taking part in the anchylosis, with the decrease in size and withdrawal backward of tlie lateral wings or
stays so prominent in the Pristidae, fig. 3, the scapulary attachment of the shoulder girdle superior in
Pristidae and Rhinobatidae, fig. 3-4, inferior in the Raiae, fig. 5, and a lateral articulation in Dasybatidae,
fig. 7, Potamotrygonidae, fig. 6, Myliob.atidae, fig. 8, Rhinopteridae, fig. 10 and the Mobulidae. The
different styles of attachment of the .shoulder girdle apparently divide the Platosomia into groups. A
considerable increase in irregularity of vertebrae and processes obtains as the most specialized
genera are approached.

Mem. Mus. Comf 7oot. Vol, 36.

PLAGtOSTOMES. PLATE 55

E. N. FISCHER, DEL

COCKAVNE. BOSTON

PLATE 56.

PLATE 5e.

HEART.

Fig. 1. HEPTR.\NCHiAa PERLO. M. C. Z. 945 (Page 21). Fig. 2. Scaph.^norhynchus owstoni.
M. C. Z. 1048 (Page 28). Fig. 3. Orbctolobds j.\ponicu.s. M. C. Z. 1038 (Page 50). Fig. 4.
Cephai-o.scyllidm nMBRATiLE. M. C. Z. 1044 (Page 80). Fig. 5. Lsoru.s pdnctatd.s. M. C. Z.
1249 (Page 36). Fig. 6. Prwtiophorus japonicu.s. M. C. Z. 1045 (Page 246). Fig. 7. Rhinoba-
Tus PERCELLEN.S. M. C. Z. 430 (Page 278). Fig. 8. Di.scobatos sine.nsis. M. C. Z. 1120 (Page
289). Fig. 9. Narcacion marmoratus. M. C. Z. 42 (Page 305). Fig. 10. Nakke japonica.
M. C. Z. 1114 (Page 314).

Rather generally the number of rows of valves in the conus of the Antacea decrea.ses with advance in
rank, with increase in specialization. For proof of this compare Heptranchias, fig. 1, Scapluuiorhynchus,
fig. 2, Isurus, fig. 5, and Pristiophorus, fig. 6, with Orectolobus, fig. 3, and Cephaloscyllium, fig. 4. In the
Platosomia the rule does not hold so well, as is shown by comparing Rhinobatus, fig. 7, of this Plate with
greatly specialized types, Plate 67, fig. 1-6.

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PLATE 57.

PLATE 67.

HEART.

Fig. 1. Sympterygia acdt.\. M. C. Z. 632 (Page 370). Fig. 2. Dlsceus th.^yeri. M. C. Z.
297 (Page 426). Fig. 3. Pteroplatea altavbla. M. C. Z. 336 (Page 415). P'ig. 4. .\etobatus
NARiNAEi. M.CZ. 677 (Page 441). Fig. 5. RHiNOPTERAjos.siEni. M.C.Z. 863 (Page 447). Fig. 6.
MoBDLA HYPOSTOMA. M. C. Z. 683 (Page 453). Fig. 7-10. Ceratodus forsteri. M.C.Z. 9827.

The majority of tlie more differentiated of the famihes of the Platosomia have a larger number of
rows of valves in the conus than others commonly accepted as much lower in rank ; that is, with increase
in specialization decrease in the number of valves does not obtain as regularly as in the Antacea. This
is substantiated by contrast of Rhinobatus, Plate 56, fig. 6, with .^etobatus, fig. 4, Rhinoptera, fig. 5,
and Mobula, fig. 6, of Plate 57.

Figures 7-10 represent the heart of Ceratodus.

For fig. 7 the jiericardium was slit longituilinally and turned to the sides; for fig. 8 both conus and
ventricle were opened, showing the upper end of the so-called spiral valve in the passage from the ventri-
cle into the conus, the lower end of the passage with the end of the hinder one of a series of large thick-
walled valves of the aditus, and the chamber of the ventricle with the basal, posterior, fibrous pad.
The conus is thrown open in fig. 9 disclosing the transverse series of large valves immediately behind the
arteries, and behind that series another transverse series of smaller valves; this figure also shows the
somewhat spiral course of the opening from the ventricle, in dotted lines, with the end of a large valve at
its origin, and the fibrous pad at the side of which is a large opening controlled by muscles into the ventri-
cle. The inner two of the dotted lines rougldy indicate the position of a longitudinal series of large
valves laid bare in fig. 10 which shows one of the transverse series of large valves in front cut open to
prove that this .series originated from one of the hinder of several transverse series, the smaller valves q^
the anterior series being included by the larger valves; this figure also shows a longitudinal scries in the
aditus of large valves one of which was formed from each of the transverse series of small valves, at its
left in the figure.

Mem. Mus. Comp. Zool., Vol, 36.

,;vits. Plate 57.

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PLATE 68.

PLATE 58.

Intestines of ANTACEA and CERATODUS.

Fig. 1. Heptranchias PERLO. M. C. Z. 945 (Piige 21). Fig. 2. Cephaloscyllium umbratile.
M.C.Z. 1044(PagcSO). Fig. 3. Lsurus punctatus. M. C. Z. 1249 (Page 36). Fig. 4. Hemigaleus
pECTORALis. M. C. Z. 847 (Page 150). Fig. 5. Pristiopuorus japonicus. M. C. Z. 1045 (Page
246). Fig. 6. Ceratodu-s fosteri. M. C. Z. 9827.

There are marked differences between the intestine of the Plagiostomia and that of Ceratodus.
Tlie stomach of tlie former is distinctly separated fi-om the spiral intestine, while that of the latter is a
continuation forward of the spiral itself. The stomach and intestine of Ceratodus, fig. 6, form a con-
tinuous spiral the characters of the inner surfaces of which change from the villous of the stomach proper
to the absobent of the intestine in a single turn of the winding course. The number of turns in Ceratodus
is nine or ten; the axis of the spiral is firm and muscular. The number of turns in the intestinal spiral of
the Plagiostomia varies in those dissected here from four in Hemigaleus, fig. 4, to thirty-nine in Isurus,
fig. 3.

i

Mem Mus. Comp Zool.. Vol. 56.

-n.ATF 58.

e. N rise H EP, cei.

eeCMArrxK aO!tTor<

PLATE 69.

PLATE 69.

Fig. 1-2. Sqdalus acanthias. M. C. Z. 35 (Page 192). Fig. 3. Ginglymostoma cirratum.
M. C. Z. 819 (Page 54). Fig. 4-6. Chlamydo.selachus anguineto. M. C. Z. 1247, 1285 (Page 14).
Fig. 7-8. MoBULA HYPosTOMA. M. C. Z. 683 (Page 453). Fig. 9-10. Rhinoptera jussibdi.
M. C. Z. 863 (Page 447).

Figure 1, | natural .size, and fig. 2, natural .size, exliibit the outer and the internal yolk-sac, the
heart with arteries, the liver, the stomach, and the intestine. Figure 3, /j natural length, is the egg of
Ginglymostoma, the embryo showing through the shell. Figure 4-5, f nat., show the egg with the
embryo of Chlamydoselachus. Fig. 7-8 show the ajjpearance of the gill plates of Mobuhi, and fig.
9-10 those of Rhinoptera. There is in the latter a longitudinal division of the plates into upper and
lower parts, in fig. 9 there are also seen modifications to some e.xtent intermediate in character between
the plates in fig. 10 and those of Mobula.

Figure 6, of Chlamydoselachus, was made for comparison with the type and with figures in more
recent articles by Furbringer and Goodey. In a number of points it is at variance with the figures men-
tioned and agrees more nearly with the type. There is no point behind the middle of the first basihyal,
as in Fiirbringer, 1903, Morph. jahrb. 31, pi. 27, f. 18 or in Goodey, 1910, Proc. Zool. .soc. Lond., pi. 43,
f. 6 "bbr. 1 (?)." The basibranchials are more numerous and regular than in either of the mentioned
figures. The hypobranchials are present in five pairs, the hindmost pair being displaced and resting
below the junction of the sixth ceratobranchial and the basibranchial; these cartilages are those figured
as the vestigial seventh arch, Goodey, loc. cU., pi. 43, fig. 6, "b a 7 (?)." The seventh arch was dis-
covered and figured by Furbringer, 1903, as an "eventuel Rudiment einer siebenten Kiemenbogens";
it is of much greater development in this Plate than in either of the other figures.

Mef.- M-rs, COMP, ZOOL.. Vol. 36.

EiCMCR Jk ROeTTER. O C I-

PLATE 60.

PLATE 60.

ANTACEA.

Fig. 1-4. G.tLEORHiNus L.^EVis (Page 17G). Fig. 5-9. Sqd.^lus ac.\nthi.\s (Page 192).

1. Nearly natural length. M. C. Z. 1301.
2-3. Nearly natin-al length. M. C. Z. 1304.
4. Nearly natural length. M. C. Z. 1303.
.5. Two thirds natural length.
6. Twice natural length.
7-9. Natural size.
5-9. M. C. Z. 1305.

Figure 1 represents the egg in its membranous envelope before the appearance of the embryo.
Figures 2-4 show the embryo with the egg near the time the latter attaches it.self to the wall of the
oviduct, the attachment being a consequence of active development of the blood vessels and rapid
depletion of the nutriment of the egg. Partially attached eggs, before entire disappearance, are con-
siderably modified on the side in contact with the wall to which after the egg is absorbed the embryo
remain.s attached by the cord. The egg of Squalus, fig. 5 and 7, is one that carries a sufficient amount
of nutriment for the development and growth of the embryo without attachment to the surrounding
walls. The distribution of the blood vessels over the yolk differs much from that in fig. 2-4.

Mfm. Mus. Comp Zool.. Vol. 36

PLAGiosTOMts. Plate 60.

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PLATE 61.

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PLATE 61.

PLATOSOMIA and ANTACEA.

Fig. 1-3. Nabcacion MARMORATUS (Page 305). Fig. 4-5. Naecacion nobilianus (Page 310).
Fig. 6. Narcine timlei (Page 300). Fig. 7-8. Chlamydoselachus anquineds (Page 14). Fig.
9-11. Rhina caufornica (Page 253).

1-3. Various stages from De Sanctis, 1872.

4-5. Four fifths and natural length. M. C. Z. 1016.

6. One and two thirds natural length.

7-8. One and three fourths natural length. M. C. Z. 1285.

9-10. Five sixths natural length. M. C. Z. 916.

11. Two and two thirds natural length. M. C. Z. 916.

The first three figures illustrate the squaliforra raiiform and torpetliform stages socalled by De
Sanctis (1872, AUi Reale accad., 5, pi. 1, fig. 3, G, 9.) In fig. 3 the forward extension of the pectorals, at
the sides of the batteries, is strongly marked while the lateral growth of the antorbital process ultimately
forming the front of the disk has hardly begun; at this stage the latter merely forms a pad in front of the
head. Figures 4 and 5 from a specimen off the coast of New England illustrate the lateral growth of the
antorbital portions of the disk to meet the forward extensions of the pectorals and, with the obliteration
of the notch opposite each eye, complete the disk. See the .skeleton of N. marmoralus on Plate 67,
ao. The batteries are well developed and the disk completely outlined at a very small stage of Narcine
timlei, fig. 6. In connection with fig. 7-8, showing the young Chlamydoselachus with well differentiated
fins and extern.al gills, see also fig. 4-5, Plate 59. The embryo of Rhina mliforiiica, fig. 9, was attached
to an enormous mass of yolk, longer and many times the weight of the little shark. Figures 10 and 11
show the intestines and their connection with this yolk, the dotted lines indicating the entrance in front
of the spiral folds.

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Mem. M'us. Comp. loo..

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^I.ATE 62.

PLATE 62.

ISURIDAE.

Fig. 1-3. IsuRus PUNCTATTTS (Page 36).

1. Dorsal view of the skull, vertebrae, branchial cartilages, and shoulder girdle.

2. Lateral view of the skull, jaws, teeth, branchial cartilages, and shoulder girdle.

3. Ventral view of the skull, jaws, teeth, branchial cartilages, vertebrae, and shoulder girdle.

J

Mem. Mus. Comp. Zool., Vol. 36.

PLAGtOSTOMES. PLATE 62.

-EL'OTVPE CO,

E. Ft. FiSCwEft. DEL

PLATE 63.

PLATE 63.

ISURIDAE.

Fig. 1-6. IsuRUS PUNCTATTJS (Page 36).

1. Pectoral fin.

2. Pelvis and ventral or pelvic fins.

3. Vertebral column, second dor.sal fin, and the anal fin.

4. First dorsal fin.

5. Caudal fina and vertebrae.

6. Scales from near the middle of the Hank.

iViEM. Mus. COMP. 2o6'l., Vol. 36-

Plagiostomes. Plate 63.

E. H. Fischer, del.

mELIOTVPE CO.

i

PLATE 64.

PLATE 64.

PRISTIOPHORIDAE and PRISTIDAE.

Fig. 1. Pristiophorus japonicus (Page 246). Fig. 2-3. Pristis microdon (Page 265).

1. Dorsal view. M. C. Z. 1045.

2. Dorsal view. M. C. Z. 302.

3. Ventral view. M. C. Z. 302.

A species of the Antaeea is placed by the side of one of the Platosomia to give prominence to differ-
ences between the two groups, which aiipear especially, among others, in tiie jaws, the branchial skeleton,
the .shoulder girdle and the pectoral fins. Tlie girdle of tlic shark, fig. 1, is remotely attached to the
vertebrae in its scapulary extensions; it is considerably arclied and the fins are placed rather behind its
transverse axis. In the ray, fig. 2, the girdle is firmly and superiorly attached to the vertebrae by means
of a scapular element and the fins are lateral and forward of the articulations as well as behind them.
The copula, hhij, is divided into sections, segmentetl, and dist inct from the cartilages behind it ; in the ray
it is unsegmented and is attached to the ceratohyals, chij {ehy in Plate). Strong cartilages appear in the
gill covers of the ray, sp. The postbranchial stay, jd&.s, has its greatest development in Pristis and, as
shown in the following plates, dwindles in approaching the rays of highest rank.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 64.

E. N. FISCHER, DEL

HELIOTVPE CO

PLATE 66.

PLATE 65.

RHINOBATIDAE.

Fig. 1. RHYNCHOBATU.S DjiDDENSis. M. C. Z. .806 (Page 268). Fig. 2. Rhinobatus pehcel-
LENS. M. C. Z. 435 (Page 278). Fig. 3. Syrrhina breviro.stris (Page 285).

The skeleton of the Rhinobatidae is closely allied to that of the Pristidae. The copula, hbr 1, is
unsegmeiited, the other basibranchials are broadened fused and contorted, the antorbital, ao, is extended
farther outward from the skull and the shoulder girdle is much widened. The basibranchials arc sketched
from young individuals and must of course differ considerably from those of larger or adult sijecimens.

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PLATE 66.

PLATE 66.

DISCOBATIDAE.

Fig. 1-3. DiscoBATUS SINENSIS (Page 289).

The figures are taken from a female twenty-five and one fourth inches in lengtli. Tlie lower surface,
fig. 2, has been dissected out so as to show the skeleton and the viscera. The mouth, fig. 3, was drawn as
it appeared before di.ssection. Attention is directed to several features in which Discobatus to some
extent approaches the Narcaciontidac. The rostral cartilage, r, ends abruptly a short distance in front
of the skull and is supjilemented by soft flexible branched extensions somewhat like those of Narciue.
The antorbital, ao, has greatly extended forward and outward. The branchial rays are expanded at
their outer extremities. There is a triangular group of ampullae, an incipient battery, opposite tlie end
of each lower jaw. The copula, h br', is unscgmented. The pelvis is very wide; it is provided with
a slight anterior process at each end. The proiJterygiuni of the ventrals is considerably branched at
its distal end. With the exception of the liver, which is indicated by dotted lines, the viscera are
shown in position.

Mem. Mus. Comp. ZobX., Vol. 36.

Plagiostomes. Plate 66.

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PLATE 67.

PLATE 67.

NARCACIONTIDAE.

Shoulder girdle to snout.

Fig. 1-2. Narcacion marmohatds. M. C. Z. 42 (Page 305). Fig. 3-4. Nakke japonica.
M. C. Z. 1114 (Page 314).

1, 3. Ventral view.

2, 4. Dorsal view.

The Torpedoes form the most distinct group of the Platosomia. Aside from the electric apparatus
their skeletons would serve to place the family at a distance from the other families. The shoulder
girdle, the antorbital and its function in the forward part of the disk, the peculiar rostral cartilages, the
spiracular cartilages and their supplementals, and the slender branchial rays with their rounded plate-
like extremities are very different from the same parts in the framework of the nearest allies. The in-
complete copula, CO, cp, and the arrangement of the joints of the projiterygial basalia of the pectoral fins
also illustrate this; and at the same time the genera of the Narcaciontidae differ widely from one another:
— compare the elongate skull, long rostral cartilages, the anteriorly much dissected antorbitals, the wide
postbranchial stays, phs, the arrangement of the propterygial joints of the pectoral basalia, and the
regularly articulated branchihyals of Narcacion marmoratus with the short skull, short rostral cartilage,
the slightly dis.sected antorbitals, the narrow extent of the postbranchial stays, the labial cartilages, and
the consolidated branchihyals of Narke japonica.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 67.

E. N. FISCHER, OEL.

MELIOTVPC 00.

PLATE 68.

PLATE 68.

RAIIDAE.

Fig. 1. Raia erinacea. M. C. Z. 358 (Page 337). Fig. 2. Uraptera agassizii. M. C. Z.
549, (Page 367). Fig. 3-4. Sympterygia acuta. M. C. Z. (332 (Pago 370).

Tlio iiroterygial ba.salia of tlic pectoral fins of the Narcaciontidae have numerous joints between the
antorbital, ao, and the pectoral arch, /ic/; the Raiidae have comparatively few, most often but a single
one, that is two segments in the pectoral ba.sc oppcsite the gills, an arrangement gaining in firnniess of
the disk along the sides of the branchial chamber. Marked variations occur among the genera of Raiidae.
In Sympterygia, fig. 3 a semicartilaginous mass in front of the skull displaces the rostral cartilage; in
Malacorhina the rostral cartilage is lacking and the forward part of the skull is much like that of the
Dasybatiflac. In general the hyobranchials are reduced, but the copula, hbr', is complete and not
segmentetl as in Dasybatidae nor divided as in Narcaciontidae. The scapular, sc, overlaps the girdle.
The prominent lateral prepelvic processes recall similar ones on the fossil genus Cyclobatis.

Mem. Mus. Comp. 2o6l., Vol. 36.

Plagiostomes. Plate 68.

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MELIOTYPE CO.

E. N. FlSC^'ER, OEL.

PLATE 69.

PLATE 69.

RAIIDAE and DASYBATIDAE.

Fig. 1-2. Malacorhina mira. M. C. Z. 226 (Page 372). Fig. 3. Urotrygon aspidurus.
M. C. Z. 555 (Page 405). Fig. 4-5. Urobatis sloani (Page 402).

A peculiarity of Malacorhina is the absence of a rostral cartilage, the front of the skull in consequence
resembling that of Dasybatus. The scapular attachment overlaps the girdle as in the other Raiidae.
A feature not noticed in the others is a small movable cartilage, x, resting above the base of the sus-
pen.sorium, a rudiment perhaps of a sometime complete arch which included the spiracular cartilages and
the pterygoquadrates, the upper jaws. The copula is unsegmented and the joints in tlie bases of the
pectorals oppo.iite the gills are like those of the family in general.

Urotrygon, fig. 3, and Urobatis, fig. 4-5, agree in most respects with other Dasybatidae; they have
no rostral cartilage, there is no joint in the pectoral base opposite the gills anfl the scapular articulations
are against the ends of the scapula, .sc. not above the girdle as in the Raiidae. Urotrygon, fig. 3, appar-
ently lacks the median segment of the copula, as in the Torpedoes. In Urobatis there is a slender
elongate supraspiracular cartilage.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 69.

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PLATE 70.

PLATE 70.

POTAMOTRYGONIDAE.

Fig. 1-2. PoT.iMOTRYGON ciRcuLARis. M. C. Z. 295 (Page 419). Fig. 3—1. Disceus thaykki.
M.C. Z. 606 (Page 426).

1, 3. Dorsal view.

2, 4. Ventral view.

The River Trygons are olose allies of the Dasybatidae. They have no rostral cartilage from the
skull forward, the copula, hbr', is sogmented, the jjropterygial basalia of the jjeetoral fins, pap, are .strong
and in a single piece between the antorbital and the shoulder girdles, and the postliranchial sta.y, pbs,
is reduced. Disceus, fig. 3, has a small hardly distinct antorbital cartilage, ro, a broad postspiracular
psp, a wide bar in the shoulder girdle and short orbital proce.s.ses; Potamotrygon, fig. 1, has a larger
antorbital, a narrow and elongate postspiracular, a narrower bar in the girdle and longer orbital processes.
In both genera the ceratobranchi.als are more or less solidly anchylcsed. Disceus has elongate narrow
o])ercular cartilages, op 1-5.

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Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 70.

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HCLiOTVfE CO.

PLATE 71.

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PLATE 71. I

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DASYBATIDAE.

Fig. 1-2. Dasybatus guttatus. M. C. Z. 639 (Page 391). Fig. 3. Dasybatus zugei.
M. C. Z. 23 (Page 398). Fig. 4-5. Taenidra lymma. M. C. Z. 620 (Page 399). i

1, 3, 4. Dorsal view. ^

2, 5. Ventral view. j

Rigidity of the disk around tlie head and tlie branchial chamber is secured by the elongation and '

firmness of the propterygial segment of the pectoral ba,se. The copula, hbr', unlike that of the Raiidae,
is segmented; anteriorly, in the ba.sibranchial portion, it broadens toward the suspensorium, hyomandi-
bular, hin. The ceratobranchials are more or less consolidatefl and enlarged, as also the basihyals. The
branchial ray, or rays, at the outer ends of the ceratohyals and ceratobranchials are attached to the bases
of the pectoral at their outer ends but are not modified.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 71.

E. n flSCMER, DEL

MELIOTVPt CO.

PLATE 72.

PLATE 72.

Fig. 1-2. Ptehoplatea altavela. (Page 415).

Except in what is more directly affected by the broadening of the body and the pectorals this genus
exhibits no great departure from the other Dasybatidae. The copula is segmented, the propterygial
segment of the pectoral base is strong and elongate and reaches slightly beyond the antorbital, the
ceratobrancliials, cbr, are fused at their inward ends, and the basihyals form a large broad shield-like
plate. The shoulder girdle has been mollified in several particulars; the pectoral bar, /ict, has widened
and the scapular bracts to the pro- nie-so- and metapterygia have elongated, though the .scapula, sc, from
which they extend outward, is comparatively little changed.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes. Plate 72.

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PLATE 73.

PLATE 73.

MYLIOBATIDAE.

Fig. 1. Myliobatis aquila. M. C. Z. 623 (Page 431). Fig. 2. Myliobatis perdvianus.
M. C. Z. 636 (Page 430). Fig. 3. Aetomylaeu.s maculatus. M. C. Z. 106 (Page 435). Fig. 4.
Aetobatus n.\rinari. M. C. Z. 677 (Page 441).

Three of the genera of the Myliobatidae are figured here. The fourth, Pteromylaeus, stands be-
tween Aetomylaeus and Aetobatus; it has the narrowed head and the separation of the pectorals as in
the latter, but has a different dentition. Myliobatis, fig. 1, differs from the rest of the family in pos-
sessing a continuous pectoral along the side of the head, and in absence of the modification of the pectoral
rays opposite the lower jaw. In all the genera the propterygial segment of the base of the pectoral
extends beyond the antorbital, that is beyond the head. In the very young this .section of the base
appears to be somewhat irregularly segmented, but these indications are transitory, probably ancestral
tokens. The branchial ray at the outer end of the ceratobranchial is slightly modified at its point of
attachment to the pectoral base. The extra series of cartilages, ei<s, in front of the branchial rays along
the ceratobranchials and epibranchials are more developed than in preceding families. The extrabran-
chials, sbr, above and below, are well developed; they are modified branchial rays. The opercular
cartilages, op 1-5, are fringed. Extra cartilages, eus, appear upon or along the band.s of the gill lamellae;
these may be called epitropeal , the upper ones being supratropeals, the lower subtropeals.

Mem. Mus. Comp. Zool., Vol. 36.

Plagiostomes, Plate 73.

E. H. FISCHER, DEL.

"EllOTYPE CO.

J

PLATE 74.

PLATE 74.

RHINOPTERIDAE.

Fig. 1-2. Rhinopteea jussiedi. M. C. Z. 863 (Page 447).

The skull of the Rhinopteridae i.s short, broad, and somewliat indented in front. The cephalic fin.s
are quite distinct from the pectorals, are situated at a lower level, and are not widely separated from one
another in front of the mouth. The mouth is widened and the jaws arc broadened, the narial cartilages
are long and broad. The propterygial bases of the pectorals are imsegmented at the sides of the gill
chambers, imless it be in very young stages, they are enlarged and strengthened, and to further conduce
to stability and finnness the lateral stays. Is, hra, bre, are so greatly modified as to be hardly recognizable
as gill rays; the anterior. Is, is directed forward over the antorbital, ao, as a single elongate cartilage;
the second, brr, fig. 1, is directed outward, segmented and turned back in its outer segment; the third,
bra, and the following show the outer segment firmly attached to the base of the pectoral while the inner
segment of the ray, bre, is broadened and enlarged into a sort of hammer-shape, solidly attached to the
ceratobranchial and the epibranchial at their junction, and al.so to the outer stay or segment, bra. The
epitropeal cartilages, supratropeal and subtrojieal, ens, form regular series above the arches, and irregular
ones below them. The extrabranchials, sbr, supra and sub are large. The mesopterygia are much
reduced or fused with the girdle, pet. The anterior km, in fig. 1, shoidd be sp. Changes in the
structure of the gills leading towards Mobula are seen in the Rhino])teridae; the inward section of each
lamina takes on more of the functions of protection and of pro]5elling the food toward the stomach while
the outer section is more concerned in purifying the blood, see Plate 59, fig. 9-10.

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PLATE 75.

PLATE 75.

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MOBULIDAE. j

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Fig. 1-2. MoBUL.^. HYPOSTOMA (Page 453). '

A course of evolution resembling the actual course traversed by Mobula from an ancestral form like
the Dasybati may be traced through Myliobatis, Aetomylaeus, and Rhinoptera by means of the pectoral

and the cephalic fin.s — connected and meeting in front of the head and lacking the modified radials |

opposite the gills in Myliobatis, disconnected at the sides but still meeting in front and possessed of the I

modified radials in Aetomylaeus and Rhinoptera — or by means of the projjterygial bases of the pectorals, j

or even by means of the outer branchial rays their attachments and their transformations quite as readily j

as by means of the dentition, the narial cartilages, or the skull itself. The cranium of Mobula is broader |

and more indented in the forehead than that of Rhinoptera. The cephalic fins are distant from one
another in front of the head ; they are radically separated from the pectorals, the anterior rays of which 1

latter have undergone considerable changes of form. The mouth is widened; the jaws are elongate. ,

The outer brancliial rays are transformed into braces or stays. Is, bra, bre, in a more firm attachment of

the gill arches. The extrabranchials, sbr, are highly developed; originally they were branchial rays, I

and they do not closely correspond with the extrabranchials seen, on Plate 51, fig. 2, or on Plate 62, j

exbr and sbr, in the shark. The stays Is, bra, bre originated as noted under Plate 74 for those in Rhinop-
tera. The second ray from the outer stay is lengthened, wider outward, and has a slender curved
extremity; it also serves as a brace. Nearly all of the rays on the ceratohyals, chi/, are segmented and
more or less changed in form. The long strips of cartilage, ews, first appearing as small lumps and later I

fusing, upon the bends in the gill lamellae, parallel with the gill arches, are adventitious and are first
noted in Myliobatidae, Plate 73; they are named epiiropeal cartilages, the upper supratropeal, the
lower sublropeal. The opercular cartilages, op 1-.5 attain their maximum development in this family.

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PUBLICATIONS

OF THE

MUSEUM 0¥ COMPARATIVE ZOOLOGY

AT' HARVA^RD COLLEGE.

There have been published of the Bulletin Vols. I. to LIL;
of the Memoirs, Vols. I. to XXIV., and also Vols. XXVI. to XXIX.,
XXXI. to XXXIV., XXXVI., XXXVII., XXXVIII., and XLI.

Vols. LIII. to LVII. of the Bulletin, and Vols. XXV., XXX.,
XXXV., XXXIX., XL., XLII. to XLVIII., of the Memoirs, are
now in course of publication.

A price list of the publications of the Museum mil be sent on appli-
cation to the Director of the Museum of Comparative Zoology, Cambridge,
Mass.

Date Due

A

JUN 3 0 1988

Harvard MCZ Library

3 2044 066 301