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THE 






FOSSIL TURTLES 



OF 



NORTH AMERICA 



BY 



OLIVER PERRY HAY 




WASHINGTON, D. C. 
Published by the Carnegie Institution of Washington 

1908 



Carnegie Institution of Washington, Publication No. 75 



ISAAC H. BLANCHARD COMPANY 
NEW YORK 



QE 

g(oZ 

H3 



PREFACE. 



In this treatise on the Fossil Turtles of North America there are described 
266 species, of which 76 are regarded as hitherto unknown to science. In the 
preparation of this work the writer has had access to most of the collections which 
contain remains of North American fossil turtles. The most important of these 
collections is that of the American Museum of Natural History, in New York. 
In this are found many of the specimens described by Professor E. D. Cope, 
including many of his types. In addition to these, large numbers of turtles have 
been brought together by the expeditions sent out by this museum during the past 
fifteen years. Free access has been given the writer to the materials in the United 
States National Museum, where there are many of the specimens described by 
Dr. Joseph Leidy and Professor Cope; to those of the Academy of Natural Science 
of Philadelphia, where are found other materials rendered precious by the labors 
of the authors just mentioned; to those of the Carnegie Museum, Pittsburgh; 
the Field Natural History Museum, Chicago; the University of Kansas, Lawrence; 
the University of Texas, and the University of Nebraska. At Yale University 
the writer has been permitted to study and describe valuable materials brought 
together by Professor O. C. Marsh, besides other specimens which form the 
types of species described more recently by Dr. George R. Wieland. Thru the 
courtesy of Professor W. S. Valiant some of Dr. Leidy 's types preserved at Rutgers 
College were made accessible. Specimens for study have been sent to the writer 
from most of the museums mentioned; also from the University of Chicago, by 
Mr. S. W. Williston; from the University of California, by Dr. J. C. Merriam; 
from the Geological Survey of Canada, by Mr. L. M. Lambe; and from the 
Vanderbilt University, Nashville, by Professor L. C. Glenn. 

It has been the author's earnest wish to see all the types of the hitherto described 
species; and most of these have come under his notice. Unfortunately some are 
without doubt utterly lost; others have, for the time, disappeared from view. 

The author has endeavored to illustrate as fully as possible the species described. 
Whatever mayprove to be the little or greatvalue of the text, the writer can commend 
the illustrations. By far the greater number of the figures of the plates are from 
photographs which were taken at the American Museum of Natural History by 
Mr. A. E. Anderson. Other photographs and drawings have been furnished by 
the Geological Survey of Canada thru Mr. L. M. Lambe; others by Dr. George R. 
Wieland, of the Yale University Museum; others by Dr. W. J. Holland, director 
of the Carnegie Museum, Pittsburgh. The photographs of Basilemys sinuosa 
came from the Field Natural History Museum, thru Dr. E. R. Riggs. A consider- 
able number of the drawings found in the plates were prepared many years ago, 
for the late Dr. George Baur, by the United States Geological Survey; thru the 
courtesy of the Survey these were placed in the hands of the writer. The major- 
ity of the drawings that appear in the text were executed by Mrs. Lindsay Mor- 
ris Sterling, artist in the department of vertebrate paleontology in the American 
Museum of Natural History. A number of these text-figures are the work of Mr. 



Ill 



IV PREFACE. 

R. Weber, of the same museum. Most of the wash-drawings that appear in the 
plates were produced by Mr. Erwin C. Christman of the American Museum of 
Natural History. 

The thanks of the author are due, first of all, to the Carnegie Institution of 
Washington for the support it has given him in the preparation of this monograph; 
in the next place, to Professor H. F. Osborn, of the American Museum of Natural 
History, New York, for the opportunity to use the materials in that museum; 
finally, to all the persons and institutions above mentioned and others who have 
contributed in any way to whatever there may be of value in this work. 

It is not believed to be necessary to append a list of the papers and memoirs 
consulted in the preparation of this monograph; inasmuch as the writer's Bibliog- 
raphy and Catalogue of the Fossil Vertebrata of North America, Bulletin 179 of 
the United States Geological Survey, records the literature of the subject up to the 
year 1901 and the important writings since published are cited in the text of this 
monograph. 

Washington, November 20, 1907. 



THE FOSSIL TURTLES OF NORTH AMERICA. 



ON THE SOURCES OF OUR KNOWLEDGE OF THE FOSSIL TURTLES OF 

NORTH AMERICA. 

The study of the fossil turtles of North America began in 1851, when Dr. 
Joseph Leidy described, under the names Stylemys nebrascensis, Testudo lata, 
Emys hemispherica, and Emys oweni, the extremely common fossil turtle of the 
Oligocene Badlands of the present state of South Dakota, then a part of the Terri- 
tory of Nebraska. It is true that in 1842 Dr. Richard Harlan had described and 
figured (Amer. Jour. Sci., xliii, p. 144, pi. iii, figs. 2,3) as Chelonia coiiperi a bone 
which he believed to be the femur of a large sea-turtle; but it is quite certain that 
the bone was no part of any turtle. Dr. Leidy continued at intervals up to 1889 to 
describe new species of fossil turtles. Most of Dr. Leidy's shorter papers appeared 
in the Proceedings of the Philadelphia Academy, but his most important illustrated 
works on the subject are found in D. D. Owen's Geological Survey of Wisconsin, 
etc., 1852; in the sixth volume of the Smithsonian Contributions to Knowledge, 
1854; and in the first volume of the monographs of Hayden's Geological Survey 
of the Territories, 1872. Professor E. D. Cope began his publications of species 
of fossil turtles in 1867; his last paper containing matter on the subject was pub- 
lisht in 1899, after his death. His papers on the subject are numerous and will 
be found cited in the writer's Bibliography and Catalogue of the Fossil Vertebrata 
of North America, 1902. Cope's most important expositions of the turtles are to 
be found in the fourteenth volume of the Transactions of the American Philosophical 
Society, 1869 and 1870; in the second volume of the Hayden Survey monographs, 
1875; in volume four of Wheeler's Survey West of the looth Meridian, 1877; and 
in the third volume of the monographs of the Hayden Survey, 1884. 

Professor O. C. Marsh described only three species of fossil turtles. No new 
fossil species are to be credited to Dr. George Baur, but he was the author of a 
number of papers which made important additions to our knowledge of their 
structure and relationships. Dr. S. W. Williston and Dr. E. C. Case have con- 
tributed a number of valuable papers on the subject, especially on the turtles 
derived from the Niobrara beds of Kansas. Dr. George R. Wieland has given 
especial attention to the marine turtles of the Upper Cretaceous; and, especially, 
he has described that remarkable chelonian monster Archelon ischyros. 

Other authors who have busied themselves more or less with the North American 
chelonian population of past times are J. Z. Gilbert, L. M. Lambe of the 
Canadian Geological Survey, Dr. F. B. Loomis, W. J. Sinclair, E. S. Riggs, and 
O. P. Hay. The results of the studies of the authors mentioned are that more than 
260 species of fossil turtles are now known from the geological deposits of North 
America; the nearly complete structure of a considerable number of these has 
been determined and much of that of others; and much light has been gained 
regarding the history and relationships of the members of the order. Undoubtedly 
many additional species will be discovered as the years pass away and species now 
known only from a few bones will become far better known. 

I 



4 FOSSIL TURTLES OF NORTH AMERICA. 

costals as rib-heads, which articulate with the vertebral centra. At the front of the 
shell each rib-head articulates with two centra, at their junction with each other; 
more posteriorly, the rib-head falls farther and farther behind the intervertebral 
articulation. There is no movement of the rib-heads on the centra, nor of these on 
one another. 

The first dorsal vertebra articulates with the last cervical, permitting a very 
free motion. Its ribs are short, have no costal plate, and lie closely joined to the 
front of the rib of the first costal plate. From this it will be seen that the second 
rib has coalesct with the first costal plate, the third rib with the second costal, and 
so on. The tenth dorsal rib is short and slender; its distal end is consolidated with 
the eighth costal plate, and has the upper end of the ilium abutting against it. 

In life the bones of the carapace and the plastron are covered by a number of 
horny plates, the scutes. Where the edges of any two of these meet they impress a 
furrow in the bone, forming a sulcus. When the skeleton is prepared the scutes 
fall off, but the sulci remain to betray the number and form of the scutes. In the 
figures here shown (figs. I, 2), as in nearly all the figures of this work, the sulci are 
represented by stippled bands; the sutures between the bones, by zigzag Hnes. 
In fig. I the scutes are represented on both sides of the shell, but the symbols of 
the names are placed only on the right side. Immediately in front, at the midHne, 
there is a small scute, the nuchal {nu. s). Then comes a row of five large scutes, 
the vertebrals {y. i,v. 2, etc.), each extending out beyond the neural bones. The 
sulci separating these scutes cross respectively the first, third, fifth, and eighth neu- 
rals. On each side of these vertebrals is a row of four large scutes, the costals (c. s, 
i; c. s, 2; etc.). The sulci between these descend respectively on the second, 
fourth, sixth, and eighth costal bones. 

The borders of the carapace are invested by a series of marginal scutes, twelve 
on each side (i, 2, 3, etc., on right side). The sulci dividing these from the costal 
scutes run along near the upper border of the peripheral bones. At the free borders 
of these peripherals the scutes turn down and appear on the under sides of the 
bones. 

It will be observed that the scutes coincide neither in number nor position with 
the underlying bones. It is seldom that the sulci follow the sutures. This matter 
will be discust hereafter. 

In fig. 2 are represented the plastral scutes, the characters indicating the names 
appearing in the right side of the drawing. A median longitudinal sulcus runs 
from the front to the rear of the plastron, separating the scutes of each pair. In 
front is a pair of gular scutes (g); then a pair of humerals {hum); followed by the 
pectorals {pec), the abdominals {ab), the femorals {fern), and finally, by the anals 
{an). Just behind each axillary notch is an axillary scute; while just in front of 
each inguinal notch is found an inguinal scute. The marginal scutes seen in this 
figure are the same that appear in fig. i. 

We may now examine the vertebrae in front of and behind the dorsals. In all 
of the turtles there are normally 18 presacral vertebrae, of which 8 belong to the 
neck. The more anterior and the more posterior cervicals are the shorter. The 
neck as a whole is about as long as the dorsal series of vertebrae. The first is com- 
posite, consisting of four distinct pieces. On each side is a neural arch, aiding in 
forming the neural canal. Below, these abut on a median piece, the hypocentrum. 
These three bones unite in forming a concavity, into which fits the ball-like occipital 
condyle. Behind the arches and the hypocentrum is the odontoid process, the proper 
centrum of the first cervical. Behind, this articulates with the centrum of the 
second cervical but does not become anchylosed with it. 



OSTEOLOGY. 5 

Of the other cervicals the arches are separable from the centra along a line of 
cartilage. The neural arches are all low and devoid of spines. There are no 
lateral processes. As regards the articular ends of the centra, there is great diversity. 
In Trachemys scripta, the second and third are convexo-concave; the fourth and 
the eighth are convexo-convex; the fifth is concavo-convex; and the seventh, concavo- 
concave. The articulations between the fifth and sixth, the sixth and the seventh, 
and the seventh and the eighth are extended from side to side and divided medially, 
forming a true hinge joint, which permits very free motion up and down, but 
restricts it from side to side. The anterior and the posterior zygapophyses are 
little elevated above the centra and are placed far apart. These arrangements 
contribute to free motion in a perpendicular plane, but limit it in a horizontal. 

Behind the last dorsal vertebra come two sacrals. Their ribs expand distally 
and articulate with the upper ends of the iha. The sacrals are followed by a number 
of caudals, about 15, but varying with the species, or even in individuals. Most 
of these have transverse processes. 

The skull of Trachemys scripta seen from above (fig. 3) presents three pairs of 
bones which join at the median line. In front are the prefrontals, extending back- 
ward to the middle of the orbits. The anterior ends roof over the nasal cavity. 
A strong process descends from each to join the vomer and the palatine, and to 
form the front wall of the orbit. Behind the prefrontals are placed the larger 
jrontals. They aid in forming the rim of the orbits. The parietals are important 
bones, inasmuch as they form the roof and much of the lateral walls of the brain- 
case. The anterior end of each sends downward a strong process which joins the 
pterygoid. Besides the pterygoid, the lower border of the parietal articulates with 
the prootic and the supraoccipital. The latter bone is greatly prolonged backward, 
as it is in almost all turtles. It forms a small part of the boundary of the foramen 
magnum. 

The maxilla bounds the nasal cavity on the side, the orbit below, and its lower 
border forms an acute cutting-edge. In life this edge is covered with a horny 
sheath. Posteriorly the maxilla articulates with the jugal. The hinder part of the 
rim of the orbit is formed of the jugal below and of the postfrontal above. These 
two bones form a postorbital bar of moderate width. 

A large tympanic cavity is excavated in the quadrate, an extremely important 
bone among the reptiles. Below the cavity mentioned, the quadrate descends to 
form a movable articulation with the lower jaw. In the hinder border of the quad- 
rate is a small, but deep notch for the passage of a long, rod-like bone, the columella. 
Interposed between the anterior border of the quadrate and the jugal bone is the 
quadrato jugal. The jugal and quadratojugal form the zygomatic arch. Above 
and behind the quadrate is the squamosal. 

The sides of the hinder part of the skull are occupied each by a long excavation, 
the temporal fossa. The floor of this is formed of the parietal on the inside, of the 
prootic and paroccipital in the middle, and of the quadrate and squamosal on the 
outside. 

Fig. 4 represents the skull of the same species as seen from below. In front are 
the premaxillce, bounding the nasal cavity below and entering into the roof of the 
mouth. On each side and behind the premaxilla is the maxilla. It presents out- 
wardly the cutting-edge already mentioned. Its inner border joins, in front, the 
vomer, posteriorly the palatine; the middle portion is mostly a free edge, forming 
the lateral boundary of the choana. Between the two borders is a broad triturating, 
or alveolar, surface, which in life is covered with a horny sheath. Along the middle 
of this, parallel with the cutting-edge, is a sharp ridge, slightly tootht. 



FOSSIL TURTLES OF NORTH AMERICA. 



The midline behind the premaxillje is occupied by the single vomer. Anteriorly 
it divides the nasal passages from each other; laterally it articulates with the 
palatines; posteriorly, with the pterygoids. The palatines assist in roofing the 
nasal passages and in forming the triturating surface mentioned. Between each 
and the maxilla of its side is seen an opening, the posterior palatine foramen. 

The pterygoids meet each other at the midline anteriorly, but posteriorly are 
separated by the basisphenoid. They extend backward so far as to exclude the 
bone last mentioned from contact with the quadrates. The lateral border of each 
pterygoid is mostly a sharp free edge. Behind the basisphenoid comes the hasiocctpi- 
tal. It is joined on each side by the exoccipital, and all three of these bones join in 
forming the occipital condyle. From this view is seen also a portion of the par- 
occipital and squamosal. On each side of the basicranial axis are seen foramina 
for the passage of various nerves and blood-vessels. 

Each ramus of the lower jaw is composed of six bones. In front is the dentary, 
furnishing the triturating surface of the jaw, covered above with a horny sheath, and 



■pnuc 





Figs. 3"andj4. Trachemyfscripta. 

3. Skull seen from above. Xi. /r, frontal; _/u, jugal; /iii, parietal; /)aoc, paroccipital; />/r, prefrontal; ^0/, post- 

frontal; pro, prootic; j«, quadrate; jy, squamosal; 50c, supraoccipital. 

4. Skull seen from below. Xi. a/r, alveolar surface of maxilla; 6of, basioccipital; ^jp, basisphenoid; «.voc, exoc- 

cipital; mXy maxilla; paly palatine; paoCy paroccipital; pmx, premaxilla; pro^ prootic; pty pterygoid; jw. art, 
articulation of quadrate with lower jaw; gy, quadratojugal; 55, squamosal; voniy vomer. 

completely co-ossified with its fellow of the opposite side at the symphysis. On the 
lower border of the jaw this bone extends backward nearly to the articulation with 
the quadrate. The upper border of the jaw, behind the triturating surface, is formed 
in front by the coronoid bone; posteriorly by the supraangular. These two bones 
are to be seen both from the outside and from the inside of the jaw. Behind the 
supraangular is a nodular bone that articulates with the quadrate, the articular. 
On the inner surface of the jaw, near the hinder end, are two bones, whose names 
are in dispute. Baur (Anatomischer Anzeiger, xi, 1896, p. 413) calls the lower of 
the two the splenial, the upper the angular. Williston (Science, xviii, 1903, p. 830) 
regards the lower bone as the angular, the upper as a dermal articular. The same 
author has, in his work on North American Plesiosaurs, 1903, page 30, called the 
latter bone the prearticular, and this name is adopted by the present writer. 

The shoulder-girdle of an emyd turtle consists of two bones on each side. One 
of these, the scapula, consists of two slender portions placed at nearly a right angle 
with each other. The longest portion, the proper scapula, the body of the scapula, 



OSTEOLOGY. 7 

extends from the glenoid cavity, of which it furnishes more than half, upward and 
inward, to become ligamentously attacht to the upper end of the first costal plate. 
The other part of this bone extends from above the glenoid cavity inward and 
forward, to be attacht by ligament to the entoplastron. This process has been 
variously interpreted, but here it is regarded as the procoracoid, which has become 
co-ossified with the scapula. It will be called the procoracoid process. For a dis- 
cussion of this subject and a list of writers who have considered it the reader is 
referred to a paper by Max Fiirbringer in Jenaische Zeitschrift, xxxiv, 1900. 
The other bone of the girdle is the coracoid. It starts from the glenoid cavity, 
and proceeds inward and slightly backward, to approach closely its fellow at the 
midline. 

The writer regards the chelonian limb as belonging to a relatively primitive 
type. If the reader will peruse Huxley's chapter on the position of the limbs, in 
his Anatomy of Vertebrated Animals (Appleton's edition, 1872, p. 33), and com- 
pare his statements with what he can see in the limbs of a turtle, he will probably 
agree with the view here presented. The apex of the angle at the elbow, instead of 
being directed backward, is rather directed forward and upward. There is no 
crossing of the ulna and radius. 

The humerus of the emyd is rather strongly bent in the plane passing through 
the axes of the three segments of the Hmb. The head is directed upward. The 
strongly developt tuberosities for attachment of muscles, the radial, or lateral, and 
the ulnar, or medial, are bent toward the lower face of the bone. The ulnar is 
always the larger. At the distal end of the bone, on the anterior or radial side, is a 
passage for the radial nerve, the ectepicondylar foramen. 

Of the two bones of the lower arm the radius is the smaller. It has a shallow 
cavity at the proximal end that meets the articular end of the humerus. Its distal 
end is expanded and articulates with the intermedium and the radiocentrale of the 
carpus. The ulna is the stouter bone, is flattened, has the suggestion of an olecranon 
process, and articulates distally with the intermedium and the ulnare. 

The carpus is simple. Besides the bones already mentioned as belonging to the 
carpus, there is another in the proximal row, on the outer side of the ulna. There 
are 5 bones in the distal row, but sometimes the fourth and the fifth are co-ossified. 
There are 5 metacarpals, each of medium length. The digits are 5 in number, the 
first and the fifth the shortest. The first digit has 2 phalanges, the others 3 each, 
exactly as in the Mammalia. 

The pelvis is broad and short, and each half is composed of 3 bones, all of 
which take part in the formation of the acetabulum. The ilium is expanded antero- 
posteriorly above and is articulated with the outer ends of the sacral ribs. The 
middle of the bone is slender. Each ischium has a posterior process which rests 
on the xiphiplastron and an anterior process which runs forward to join the pubis 
of its side. There is thus produced on each side a large heart-shaped fontanel, 
the ischio-pubic foramen. Each pubis has a lateral process which rests on the 
xiphiplastron. The pubis is prolonged forward considerably, and between the two 
there is a median notch which in life is filled with cartilage, the prepubic; but this 
does not become ossified. 

The femur resembles considerably the humerus; but it is a longer bone and 
there is no perforation corresponding to the ectepicondylar foramen. The head is 
larger and of different form. The trochanters are of about the same size and the 
digital fossa separates them far down. The tihia is a stouter bone than the fibula. 
Its upper end is the larger and presents a large surface for articulation with the femur. 
The lower end has a saddle-shaped articular surface to join the large bone forming 



8 FOSSIL TURTLES OF NORTH AMERICA. 

the first row of the tarsus. The fibula is slender, with the broader end downward, 
articulating with l^he same bone as does the tibia. The bone of the tarsus just 
mentioned is the only one present in the upper row, and is regarded as representing 
three bones that theoretically belong in the upper row, besides the centrale. In the 
lower row of tarsal bones there are five present, all articulating above with the 
large bone of the upper row and distally each with one of the metatarsals. The 
fifth of these bones is peculiarly expanded in the turtles. 

The 5 metatarsals are rather elongated in Graptemys and Trachemys, as are, 
too, the phalanges. In the first digit there are 2 phalanges; in each of the others, 3. 
All the terminal phalanges are invested in horny claws, except the fifth. 

THE CHELONIID/E. THE SEA-TURTLES. 

Some of the salient features of the Cheloniidae will now be described. These 
constitute a family of the Cryptodira, a superfamily to which also the Emydidae 
belong. The Cheloniidae are greatly different in some respects from the Emydidae. 
The shell is composed of the same elements, but many are less completely developt. 
In general, the border of the carapace is excavated in front for the neck; and on 
each side of this for free movement of the fore limbs. Behind, it is pointed, so 
that in form the carapace is somewhat heart-shaped. The costal plates fall short 
of reaching the distal ends of the ribs, as a result of which open spaces, or fontanels, 
are left between the costals and the peripherals. Usually none of the costal plates 
come into contact with the peripherals. The ribs of the costals, however, reach 
these bones and each enters a pit in a corresponding peripheral. In the loggerhead 
(Caretta caretta), for example, rib-ends enter peripherals 3 to 8 inclusive and 
peripherals 10 and 11. In some forms, as Lepidochelys, there are supernumerary 
bones interposed among the neurals, so that the number of these seems to be as 
high as 14. 

The carapace is furnisht with scutes similar to those of the Emydidae. In 
Caretta and Lepidochelys there is a supernumerary costal scute in front of the 
normal first. 

Altho the plastron of these turtles is composed of the same elements as that of 
the Emydidae, some of these are greatly modified. The hyoplastra and the hypoplas- 
tra are not suturally connected with the peripherals of the bridge; nor do the 
plastral bones just named come into contact with their fellows at the midline, so 
that the space between the bones of the right and of the left sides is occupied by a 
great fontanel. On each side there is another fontanel inclosed by the bridge 
peripherals, the outer end of the hyoplastron, and that of the hypoplastron. The 
inner and the outer borders of the two sets of bones last mentioned send out a 
number of digitations into the fontanels. The epiplastra are saber-shaped bones 
which join each other and the entoplastron at the midhne, without jagged sutures; 
and their distal ends are applied to the outer border of the corresponding hyo- 
plastrals. The xiphiplastra are narrow, curved bones that approach each other 
at their distal ends. 

Carapaces and plastra similar to those of the Cheloniidae are found among the 
Thalassemydidas, and to these the reader is referred for illustrations. 

The neck of the Cheloniidae is much shorter than that of the Emydidae and the 
head can hardly be retracted within the shell. In the loggerhead the neck is but 
little more than half as long as the series of dorsal vertebrae. The eighth cervical 
articulates by a synovial surface with the inferior side of the nuchal bone. The 
series of caudal vertebrae is short. 




OSTEOLOGY. 9 

The skull of the Cheloniidae differs in some important respects from that of the 
Emydidae. In order to illustrate this, figures are here introduced giving upper 
(plate I, fig. i), lower (plate i, fig. 2), and lateral (plate 2, fig. i) views of the skull 
oi Leptdochelys kempt Garman. These figures were prepared for Dr. George Baur, 
in 1888, but reverted to the United States Geological Survey, the then director of 
which, Dr. C. D. Walcott, has permitted them to be used here. No figures of 
this species have hitherto been pubUsht. The most interesting feature of the 
skulls of the sea-turtles is the great extent of the bony roof covering the temporal 
region. This roof extends from the orbit to behind the plane of the occipital con- 
dyle. The postfrontal bone, narrow in the emyds, is carried backward nearly to 
the hinder border of the roof. The squamosal sends upward and inward a plate 
that meets a horizontal plate from the parietal, forming a parieto-squamosal arch. 

1 he lower side of the skull is interesting 
chiefly because of the broadening of the triturat- 
ing surfaces of the jaws. The palatal plates of 
the vomer extend backward until they meet 
similar plates from the palatines. The choanae 
are thus thrown much farther toward the middle 
of the skull than in the skull represented by text- 
figure 4. The crushing surfaces of the lower 
jaw are correspondingly widened (plate I, figs. 
3 and 4). In the Thalassemydidae the choanae 

Fig. s.-Care^tta^caretta. Pelvis from ^^^ ^^ ^^^^^ ^^^^ ^^^^^^^ backward, aS may 

be seen by examining the skull of Rhetechelys 
platyops (Cope). There are no posterior palatine foramina. 

In the Cheloniidae the procoracoid process makes an obtuse angle with the body 
of the scapula, and there is a distinct neck between the process and the glenoid 
fossa. The coracoid bone is longer than the scapula and moderately expanded at 
its free end. These bones are represented by fig. 2 of plate 2. 

The humerus of these sea-turtles is strongly modified from the primitive form. 
It is much straighter than that of the Emydidae and has become flattened in the 
plane of the distal end. The head and the radial and ulnar tuberosities have changed 
positions. The head is turned downward and proximad into the plane of the bone, 
while the tuberosities are lifted into this plane, each on its proper border of the bone. 
The radial tuberosity is carried along on the shaft of the bone until it has lost its 
connection with the head. It becomes divided into two parts, one for the deltoid 
muscle, the other for the supracoracoid. Fig. 3, plate 2, represents the humerus of 
Lepidochelys as seen from above; fig. 4, as seen from below. 

Relatively to the humerus, the radius and the ulna are shortened, the ulna 
more than the radius. In the carpus the radiale remains small, the intermedium 
and the ulnare are enlarged and flattened, while the centrale is distinct. There are 
five bones in the distal row, one articulating with each metacarpal. The third and 
the fourth may be co-ossified. On the ulnar side of the carpus there is a large flat 
bone assisting to broaden the carpus. It may be regarded as the pisiform. 

The second, third, and fourth digits are greatly elongated, the bones flat- 
tened, and all are bound together in a mass of muscles and skin to form an undivided 
oar. The first, and in some cases the second, digit is provided with a claw. 

The pelvis of the Cheloniidae is broad and deprest (fig. 5). The ilia are short; 
the upper end is slender and turned backward and the axis of the bone is nearly 
in the plane of the pubes. The latter bones are broad. Between the two, at the 



10 FOSSIL TURTLES OF NORTH AMERICA. 

midline in front, there is a deep notch, filled in life by the prepubic cartilage. The 
lateral processes are broad. The ischia are without posterior lateral processes, and 
they are not connected with the pubes on the midline by bone; thus the ischio- 
pubic foramina unite into one in the prepared skeleton. 

The femur, which in the emyds is longer than the humerus, is, in the sea-turtles, 
shorter than the latter element. The shaft is not so straight as is that of the humerus 
and the head is not so much deflected toward the axis of the shaft. The trochanters 
differ considerably in size and the digital fossa does not descend far between them. 
The tibia and the fibula are relatively stout bones. While in the emyds described 
above, the two upper segments of the fore limb are considerably shorter than the 
corresponding segments of the hinder, the reverse is true in the Cheloniidae. Figs. 
5 and 6 of plate 2 represent the femur of Lepidochelys. 

The hinder foot of sea-turtles is, compared with the fore foot, greatly reduced. 
In Caretta the hinder foot, including the tarsus, is only about half as long as the 
fore foot. There are 2 bones in the first row of the tarsus, 5 in the second row. 

THE TRIONYCHOIDEA. THE SOFT-SHELLED TURTLES. 

We will give our attention now to members of another superfamily, the Tri- 
onychoidea, popularly known as soft-shelled turtles, sometimes as mud-turtles, or 
river turtles. The two last-mentioned names are, however, often applied to other 
groups of turtles. 

In these, as in other turtles, there is a carapace and a plastron; but they differ 
greatly in appearance from those of the emyds. The whole body is greatly deprest. 
For illustrations of these portions of the shell the reader may consult the figures of 
the fossil species on succeeding pages. The carapace is usually composed of neurals, 
7 or 8 in number, 7 or 8 pairs of costals, and a nuchal bone. Only in one genus, 
Trionyx (EmyJa Gray), including two Asiatic species, are there any suggestions of 
peripherals. The costal bones are closely articulated to their neighbors and the 
contiguous neurals; but often these costals do not extend to the ends of the ribs; 
or, if they do, it is only in very advanced age. In Hfe the periphery of the shell is 
surrounded by a rim of dense and flexible connective tissue, terminating all round 
in a sharp edge. It is this rim that has suggested the name soft-shell. 

The whole upper surface of the carapace is ornamented with a network of 
ridges which inclose pits of various forms. The size and arrangement of the ridges 
and pits vary in the different species. There are never any traces of horny scutes, 
the outer skin always remaining soft. 

The plastron in some respects resembles that of the sea-turtles, inasmuch as 
there are median and lateral fontanels and the connection with the carapace is 
a ligamentous one. The hyoplastra and the hypoplastra are furnisht with median 
and lateral digitations. Of the median digitations one belongs to each hyoplastron 
and is directed forward and inward, to come into contact with the entoplastron. 
Two belong to each hypoplastron, one being directed toward that of the opposite 
side, the other toward the xiphiplastron. Of the lateral digitations one set is 
directed from each hyoplastron forward and outward, the other from the hypo- 
plastron backward and outward. The hyoplastron and the hypoplastron of each 
side are closely sutured together, in some cases co-ossified. 

The entoplastron is V-shaped, the apex being directed forward, an arm resting 
against the hyoplastron of each side. The epiplastral bones are slender and curved, 
usually not in contact with each other at the midhne. They differ from these 
bones in all other turtles in being excluded from contact with the hyoplastra by 
the arms of the entoplastron. 



OSTEOLOGY. I I 

The xiphiplastra are usually more or less curved bones, whose anterior ends 
interdigitate with the hypoplastra, while their posterior ends meet at the midhne. 

In some cases the plastral bones are smooth and devoid of ornamentation. In 
many other cases there are developt on their lower surfaces patches of more super- 
ficial bone, the callosities. These callosities are sculptured into pits and ridges, 
somewhat like the bones of the carapace, but the pattern may be different. Each 
callosity may occupy but a small part of the bone developing it or it may extend 
over the whole bone. The callosities are more extensive in the Cretaceous and 
Tertiary species than in those now existing. 

The best description of the plastral bones of living Trionychidae has been 
publisht by Dr. Friedrich Siebenrock (Sitzungsber. Akad. Wiss. Wien, cxi, 1902, 
pp. 807-846). 

In the Plastomenidae the median fontanels are filled up; and the whole lower 
surface of the hyoplastra, hypoplastra, and the xiphiplastra is sculptured. 

The neck of the soft-shelled turtles is long and slender, and, hke that of the 
Cryptodira, it bends most freely in a perpendicular plane. In a specimen of Platy- 
peltis spinifera at hand all the centra are convex in front, concave behind, except 
that the hinder end of the eighth is reduced to a thin edge. This cervical is con- 
nected with the first dorsal almost wholly by the zygapophyses. 

The skull of the soft-shelled turtles presents many distinctive features. Fig. 
I, plate 3, represents that oi Platypeltis ferox, a Florida species, seen from above; 
fig. 2, plate 3, the same skull as seen from below. The skull is elongated and pointed 
in front. The posterior region is notable for the three large backwardly directed 
processes, the supraoccipital and the two squamosal processes. Of the temporal 
roof there is no part except the postorbital and the zygomatic bars. The prootic 
extends much in front of the articulation of the lower jaw. The hinder border of 
the pedicel of the quadrate is closed behind the stapes, so that this occupies a canal, 
instead of a notch. The premaxillae have coalesct into a single small bone. Seen 
from below, the skull presents in front a median prepalatine foramen and the two 
choanae. Altho the latter open rather far backward, they are not underfloored by 
vomerine, palatine, and maxillary plates. The triturating surfaces of this species 
are rather broad. The vomer is always small. The palatines meet throughout 
their length at the midline, and posteriorly they articulate with the basisphenoid. 
The pterygoids are broad, run backward alongside the basioccipital, and do not 
meet on the median line. The basioccipital and the exoccipitals all take part in 
the occipital condyle. The paroccipital is a large bone. 

The lower jaw (plate i, fig. 5) is composed of the same elements as that of the 
emyds. The coronoid bone is large and the angle of the jaw projects considerably 
behind the articulation with the quadrate. 

The hyoid apparatus is strongly developt. 

In order to accommodate itself to the flattened form of the body, the scapula is 
directed from the glenoid fossa upward, forward, and inward, making an angle of 
about 50 degrees with the procoracoid process (plate 3, fig. 3). The latter is slightly 
expanded toward its distal end and flattened. The coracoid is broad and flat and 
somewhat saber-shaped. 

The humerus (plate 3, figs. 4, 5) is a stouter bone than that of the emyds above 
described, and it is less neatly modeled. The proximal tuberosities, the radial and 
the ulnar, are larger, with a broader fossa between them. The ectepicondylar passage 
is a groove. The radius is half the length of the humerus; the ulna is still shorter. 

The fore foot is as long as the humerus, a condition due to the elongation of 
especially the median digits. The three on the radial side have claws, the others 



12 FOSSIL TURTLES OF NORTH AMERICA. 

do not. The phalangeal formula of the first three digits is 2, 3, 3, as in Emydidae. 
The fourth may have 4, 5, or 6, while the fifth finger may have 3 or 4 phalanges. 

The pelvis resembles much that of the Cheloniidae, but the opening representing 
the united ischio-pubic foramina is larger. The ilium is short and slender and 
the upper end is turned backward. The ischia have short posterior processes. 

The femur (plate 3, figs. 6, 7) is slightly longer than the humerus, which it 
resembles considerably. It may be distinguisht by its having no ectepicondylar 
groove and by the narrower, more elongated, head. The trochanters are wide 
apart and wholly separated by the interdigital fossa. 

The tibia is a stout bone nearly three-fourths as long as the femur. As in other 
turtles, the tibia is a slenderer bone. The hinder foot is still more elongated than 
the anterior, that of P. spinifera being more than a third longer than the femur. 
The first three digits have the same number of phalanges as other turtles; that is 
2, 3, 3. The fourth digit may have 4 or 5 phalanges; the fifth, 2 or 3. The first 
three have claws. 

THE PLEURODIRA. THE SNAKE-NECKT, OR SIDE-NECKT TURTLES. 

It is necessary to make some observations on the osteology of the members of 
another superfamily, the Pleurodira. The shell is composed of the same elements 
as in the emyds and often presents no important differences from that of the latter. 
There are genera in which the neurals are reduced in number and a few in which 
these bones have been wholly supprest. In a few living genera and in some 
that are extinct there is present a pair of bones, unknown in the Cryptodira and 
Trionychoidea, the mesoplastrals, interposed between the hyoplastrals and the 
hypoplastrals. In Pelustos (Sternothcerus) these bones join across the plastron. 
In Pelomedusa they are small triangular bones occupying the middle of the bridge 
only. The same bones occur in the species of Ba'ena; and the reader may consult 
the figures under that genus. 

The shell of all Pleurodira differs from that of other turtles in forming sutural 
connections with the pelvis. The eighth costal plates develop each a sutural surface 
for the upper end of the ilium. On each of the xiphiplastrals are two sutural scars, 
the anterior for union with the pubis, the posterior for union with the ischium. 
On other pages will be found figures of the species of Taphrosphys, which represent 
these articulations. In the Pleurodira there is probably always an intergular scute 
present. Sometimes the gulars meet in front of it. 

The cervical vertebrae are, as in all turtles, 8 in number, but they differ greatly 
from those of the Cryptodira and of the Trionychoidea. In contradistinction to the 
neck of the latter turtles, that of the Pleurodira is constructed for free flexure in a 
horizontal plane. This is effected by having the centra joined by ball-and-socket 
joints and by having the zygapophyses of the two sides placed close together and 
high above the centra. A description of these vertebrae is given from the neck of 
Hydromedusa tectifera. 

The neck is nearly a third longer than the dorsal series of vertebrae. The first 
cervical, unlike that of the other superfamilies, has all the elements consoHdated 
and is two-thirds as long as the longest. As regards the articular ends of the centra 
we have the following: The first and the seventh are concavo-concave; the second, 
third, and fourth are convexo-concave; the fifth and the eighth are convexo-convex; 
the sixth is concavo-convex. All the cervicals possess well-developt transverse 
processes, with broad bases. Along the lower side of the centrum of each runs 
a sharp crest. The postzygapophyses of the first two vertebrae are separated by 



OSTEOLOGY. 



^3 



only a slight notch; all the others have coalesct. The prezygapophyses are close 
together, but have not coalesct. Those of the eighth are very small, thus greatly 
different from those of the members of the other superfamilies. 

In some of the other Pleurodira the intercentrum and the odontoid process of 
the first cervical are distinct from the arches. In the Pelomedusidae only the second 
cervical is convexo-convex; all the others concavo-convex. 

In none of the Pleurodira is the neck withdrawn into the shell as it is in the other 
turtles, but is bent sideways and brought under the projecting borders of the shell. 
In harmony with this action, the anterior bones of the carapace and of the plastron 
often project farther than in other turtles. 

The skull of the Pleurodires offers many peculiar structures. That of Hydrome- 
dusa may first be considered. This skull is long and very flat. There are distinct 
nasal bones. The prefrontals do not send down processes to the vomer. There is a 
postorbital arch, but no zygomatic arch. At the rear there is a very slender palato- 
squamosal arch. Seen from above the whole upper surface of the pterygoids and the 
whole temporal fossae are exposed to view. There is no ridge projecting outward 
from the parietal over what may be called the suprapterygoid fossa, as in other 
turtles; nor does the prootic project forward over this fossa. The fossa just men- 
tioned is bounded outwardly by the upturned outer border of the broad pterygoids. 
The premaxillas are small. The supraoccipital spine is extremely short. 

Fig. 6 represents the skull seen from below. The 
triturating surfaces of the upper jaw are very narrow. 
The choanal openings are very large and are separated 
by the splint-like vomer, which comes into contact with 
the pterygoids. The latter bones separate widely the 
small palatines. Behind the latter bones are the posterior 
palatine foramina. The pterygoids are greatly developt 
anteriorly and laterally. They are in contact on the mid- 
line in front, but for more than half their length the 
basisphenoid bone comes between them. The pterygoids 
are abbreviated behind, so that they permit the quadrates 
to join the basisphenoid. This arrangement is character- 
istic of the Pleurodires and distinguishes them from all 
other turtles. The quadrate is notcht behind for the 
passage of the stapes. 

The lower jaw is slender and the coronoid processes 
are low. The articular furnishes a ball for articulation 
with the quadrate. There is present what Baur called 
a presplenial, but which is here regarded as the true 
splenial, a bone absent from most turtles. 

The hyoid apparatus is greatly developt, but need not 
here be described. 

The scapula is a strong bone. The procoracoid 
lation of quadrate with lower jaw; process makes Icss than a tight angle with the body of 

vom, vomer. ' , , j-, , ~ . ~ . , . ■^. 

the bone. Between the two portions, m the angle, is a 
sharp crest. The glenoid fossa is at the end of a long neck. The coracoid is 
relatively short, much bent in a horizontal plane, and expanded at the free end. 
The humerus resembles that of the emyds in most respects. The ulnar and 
radial tuberosities are somewhat larger, the ulnar ascending slightly above the head, 
the radial descending lower than in the emyds. The ulna has no suggestion of an 




Fig. 6. — Hydromedusa. Skull 
from below. Xj. 

bocy basioccipital; hsp, basisphenoid; 
exoCj exoccipital; mr, rnaxilla; pa^ 
parietal; pal, palatine; paoCy paroc- 
cipital; pmXj premaxilla; />/, ptery- 
yoid; qu^ quadrate; qu. art, articu- 



14 FOSSIL TURTLES OF NORTH AMERICA. 

olecranon. The tarsus and digits do not differ enough from those of emyds to 
require further notice here. 

The pelvis of Hydromedusa differs greatly from that of the emyds and triony- 
chids. The ilia are much expanded and triangular at their upper ends, and have 
become joined by a rough suture with the eighth costals. The lateral processes of 
the pubes are stout and are sutured to rough surfaces on the xiphiplastra. The 
anterior branch of the pubis is slender and joins its fellow at the midline. The 
ischia are stout bones, sutured to the hinder border of the xiphiplastra. The lower 
portion of each ischium expands into a great lateral process, which runs forward 
and inward to join the one from the other side, the whole length of each process 
being sutured to the xiphiplastron. There is no bony union of the pubes and the 
ischia along the median line. As shown by Baur (Jour. Morphology, iv, 1891, p. 
351) there is, in many Pleurodires, a greatly lengthened prepubic cartilage. It is 
to be compared with the prolongation forward seen in the pubes of species of 
Ba'ena and Chisternon. 

The hinder limb does not differ notably from that of the emyds. 

Illustrations are here furnisht of the skull of Podocnetnis expanse, another 
Pleurodire, the structure of which in many respects strikingly differs from that of 
Hydromedusa. From plate 4, fig. I, it will be seen that the temporal region is 
nearly as completely rooft over as is that of Lepidochelys (plate i, fig. i). There 
are no nasal bones and the supraoccipital spine is long. In one feature of the 
temporal roof this turtle is different from Lepidochelys. In the latter the postfrontal 
bone extends backward nearly to the hinder border of the roof; in Podocnemis 
the postfrontal bone is very small and its place in the roof is mostly occupied by the 
quadratojugal, which rises over the squamosal, excluding the latter from contact 
with the parietal (plate 4, figs. 1-5). 

Fig. 2, plate 4, represents a palatal view of the same skull. The premaxillae are 
of considerable size. The vomer is absent. The triturating surface of the maxilla 
is broad and furnisht with ridges. The choanae are restricted. The palatines are 
broad and meet throughout their length at the midline. The pterygoids, too, are 
broad, little separated mesially by the basisphenoid, and the outer border of each is 
turned upward into a scroll-like process. The articular surface of the quadrate, 
for the lower jaw, is seen to be concave. 

Fig. 5, plate 4, shows the same skull viewed from the side. 

The lower jaw (plate 4, figs. 3, 4) presents a ball-like articular surface for the 
quadrate. In front of this are seen the angular, the prearticular, the splenial, and 
the dentary, the latter consolidated with its fellow at the symphysis and furnisht 
above with a broad and ridged triturating surface. On the outside of the hinder half 
of the ramus is the supraangular. 

THE DERMOCHELYID^E. THE LEATHERBACK TURTLES. 

It is necessary now to describe in brief terms the skeleton of the leatherback 
(Dermochelys coriacea), one of the most extraordinary of turtles. It attains a great 
size and is the most thoroly aquatic turtle that is known (fig. 7). Figures of all 
portions of the skeleton may be found on the plates illustrating a paper by Paul 
Gervais on this turtle, publisht in the Nouvelles Archives du Museum d'Histoire 
Naturelle de Paris, volume viii, 1872. 

The ribs of this turtle, instead of being consolidated with costal plates that 
unite edge to edge to form a carapace, are wholly free from one another. The first 
rib is wholly free from the second, the tenth from the ninth. The only thing that 



OSTEOLOGY. 



15 



may be supposed to represent the costal plates is the irregular border of the some- 
what expanded ribs. Of the other elements entering into the carapace of an emyd 
or a pleurodirid, the leatherback possesses only the nuchal bone. 

But the leatherback has a carapace peculiar to itself. This is composed of a 
layer of thin, polygonal bones which are buried in the thick skin of the animal. Of 
these bones there are 7 rows of larger ones, that appear in the living animal as so 
many sharp dorsal keels. One of these rows is along the midline; three run along 
each side. In front, this layer of mosaic-like bones overHes the nuchal. Smaller 
bones fill up the spaces between the rows. 

On the inferior side of the turtle there are 5 rows of similar bones, but the spaces 
between the rows are not so completely filled as on the upper side. Beneath the 
skin which supports these rows of bones there is a ring of elongated bones which 
represent the plastron of more normal turtles. These represent the epiplastra, 
the hyoplastra, the hypoplastra, and the xiphiplastra. The entoplastron is missing. 
All these bones are slender and thin, and they surround a vast fontanel. 




Fig. 7. — Dermochelys coriacea. Greatly reduced. 

The cervical vertebrae differ in no important respect from those of Caretta, and 
the neck is equally short. The dorsals are ten in number and immovably joined to 
those in front and behind by rough articular ends. The neural arches are moved 
forward, so that each articulates about equally with its own centrum and that in 
advance. They are somewhat expanded above, but do not come into contact with 
plates from the ribs. In fact, these plates are extremely vestigial. There are two 
sacral vertebrae, whose ribs articulate with the iha; and there are about twenty 
caudals. 

The skull at first glance presents many resemblances to that of members of the 
Cheloniidae. The temporal roof extends backward as far as the occipital condyle. 
The postfrontal and the jugal are large, and the squamosal joins the parietal. 
The supraoccipital spine is short. The prefrontals extend backward to beyond the 
orbits. The external nares look forward and strongly upward. The maxillae are 
not strongly developt; and they have hardly any triturating surfaces. The choanae 
are placed far forward and open directly into the roof of the mouth. A spHnt-like 
vomer separates them, and extends backward to the pterygoids. The palatines are 
broad, and they reach forward nearly to the vomer, sometimes coming into contact 
with it. Thus, they bound the choanae outwardly. The pterygoids join on the mid- 
line for a short distance only in front; otherwise, they are widely separated by the 



l6 FOSSIL TURTLES OF NORTH AMERICA. 

basisphenoid and the basioccipital; they shut off the latter bones from contact 
with the quadrate. The inner borders of the pterygoids lie upon the upper side of 
the basisphenoid. 

In one important respect the leatherback and its few fossil relatives differ from 
all other turtles. This is in the fact that the parietal bone does not send downward, 
in front of the exit of the trigeminal nerve, a plate to join the pterygoid. 

The occipital condyle remains cartilaginous. The pedicel of the quadrate is 
slender and directed strongly forward. The lower jaw is feebly developt and fitted 
for soft food. The articular remains cartilaginous. The angular and the supra- 
angular are short, as seen from the outer side of the jaw, but are prolonged on the 
inner side. The prearticular and the coronoid are not present. 

The parts of the scapula are short and thick. The procoracoid process makes 
an obtuse angle with the body of the bone. The coracoid bone is about twice as 
long as the process mentioned, and the free end is somewhat expanded and flattened. 

The humerus is a massive bone and much flattened. The general form is that 
of the humerus of Leptdochelys, but the radial tuberosity is brought down to a 
point more than half-way from the head of the bone to the distal end. The end 
for articulation with the ulna and the radius is very broad, and nearly semicircular 
in outline. The ectepicondylar passage is a foramen wholly in the bone, about the 
middle of its width. 

The radius and the ulna are stout bones of about equal length and only about 
half as long as the humerus. The carpus has 2 bones in the first row, a centrale, 
5 bones in the second row, and a large pisiform. Sometimes the fourth and the 
fifth distal carpals are co-ossified. The digits have the normal number of pha- 
langes; that is, 2 in the thumb and 3 in each of the others. The second, third and 
fourth digits are greatly elongated, being twice the length of the humerus measured 
from the head. None of the digits bears a claw. All are bound together in a com- 
mon envelope of skin to form a powerful flipper. 

The pelvis is in many respects different from that of the Cheloniidae. The 
form of the ilium and its position with respect to the pubis do not differ greatly 
from those of the ilium of Caretta, but the ischia are broader fore and aft than in 
Caretta. The pubes are connected along the midline for a much greater distance 
than in the Cheloniidas. Posteriorly they approach the ischia, so as nearly to join 
them, the interspace being filled by cartilage. The ischio-pubic foramina are 
extremely small and nearly separated in the midHne. The lateral processes are 
very large, extending outward and forward, so that at their extremities the pelvis 
is twice as wide as it is across the narrowest part of the pubes. Each process 
terminates in a large plate of cartilage. There is likewise a large spatulate prepubic 
cartilage. 

The hinder limb is reduced in size, as in the Cheloniidae, and offers differences 
only in detail. 



MODIFICATION IN TURTLES. 1/ 

ON THE AMOUNT OF MODIFICATION UNDERGONE BY TURTLES 
SINCE THEIR EARLIEST APPEARANCE. 

On preceding pages a brief exposition has been presented of the principal 
structures shown in the skeletons of turtles of various groups. It is now intended 
to consider the differences of structure from another point of view, that of determin- 
ing the amount of differentiation these animals have suffered since their earliest 
appearance, especially as compared with the changes undergone by other orders of 
reptiles. It is generally supposed that turtles have been unusually conservative in 
their changes; that, as in their movements so in their development, they have 
progrest slowly. We are to inquire to what extent this impression is true. 

Let us first consider the shell, that part which is most often found preserved in 
the rocks and the part which is regarded as most characteristic of turtles. The 
theory accepted by the writer is that originally the upper side of the body was 
protected by a rim of peripheral bones, a median row of neural bones, and eight 
pairs of bony plates which overlay the ribs and had possibly in the earliest turtle 
coalesct with them, probably joining one another by their contiguous edges; and 
that in addition to the bones enumerated, subdermal in their position, there was a 
more superficial layer of bones, dermal in position and forming seven longitudinal 
zones, a median or vertebral zone, two costal, two supramarginal, and two marginal 
zones. The plastron was formed of at least eleven subdermal bones, while super- 
ficially there were found five zones of dermal bones, a median and two lateral on 
each side of it. Starting with this outfit, the vast majority of turtles have wholly 
or almost wholly divested themselves of the dermal layers and have acquired a soHd 
shell composed of the subdermal bones. On the other hand, the leatherback 
turtle, Dermochelys, appears to have retained the dermal and to have almost wholly 
surrendered the subdermal bones, for the costal plates now form only unimportant 
fringes on the ribs; the peripherals and neurals are wholly gone; the nuchal 
is reduced; and the plastral bones are only eight slender rods. As regards the 
carapace, Dermochelys possesses little that is homologous with that of most other 
turtles. 

If we view the modifications undergone by the shell within the group known as 
Thecophora we find that they are extensive. We can hardly doubt that the primi- 
tive turtles possest a pair of mesoplastral bones; and yet we know that all turtles 
have discarded these, except a few of the Pleurodira. Within the latter super- 
family the shell has not suffered remarkable modifications. Nevertheless, most 
of the genera have no mesoplastra. In some the plastron is connected with the 
carapace ligamentously, while in others strong axillary and inguinal buttresses rise 
from the plastron and articulate with the inferior surface of some of the costals. In 
all, the hindermost costals have contracted a sutural union with the ilia. In a 
considerable number of genera the neurals have become wholly supprest. In 
Pelusios (Sternothcerus) there is a hinge behind the hyoplastra. 

In the superfamily Trionychoidea the shell has undergone extensive reduction. 
No traces are known of the original dermal layer of bones. The neurals and the 
costal plates are retained; but the latter show retardation in their development, 
attaining the distal ends of the ribs not at all or only at a late date in life. The 
peripherals are wholly missing, except perhaps in the genus Trionyx {Emyda Gray). 
In the plastron we never find mesoplastra and all the bones are more or less reduced. 
In the great majority of cases there are fontanels on the midline and at the bridges. 
The form and relations of the entoplastron and the epiplastra are very different 
from those of other turtles, but homologies are easily traced. 



l8 FOSSIL TURTLES OF NOR! H AMERICA. 

It is in the extensive group of Cryptodira that we meet with the greatest number 
of what may be regarded as the minor modifications of the shell. If we except 
Toxochelys, no known Cryptodire shows more than vestiges of the ancient layer 
of dermal bones. In some, as Protostega and Archelon, of the Upper Cretaceous, 
the costal plates are nearly as much reduced as in Dermochelys. In these and a 
number of other genera of Cretaceous turtles the peripherals are slender, but they 
persist. Probably the neurals are never wholly absent. The elements of the 
plastron degenerate in some cases; but, with the exception of the entoplastron of a 
few genera, all persist. 

It is in this group that we discover the greatest variety in the forms of the shell, 
ranging in convexity from much deprest to highly vaulted and bombous, and from 
relatively long and narrow to a breadth greater than the length. There may be 
one or more carinae on the carapace and its free borders may be smooth or variously 
notcht or rolled. 

In some genera of Cryptodira, as the snappers and the sea-turtles, there are 
extensive fontanels between the distal ends of the ribs and others at the sides and 
the middle of the plastron. In most Cryptodira the bones are solidly articulated, 
abrogating all fontanels. In the snappers and the sea-turtles again, the plastron 
is only ligamentously joined to the carapace. In other genera, as Batagur, Hardella, 
and Echmatemys, the plastron sends up powerful axillary and inguinal buttresses to 
the inside of the carapace. Between these extremes there are all gradations. 

Among the Cryptodira there is a great variety of hinges between portions of the 
shell. In Cyclemys there is a hinge between the hyoplastron and hypoplastron, 
and both these bones are sutured to peripherals. In Terrapene there is a similar 
hinge, with the bones only ligamentously joined to the carapace. In the extinct 
genus Ptychogaster there is a sliding joint between the hypoplastron and the contig- 
uous peripherals. In Kinosternon there is a hinge between the epiplastra and the 
hyoplastra, and another between the hypoplastra and the xiphiplastra. In Kinixys 
there is a hinge in the carapace between the fourth and the fifth costal plates. 

Attention may be called to the modifications of the neurals and the costal plates 
in Testudo. The neurals are alternately large and octagonal and small and quadrate. 
The costals are truncated wedges, placed so that broad and narrow ends alternate 
both next the neurals and the peripherals. 

There are numerous interesting modifications in the number, form, and disposi- 
tion of the horny scutes of the shell among the turtles. There are supposed to have 
been originally 12 rows, or zones, of these scutes, corresponding to the 12 rows of 
dermal bones of Dermochelys and the ancestral turtle. A scute coincided with each 
bone. In each row some scutes grew at the expense of the others and persisted even 
after the disappearance of its supporting bone. Whole rows of the scutes dis- 
appeared, as the supramarginals and the median plastral row of most turtles. The 
supramarginals are represented in Macrochelys by a few scutes over the bridges. 
The anterior and posterior ends of the supramarginal series are found in the Triassic 
Proganochelys. Many genera furnish the inframarginals, as nearly all the Derma- 
temydidae. In the Emydida; all have vanisht except one in the axillary notch and 
another in the inguinal. In the Baenidae, the Dermatemydidae, and the Pleurodira 
we find the middle plastral row represented by the intergulars. Archa-ochelys 
Lydekker and Polythorax Cope present more posterior scutes of this row. Between 
zyoungDermochelys with its 12 rows of epidermal scutes, with many in each row, 
and Terrapene, with only 7 rows, there are many and interesting stages. 

But the Trionychidae carry the reduction of the scutes to the extreme, for none of 
the whole superfamily shows any traces of these whatever. In various species of the 



MODIFICATION IN TURTLES. IQ 

Other groups the boundaries of the scutes are not visible on the shells; but in most 
of these cases the scutes were probably very thin and their edges did not impress 
the bone. In the living Carettochelys and the extinct Pseudotrionyx, both Crypto- 
dires, there are no scutes. 

The principal characters which belong to turtles in general will be given on a 
succeeding page. Besides these common characters, others that have been lost or 
modified were possest by the more primitive members of the order. Of these may 
be mentioned the presence of nasals, of lachrymals, and of an extensive roof over the 
temporal region. The presence of this roof in the skulls of the older turtles is so 
general, perhaps rather so universal, that its primitive nature can hardly be doubted. 
Its frequent presence in the skulls of the lower forms of living turtles and its general 
absence in the case of the higher forms confirm this conclusion. This roof must have 
been inherited from the Cotylosaurian ancestors of the order. Otherwise, we must 
suppose that it was developt during the history of the chelonians and again lost by 
most of them. It appears obvious that the roof has been reduced in proportion to the 
elongation of the neck and the ability to withdraw the head beneath the shell. In 
Dermochelys and the Cheloniidae the roof extends backward as far as the occipital 
condyle; and all these turtles have short necks and can furnish beneath the shell 
little protection to the head. In the snappers the roof is moderately developt; in 
most of the Emydidae and all the Trionychoidea the roof is reduced to a narrow 
postorbital bar and to a zygomatic bar. In some species of Terrapene and in some 
other genera the zygomatic bar is missing. While in some Pleurodira, as Podocnemis, 
the roof is wide, in others nothing is left but the postorbital bar. Several genera 
possess a parieto-squamosal arch (Rhtnemys, Hydraspis, Hydromedusa). Dr. 
George Baur showed the various ways in which these results have been attained. 
In the Cryptodira the roof has been eaten away from behind forward and in front 
of the tympanic cavity, severing first the union of the parietal and the squamosal, 
then that of the postfrontal and the squamosal, and finally in rare cases that of the 
jugal and the quadratojugal. In the Pleurodira the reduction has followed the 
reverse course, beginning in front of the tympanic cavity and moving upward and 
backward. In several genera of Pleurodira there has been left only a very narrow 
parieto-squamosal bar; in others, not even this. In all cases the removal of the 
bone has begun at one border or the other of the bone and never by the formation of 
fontanels in the roof. 

In no other order of reptiles do we find such enormous variation in the character 
of the temporal roof. Superfamilies and families of turtles present modifications 
that would characterize orders of other reptiles. 

The palatal region offers variations in structure that are of wide range. Primi- 
tively the choanae opened in the front of the mouth one on each side of the narrow and 
shallow vomer. A broadening of the triturating surfaces of the jaws required that 
the choanae be pusht backward. This was accomplisht by the development of 
a median descending plate of the vomer, which spread laterally and joined palatal 
plates from the maxillae, the palatines, and sometimes even from the pterygoids. 
Thus a floor was formed beneath the nasal channels, carrying these backward 
sometimes more than half-way to the occipital condyle. The process is similar to 
what occurred in the order of Crocodilia; only, in the most primitive known forms 
of the latter the choanae are placed immediately in front of the pterygoids, while in 
the most advanct forms the choanae are in the rear of these bones. These differences 
were regarded by Huxley as sufficient to justify the recognition of two groups of 
crocodiles, the Mesosuchia and the Eusuchia. Variationsof greater extent among the 
turtles characterize famiUes only or even genera. 



20 FOSSIL TURTLES OF NORTH AMERICA. 

The jaws have suffered extensive modifications. In the less differentiated 
turtles the cutting-edges of the jaws are low and the triturating surfaces narrow. 
The cutting-edges may become deep, without increase of the width of the triturating 
surfaces and vice versa. For an illustration of great width of the grinding surfaces 
the reader is referred to the species Rhetechelys platyops (Cope). 

The lower jaw becomes modified to correspond with the upper jaw. The rami 
of that of Toxochelys latiremis are narrow and slender; while those oi Erquilinnesia 
are broad, flat, and fitted for crushing hard objects. 

The vomer, which is always developt in the Cryptodira, the Trionychoidea and 
some of the Pleurodira, is wholly missing in some forms of the latter superfamily. 

There is great variation in the pterygoids. The primitive condition appears to 
be essentially that now found in the Cryptodires in which these bones are of 
moderate width and extend backward so as to exclude the quadrates from contact 
with the basicranial bones. This condition exists also in the Amphichelydia and 
the Trionychoidea. In the Pleurodira the pterygoids have become shortened poste- 
riorly, so as to let the basicranial bones join the quadrates. They have also become 
expanded, and the outer edge is rolled up in a scroll-like manner. 

The necks of turtles furnish us with many interesting features. There is 
no doubt that in the early turtles the neck was short, perhaps less than half as long 
as the dorsal series of vertebrae. Doubtless the lengthening has been brought 
about to facilitate the prehension of food, but it has had other consequences. In 
some species of each of the superfamilies of Thecophora the neck is considerably 
longer than the dorsal series, but it has retained its primitive shortness in Dermo- 
chelys and the other sea-turtles. The elongation of the neck is never due to any 
increase in the number of vertebras, but to the lengthening of the individual vertebrae. 

The most important modifications of the cervical vertebrae are to be found, not in 
their mere elongation, but in the structure of their parts. Originally, as we learn 
from Glyptops pUcatulus, the vertebral centra were all biconcave. In Ba'ena and 
Chisternon we find the beginnings of differentiation in the articular ends of the 
centra. The highest stage of differentiation is perhaps to be found in species of 
Testudo. In Testudo radtata, of Madagascar, the second cervical is convexo- 
concave; the third and the eighth convexo-convex; the fourth, fifth, and sixth, 
concavo-convex; the seventh, concavo-concave. The joint between the sixth and 
seventh and that between the seventh and the eighth are elongated from side to side 
and divided into right and left portions, forming true ginglymoid articulations. 
Variations of this arrangement are found even within the genus Testudo. Modifi- 
cations and less differentiated stages are to be found in other famiUes of Cryptodira. 

The necks of the Trionychoidea are usually greatly elongated and the vertebrae 
are essentially as in the Cryptodira. The Pleurodira do not possess ginglymoid 
joints, but in at least one genus there are saddle-shaped vertebral articulations, as 
in birds. 

In the development of the mechanisms permitting flexion of the neck two distinct 
paths were followed, the Athecae, the Cryptodira, and the Trionychoidea taking the 
one, the Pleurodira the other. The goal reacht in each case is very different from 
that attained in the other. In the first case, the neck is bent in a perpendicular 
plane ; in the case of the Pleurodira, in a horizontal plane. As the neck of members 
of the Cryptodira and Trionychoidea lengthened, the head began to be withdrawn 
within the shell for protection. In the case of the Pleurodires the neck is bent 
laterally, and it and the head are protected by the projecting borders of the shell. 
If the neck is so long that it would carry the head beyond the axilla it is bent first 
in one direction, then in the other. 



MODIFICATION IN TURTLES. 21 

To permit these different modes of flexion the mechanical arrangements must 
be different. In the Cryptodires and the trionychids there are ginglymoid joints 
at the base of the neck, facihtating bending in a perpendicular plane. The neural 
arches are low, with the zygapophyses wide apart, favoring motion in the vertical 
plane, restricting it in the horizontal. In the Pleurodires the arches are high, the 
zygapophyses close together, often confluent, and at least one end of most of the 
centra semiglobular, arrangements aiding motion in a horizontal plane. 

It is doubtful whether there is another group of vertebrates that possesses so 
many modifications of the cervical vertebrae as are found in the turtles. 

There has occurred a considerable amount of modification in the pelvis of these 
reptiles. As shown by Glyptops, of the Jurassic, and Ba'ena and Chisternon, of the 
Bridger, the pelvis was not originally suturally joined to the shell. In both the 
Cryptodires and the trionychids the pelvis has retained its original freedom. In 
the Pleurodires the ilia effected, before the close of the Cretaceous, strong sutural 
connections with the hindermost costal plates; while the ischia and the pubes 
became closely sutured with the xiphiplastra. 

In the Amphichelydia the ischia and the pubes are joined along the midline by 
a bar of bone, thus defining right and left ischio-pubic foramina. In the Baenidae, 
so far as known, and possibly in Glyptops, the prepubic process was strongly 
ossified. In the Emydidje and the Testudinidae the ischio-pubic bar is ossified; but 
in the Cheloniidas and the Trionychoidea this region is wholly cartilaginous. That 
the primitive condition of the ischio-pubic bar and of the prepubic process in the 
Amphibia and the early Reptilia was cartilaginous we can not doubt. That these 
should be ossified in the Amphichelydia is remarkable. It suggests that the carti- 
laginous condition in so many hving tortoises may be due to degeneration. 

The limbs of most swamp-loving turtles present primitive conditions of the 
reptilian hmb, both with respect to their composition and their disposition. The 
segments of the Hmbs are mostly flext in one plane, and this plane stands more or 
less at right angles with the axis of the body. The apex of the angle at the elbow 
is directed forward, rather than backward as in the mammals, and the ulna and the 
radius do not cross. There have occurred few unions of bones and these are con- 
fined to the carpus and the tarsus. No bones have suffered important reductions 
or modifications. In the hmbs of swamp-inhabiting turtles there have been few 
changes since Jurassic times; and, since the Amphichelydia, the Cryptodira, and 
the Pleurodira possess similar limbs, it is evident that the primitive turtles possest 
limbs not greatly different. 

From this simple type of limb there has been divergence in two directions; one 
to adapt the animal for life on the land, the other for habitual hfe in the water. 
The highest expression of the former adaptation is perhaps to be found in the limbs 
of species of Testudo. In these the principal modification in the proximal bones 
of the limbs is the drawing downward and toward each other of the tuberosities of 
the humerus. Most important is the shortening suffered by the bones of the digits 
and the reduction of the number of phalanges in each to no more than two. The 
fifth hinder digit may become vestigial. The result of these changes is the pro- 
duction of a short foot resembling that of an elephant and adapted for travel over 
rough and hard ground. 

To fit the animal for habitual life in the water the anterior limb tends to be 
converted into a flipper. First of all, the fingers become elongated to support a 
broad web. Usually the number of phalanges remains unaffected. In the Trio- 
nychidae some of the digits are much elongated and the phalanges are more numerous 
than the normal, and two of the claws have disappeared. In the sea-turtles. 



22 FOSSIL TURTLES OF NORTH AMERICA. 

never coming on land except to deposit their eggs, the fore Hmbs have become 
transformed into definite flippers with the fingers elongated and all bound together 
in a common mass of skin and muscles. Only one or two claws remain. The 
phalanges and carpals are considerably flattened, as is also the humerus. The 
latter also becomes straighter and the insertions of the deltoid muscle descend on 
the shaft. While these changes progrest the hinder limb became relatively smaller 
and fitted for steering the animal. The extreme of these modifications is to be 
seen in the limbs of the leatherback, Dermochelys. Between the short club-like 
foot of Testudo and the long and powerful flipper of Chelonia and Dermochelys there 
is a vast interval. 

Amid all the changes that have occurred in the turtles certain fundamental 
structures have remained unafi^ected. The jaws have always retained their horny 
covering. The quadrate has remained fixt. The cervical vertebra; have kept 
unchanged their number, 8, and the dorsals their original number, lo. All four 
of the limbs have persisted and all the segments of each. 

A consideration of the changes which turtles have undergone and a comparison 
of these with the modifications suffered by other groups of reptiles lead to the 
conclusion that no other order of these animals, except the Squamata, can display 
such a variety of structures. The Squamata, embracing the mosasaurs, the lizards, 
the chameleons, and snakes, have undoubtedly, in adaptation to different modes 
of life, diverged in more directions and gone farther than have the turtles. The skull 
has become modified in more ways; the vertebrae, at least as regards the number in 
the column, have varied more; the limbs have undergone more varied adaptations 
for walking, for climbing, for grasping, for swimming, for leaping; and in the whole 
group of snakes and in many lizards the limbs have wholly disappeared. To these 
denizens of the earth, swarming since probably the Triassic, the turtles must yield in 
variety of form and structure and habits, but probably to no other order of reptiles. 



PRIMARY AND SECONDARY CHARACTERS. 27, 

ON THE PRIMARY AND THE SECONDARY CHARACTERS OF TURTLES. 

It may be interesting and productive of some useful result to endeavor to separate 
the osteological characters that belonged to the most primitive turtles from those 
that may be called the secondary characters, those that have been acquired in later 
times through the exaggerated development or reduction or the suppression of cer- 
tain parts ol the skeleton or their modification of form and connections, in order to 
adapt them to new uses. We will, as heretofore, consider first the shell of the turtles. 

As already stated, the writer holds the view that the earliest turtles possest 
practically two kinds of shell, one purely dermal, consisting of probably a mosaic 
of small bones arranged in at least 12 longitudinal zones. Each zone probably 
consisted of a row of larger bones, bordered on each side by smaller ones. It is not 
necessary to suppose that the spaces between the zones were wholly occupied by 
these smaller bones. Each of these bones was covered by a horny scute. The 
nearest approach to such a dermal shell is in our days seen in Dermochelys, as has 
already been stated. 

Beneath the skin there seems to have existed a carapace more or less complete 
which consisted of a nuchal, a median row of neurals, 8 pairs of costals, a pygal, 
probably one or more suprapygals, and about ii peripherals on each side. To 
what extent the neurals and the costal plates had become anchylosed to the neural 
spines and the ribs respectively it is now impossible to determine. Nor can we say 
to what extent the various elements of this carapace had become connected with one 
another. The existence of the dermal carapace would appear to indicate that the 
subdermal box was not yet closed.* 

There was a subdermal plastron that was composed of at least 11 bones. 
Portis has described Polysternon, which had an additional pair of bones between the 
hypoplastra and the xiphiplastra, making 13 all together. Between these various 
bones there may have existed more or less extensive fontanels. 

According to the author's views, as time went on the external, mosaic-like shell 
disappeared in most turtles, while a more efficient armor was developt out of the 
subdermal elements. In the ancestors of Dermochelys, however, the dermal armor 
was retained, while the more deeply seated one disappeared, with the exception of 
the nuchal bone. 

It is proper to state that all authors do not hold that Dermochelys has descended 
to us in a direct line distinct from other sea-turtles, but has been derived from them 
at a more recent date. On this subject the reader must consult the papers of Baur, 
Boulenger, Case, DoUo, E. Fraas, Hay, Van Bemmelen, and Wieland. 

Most Thecophore turtles have lost the bones of the outer dermal shell. There 
are yet traces of it perhaps in the dorsal and ventral keels of various turtles, in the 
tubercles that diversify these keels, and especially in the rows of horny scutes that 
had their origin from these dermal bones. In one turtle, however, Toxochelys, 
of the Upper Cretaceous, there are yet remains of the dermal armor in the shape of 
a row of bones along the dorsal median keel. For a description and illustrations of 
these the reader must consult later pages of this work. 

In a paper written in 1898 (Amer. Naturalist, xxxii, p. 929) the writer denomi- 
nated such bones as the nuchal, the peripherals, and suprapygals as "fascia bones." 
This was done simply to distinguish them from more superficial bones, called 
dermal. In a recent paper Mr. H. H. Newman (Biol. Bull, x, p. 74) has referred 
to this paper and has insisted that the nuchal is a dermal bone. Such it doubtless 

*For Dr. George Baur's latest views regarding the primitive condition of the carapace and plastron 
of the turtles see Anatomischer Anzeiger, xn, 1906, p. 567. 



24 FOSSIL TURTLES OF NORTH AMERICA. 

originally was, but it is now overlain by the dermal mosaic. Mr. Newman holds also 
that the peripherals and the suprapygals are dermal bones, not what the writer called 
fascia bones or subdermal bones. If the reader will consult the succeeding pages that 
deal with Toxochelys he will see that one of the dermal nodules overhes the second 
suprapygal. 1 he latter is therefore not equivalent to the row of nodules in front 
of It and to those on the tail of the snapping-turtle, but is a bone of a deeper layer. 

We may, therefore, for the present regard the characters of the most primitive 
turtles as having been the following: There was a superficial armor composed of 
dermal bones arranged in at least 7 zones above and at least 5 zones below, with 
many bones in each zone, and each bone covered by a horny scute. Beneath this 
was a subdermal armor. On the upper side of the body, this consisted of the nuchal, 
a row of neurals, 8 pairs of costal plates, suprapygals, and peripherals; below, of 
the entoplastron and at least 5 pairs of subdermal bones. There were 18 presacral 
vertebrae, of which 10 belonged to the trunk and were without transverse processes 
and more or less immovably joined to each other and to the ribs and neural plates. 
The neck was short and consisted of 8 biconcave vertebrae, which possest transverse 
processes and low neural spines. There may possibly have been present some 
cervical ribs. There were 2 sacrals. The tail consisted of biconcave vertebrae, 
each provided with free ribs, with chevron bones below, and perhaps with one or 
more rows of bony nodules above. 

The skull had a complete temporal roof, but the temporal fossa was probably 
not widely open behind. There were nasals, lacrimals, and prefrontals, all 
distinct from one another. There was no parietal foramen. A vomer was present 
but no prevomers. The choanae opened far forward in the roof of the mouth. The 
quadrate was fixt, somewhat excavated to form a tympanic cavity and notcht 
behind for the stapes. Probably the palate was closed by the union of the pterygoids 
with each other and with the basisphenoid. The parietals may or may not have 
sent down each a plate to the pterygoid, in front of the exit of the trigeminal nerve. 
The paroccipitals were free from the exoccipitals. The jaws were without teeth and 
were covered by a sheath of horn. Each ramus of the lower jaw was doubtless com- 
posed of 7 elements, and the dentaries were probably not co-ossified at symphysis. The 
outer surface of the bones of the skull was covered by horny scutes. The shoulder- 
girdle consisted of a pairof coracoids, a pair of scapulae, and a pair of procoracoids; 
the latter probably co-ossifying somewhat late in Hfe with the scapula. Limbs, fore 
and hinder, probably not greatly different from those of living Chelydridae, but more 
crudely modeled. The phalangeal formula was 2, 3, 3, 3, 3 in all the feet. 

If the views exprest above regarding the original composition of the armor of 
turtles is correct, the possession of a carapace consisting exclusively of a mosaic 
of dermal plates, as in Dermochelys, is a secondary character; as is likewise the 
possession of a shell constituted only of the deeper elements, as in the great majority 
of turtles. Other secondary characters are the absence of entoplastron {Dermo- 
chelys, Kinosternon), the absence of peripherals {Trionychoidea), and the absence of 
mesoplastra, as in most Hving turtles. Such too is the lack of nasals and lacri- 
mals in the great majority of turtles. The adaptation of the hmbs for habitual 
swimming is, of course, a secondary modification of these organs. 

In this category, too, belong those modifications of the cervical vertebrae by 
virtue of which the neck has become so greatly elongated in most forms and made 
most freely flexible in a horizontal plane in the Pleurodira and in a perpendicular 
plane in all the others. Most extraordinary of all the secondary characters is that 
complex of modifications which permits the head and neck to be retracted between 
the scapulae, the loop in the neck sometimes reaching backward quite to the pelvis. 



CLASSIFICATION. 25 

THE CLASSIFICATION OF THE TURTLES. 

It is not the purpose of the writer to give here an account of the various schemes 
of classification that have been proposed by writers on the turtles. For such an 
account the reader may consult the third part of the sixth volume of Bronn's 
Klassen und Ordnungen des Thierreichs, beginning with page 347. The following 
is the arrangement ot suborders, superfamihes, and families accepted by the writer. 

All of these families, except those in itahcs, have fossil representatives. 

Order Testudines. 
Suborder I. Athecae. 

Family. Dermochelyidae. 
Suborder II. Thecophora. 

SuPERFAMiLY I. Amphichelydia. 

Families. Pleurosternidae, Baenidse, Plesiochelyidae ? 
SupERFAMiLY 2. Pleurodira. 

Families. Bothremyidae, Pelomedusidae, Chelyidae, Miolanidse. 
Superfamily 3. Cryptodira. 

Families. Thalassemydidae, Toxochelyidas, Desmatochelyidas, Protostegidae, Cheloniids, 
Tretosternidae, Chelydridae, DermatemydidaE, Platysternida, Kinosternidie 
Carettochelydae, Emydidae, Testudinidae. 
Superfamily 4. Trionychoidea. 
Families. Plastomenidae, Trionychidae. 

The arrangement and names of the suborders and superfamihes above given 
are the same as those used by Mr. George A. Boulenger in his Catalogue of the 
Chelonia of the British Museum, 1889. Mr. Richard Lydekker employs practically 
the same groups in his Catalogue of the Fossil Reptilia of the British Museum, 
part III, 1889; but to some of his groups are given different names. Dr. Louis 
DoUo, of Brussels, also divides the turtles into the two suborders Athecae and 
Thecophora. Altho this eminent writer beheves that Dermochelys, the only Hving 
representative of the Athecae, was derived from the Cheloniidae, he separates it as 
the representative of a distinct suborder on account of its extreme modifications of 
structure. It was Cope who first proposed to make this turtle the type of a distinct 
suborder. 

In his Bibliography and Catalogue of the Fossil Vertebrata of North America, 
1902, the present writer assigned to the Trionychoidea, under the name Trionychia, 
the rank of a suborder. A further consideration of the subject has convinct him 
that these turtles should rank lower than a suborder; not higher than a super- 
family. Indeed, they appear to have brancht ofi^ from the earliest Cryptodira; 
but their hneage is so ancient, and they have undergone so many modifications of 
structure, that they are of equal rank with the Cryptodira. The skull is more like 
that of the Cryptodires than that of the Pleurodires, but has developt pecuharities 
of its own. Like the Cryptodires, the temporal roof has never been eaten away from 
below, and always a zygomatic arch remains. The neck is wholly cryptodiran in 
its modifications and is retracted within the shell in the same way. This is a feature 
unique among animals, and it seems improbable that it could be hit upon independ- 
ently by two distinct groups of turtles. The pelvis in its parts and its relationships 
to the shell is entirely cryptodiran. 

Ernst Haeckel, in his Systematische Phylogenie der Wirbelthiere, 1895, page 326, 
has taken the position that the Trionychoidea had probably arisen already in the 
Triassic and that they are to be lookt upon as the group from which all the The- 
cophora have been derived. That the group was establisht even in the Trias is 
possible; that it gave origin to the other groups of Thecophora seems quite impos- 



26 FOSSII- TURTLES OF NORTH AMERICA. 

sible. None of the superfamily has nasals, lacrimals, or temporal roofing. Their 
derivatives must have acquired these bones. The neck is most completely of all 
turtles adapted for retracting the head within the shell. To give origin to the neck 
of the Pleurodires this neck must have lost its peculiar mechanisms and acquired 
those of the side-neckt or snake-neckt turtles. To have produced the neck found 
in the Amphichelydia, that of the Trionychoidea must have shortened greatly 
and have changed its biconvex and its concavo-convex vertebrae into biconcave 
ones. The Amphichelydia, the Cryptodira, and the Pleurodira must have developt 
peripheral bones, instead of inheriting them from their ancestors. The Amphiche- 
lydia and many Pleurodires did not inherit their mesoplastral bones, but acquired 
them independently. The limbs of those Thecophora that are fitted for walking 
must, according to the scheme of derivation proposed by Haeckel, have been evolved 
from feet fitted for swimming. Turtles endowed with a covering of horny scutes 
came from a race which are wholly devoid of these coverings. All these procedures 
are the exact reverse of what is generally beUeved to be the course followed by animals 
in their evolution. If it be claimed that the Trionychoidea of that early time possest 
nasals, lachrymals, and a temporal roof, that the neck was yet short and composed 
of bicoelous vertebrae, that they had peripheral bones and mesoplastra, then they 
were not Trionychoidea at all, but Amphichelydia or something very close to them. 

It is a difficult matter to estimate properly the relative rank of the three super- 
famihes of the Thecophora — the Pleurodira, the Cryptodira, and the Trionychoidea. 
As to the Amphichelydia, there can be no doubt that this group ranks below all 
the others and that from it have been derived all the others. It appears that the 
Pleurodira are usually regarded as the most speciaHzed turtles. There is no doubt 
that the skull and the pelvis have departed farther from those of the Amphichelydia 
than have those of either the Cryptodira or the Trionychoidea. The most im- 
portant modification in the skull is the posterior shortening of the pterygoids, 
whereby the basisphenoid is permitted to join the quadrate. Likewise the outer 
anterior border of the pterygoids has become rolled up in a peculiar manner. On 
the other hand, the skull of a number of genera has retained the nasals and the 
posterior notch in the quadrate, both primitive features. It seems to the writer that 
the neck is less specialized than that of the Cryptodira and Trionychoidea. The 
shell has undergone far less specialization than that of the other groups mentioned, 
many of the genera retaining the mesoplastra, elements unknown in the others. 
On the whole, the writer is incHned to place the Pleurodira below both the Crypto- 
dira and the Trionychoidea. 

As regards the Trionychoidea, it is believed that the skull has departed further 
from the amphichelydian pattern than has that of most of the Cryptodira. This is 
seen in the universal reduction of the temporal roof to narrow postorbital and 
zygomatic arches, the backward prolongation of the squamosal processes, and the 
closure of the stapedial notch in the quadrate. Altho the articular ends of the cer- 
vicals present, so far as is known, less variety of form than in the Cryptodira, the 
neck is, as has been said by Boulenger, more perfectly adapted for complete and 
rapid retraction than in any other chelonian. The carapace has become greatly 
specialized through degeneration of the peripherals and of the horny scutes. The 
Umbs have become moderately specialized for swimming. The Trionychoidea can 
hardly rank below the Cryptodira; it is convenient to let them, in a scheme of 
classification, follow the group just mentioned. 

In fig. 8 an attempt has been made to indicate the connections between the 
different famihes of turtles. This chart differs in some respects from the one pub- 
hsht by the present writer in the Bulletin of the American Museum of Natural 



CLASSIFICATION. 



27 



Recent 


6 






















Pleisto- 
cene 






:S 














'^ 




Pliocene 






g 


1 

ft 






s 


W 




e 



s 




Miocene 




1 

1 
S 






Si 






1 
g 


•5 


*s 




Oligo- 
cene 




\ 














idae 
dac 
ielyidae 






Eocene 


y 
















- 


3" 

i - 

■J 




I 

J 


1 










U.Creta- 
ceoiis 


2 

1 




c 


1 
§ 1 






,,'- 












■3 

e 










L.Creta- 
ceous 




B 


- K| 
i 


c 


i 


1 


'" 


\ 
\ 
N 


[ [ 

1 1 ^ 
\ ] ' / 

\ 1 / 


1 




i 






Jurassic 












\ 

^ 

— • — _ V 




M 


1 










Triassic 




^A.. '^, 


Amphichelydia . ^.„„( 
PrimitiyeCiyPl 


jdira 1 


___ J 




-^ 


e Atheo<l''— 


Pernnian 


Primitive Tliecuphora -~^ ~ " 


r"'"" 


rr-'^--- 









































Fig. 8. — Phylogenetic chart showing supposed relationships of the families 
and higher groups of turtles. 



28 FOSSIL TURTLES OF NORTH AMERICA. 

History, volume xxi, 1905, page 167. Since the publication of that paper discovery 
of new materials has shown that Anosteira belongs among the Dermatemydidae. 
The family Bothremydids, recognized in the present work, is represented in the 
chart as springing from ancestral Pelomedusidae during the Lower Cretaceous. 
It is wholly possible that Taphrosphys itself belongs to the PelomedusidcX, instead 
of the Bothremydida;. It has been concluded that the stock that gave origin to the 
Emydids, and the Testudinidae ought to be brought into closer connection with the 
Dermatemydids. The Carettochelyidae also are represented as arising from the 
Dermatemydidae. It is not improbable that they should have been regarded as 
direct descendants of the Tretosternidae. 

The geological distribution of the families will be considered on a coming page. 

THE DERIVATION OF THE ORDER OF TURTLES. 

At the present day the most interesting and the most difficult questions that 
confront the student of any group of animals or plants are : From what lower group 
was this derived .? and: What are its relationships to kindred groups .? We must 
here at least make the inquiry: From what lower order of reptiles have the turtles 
been derived ? and the further inquiry: What are the relationships of this order to 
other orders of reptiles .? The reply must be: We can not yet give definite answers 
to these questions. 

Nevertheless, some progress appears to have been made toward framing answers 
to these inquiries. It is quite generally agreed that the Cotylosauria or closely 
related forms, known from remains occurring in Permian deposits, are the lowest, 
the least differentiated, of all reptiles hitherto discovered, having themselves been 
derived directly from the StegocephaHa. On this point see Baur (Anat. Anzeiger, 
XII, 1896), Cope (Proc. Amer. Philos. Soc, xxx, 1892, p. 279), Osborn (Mem. 
Amer. Mus. Nat. Hist., viii, 1903, p. 456), Woodward (Vert. Palaeontology, 1898, 
p. 144), Broile (Palaeontographica, li, 1904, p. 106). From the Cotylosauria, Baur 
derived the turtles thru rhynchocephalian ancestors, animals not distantly related 
to Sphenodon. Cope concluded (Proc. Amer. Philos. Soc, xxxv, 1896, p. 124) 
that the cotylosaurian Otocoelidae, which he afterward removed to the order Chely- 
dosauria (Syllabus of Lectures, 1898, pp. 54, 61), were the source of the turtles. 
Osborn, as cited (p. 465), brings the hne of descent of the turtles from the Coty- 
losauria through the Anomodontia. Woodward, as cited (p. 170), calls attention to 
the apparent relationships between the turtles and the Anomodontia, in which group 
he includes the Cotylosauria and the Chelydosauria. Case has publisht a paper 
(Jour. Geology, xiil, 1905, p. 126) in which he describes a species of Diadectes. 
In this communication he shows that the family of Diadectidae is to be transferred 
to the Chelydosauria; and he demonstrates that there are many resemblances 
between the skull of his specimens and that of turtles. He holds that we have in the 
Diadectidae "forms veryclosely related to the ancestral stem of the turtles, which tell us 
much regarding the development of the Testudinata directly from the Cotylosauria." 

The Cotylosauria and the closely related Chelydosauria indicate their eligibility 
to stand as the ancestors of the turtles by the possession of a complete roof over the 
temporal fossa, by the character, rare among reptiles, of having 18* presacral 
vertebrae, by the existence of digits having the phalangeal formula, 2, 3, 3, 3, 3. 
Case has shown that the claims of the Diadectidae for the honor of the ancestry of 
the turtles are superior to those of the Cotylosauria, as limited by him, inasmuch as 

*Broili states that in Lahidosaurus hamatus there are at least 24 presacral vertebrae. 



DERIVATION OF ORDER. 29 

in Diadectes the temporal roof is notcht where applied to the quadrate and the latter 
is excavated to form a tympanic cavity; instead of a pair of prevomers, there is a 
single vomer; and there is a sort of carapace composed of bony plates overlying 
several pairs of the ribs. 

It seems evident that we are getting close to the base of the phylogenetic tree of 
the chelonians; but, Hkewise, that we have not yet reacht it. Taking into con- 
sideration the fact that no turtle possesses a temporal fenestra, that when the 
temporal roof is deficient either the zygomatic arch or the parietal arch or both are 
missing, it seems impossible to derive the turtles from any group of reptiles in which 
even the beginning of such fenestrae has been made. If this view is correct, there are 
excluded at once from the chelonian ancestry all those reptiles belonging to Professor 
Osborn's Diapsida and all the Anomodontia, limited so as not to include the 
Cotylosauria. The Diadectidae, too, would be excluded, if they really possest 
temporal fenestrae. If the presence of a pair of prevomers, instead of a vomer, has 
the importance attributed to it by some recent authors, the Cotylosauria, as hmited 
by Case, would have to forego their claims. Of known reptiles we appear to be 
Hmited to the Diadectidas and the OtocoeHdae, in our search for the ancestors 
of the chelonians. 

It is improbable that any of the reptiles of the Permian of Texas or equivalent 
deposits were the ancestors of the turtles. When we consider that already in the 
Upper Trias the turtle Proganochelys possest a typical shell, we must conclude that 
the earliest of the race must have been in existence as early as the Permian itself. 
It is, of course, possible, indeed quite probable, that some earlier, less differentiated 
form of one or the other of the two famiUes just mentioned gave origin to the most 
primitive turtles. 

It is a serious objection to any of the Cotylosauria, using the name in the wider 
sense, that have been mentioned as possible ancestors of the turtles, that they appear 
to have possest no ventral armor. Almost certainly the turtles inherited this portion 
of the shell, in some form, from the Stegocephalia. The Diadectes described by 
Case presented no traces of a plastron, or of abdominal ribs. There are various 
other reasons why this reptile can not pose as the founder of the chelonian line. 
Among these are the elevated spines of the vertebrae, the great amount of motion 
between the several dorsal vertebrae, their complex structure, the anchylosis of the 
sacrals, and the fact that the plates of the carapace lie between the scapula and the 
ribs. In turtles the scapula lies inside, not outside, of the costal plates. 

Dr. O. Jaekel, of Berlin, has described (Neues Jahrb. Min., i, 1902, p. 127) an 
interesting genus named by him Placochelys and regarded by him as standing in 
ancestral relations to the turtles. The body of the animal is short and broad, and is 
covered by an armor of thick small plates, all closely joined. There is no ventral 
armor. The specimen was found in the lower portion of the Keuper. The well- 
preserved skull shows that there were large supratemporal fenestrae and that the 
nasal openings were separate and far behind the end of the snout. These structures, 
especially the first named, make it improbable that this reptile is at all closely 
related to the turtles. 

The discovery of Otoccelus and Diadectes and Placochelys is like the capture of 
so many stragglers and deserters from an army of heterogeneous composition. 
From these prisoners we may learn something of the personnel and the equipment 
of that army; but it would be unsafe to draw from the data obtained too wide 
conclusions. From Placochelys we learn that in Triassic times there were broad and 
short bodied reptiles of tortoise-like form and covered with an armor of small plates. 
From Diadectes and Otoccelus we discover that in Permian times there were more 



30 FOSSIL TURTLES OF NORTH AMERICA. 

elongated reptiles, in the skulls of which there were many chelonian characteristics 
and whose bodies were protected by an armor of elongated plates overlying the ribs. 
The stegocephalian genus Archegosaurus, of the Permian, possest a ventral armor 
of elongated plates. We may confidently expect that in the Permian there will yet 
be found an animal possessing such a combination of these characters, together 
with other features, that we can recognize in it the ancestor of the order of turtles. 

As to the relationships of the turtles to the orders of reptiles, other than the 
Cotylosauria, only a few words can be said. The opinion is generally maintained 
that their relationships are closer to the Plesiosauria than to any other order. Baur 
(Jour. Morphology, i, 1887, p. 98) has enumerated a number of resemblances 
between the two groups. Among other things, he states that the pelvic arch of the 
Nothosauridae, among the most primitive of the Plesiosauria, is only comparable 
with that of the Testudinata. It may be remarked that the pubes in both the turtles 
and the plesiosaurs are greatly expanded forward and laterally. The ischia are not 
so much alike, those of the plesiosaurs being much more extended backward than 
those of the turtles. Baur says that in the humerus of the lower Plesiosauria there 
is an ectepicondylar foramen; but, according to Fiirbringer, there is only an 
entepicondylar foramen. Baur does not compare the skulls of the two orders. The 
strongest argument in favor of the relationships of the two orders is found in sup- 
posed resemblances in the shoulder-girdles. Probably the best presentation of this 
is to be found in Fiirbringer's elaborate paper in the Jenaische Zeitschrift, xxxiv, 
1900, page 326. In that treatise the author takes the ground that the process 
directed interiorly and inwardly from the scapula in the turtles is a procoracoid, a 
view adopted by the present writer. Fiirbringer also holds that the procoracoid 
was present in the Plesiosauria. This opinion has been accepted by some authors 
and disputed by others. To the present writer the tract of bone in question appears 
to be simply an extension forward and mesially of the scapula, whether that 
extension is regarded as an acromion or a "ventral ramus" of the scapula. The 
tract advanct gradually from the scapula to the midline, and there is no evidence 
that it ever was a distinct bone. The fact that the two clavicles do not lie between 
the ends of these processes does not appear to be decisive, for in numerous reptiles 
the clavicles extend laterally on the scapulae. Opposed to the idea that there are any 
special relationships between the turtles and the plesiosaurs are the facts that the 
latter always possess large supratemporal fenestrae, the former never; and that the 
most primitive plesiosaur, Lariosaurus, has the digital formula belonging to the 
Diapsida and not that of the Synapsida. 

At best, the relationship between the turtles and the plesiosaurs is not close; 
and the most that we can say is that possibly the cotylosaurian stocks of the two 
orders were a little closer to each other than to stocks that gave rise to the other orders. 

THE GEOGRAPHICAL DISTRIBUTION OF LIVING TURTLES. 

At the present day turtles exist in all the larger divisions of the earth, wherever 
there is sufficient heat, at least a moderate amount of moisture, and a supply of food. 
They occupy too all the warmer seas. Fig. 9 is an outline map that includes all the 
lands and seas in which these reptiles are found. The areas occupied by the land and 
fresh-water forms are indicated by parallel rulings, except that certain small islands 
are made black ; but no attempt has been made to show the distribution of the marine 
species. Their realm may be taken as comprising all the seas between the ruled areas. 
This map and those succeeding it have been compiled with considerable care; but 
it is not possible in all cases to determine exactly the limits of the groups. 



GEOGRAPHICAL DISTRIBUTION. 



31 



A glance at fig. 9 will show at once the great influence of heat and cold and the 
lack of moisture. In western Europe, warmed by the sea, the turtles are represented 
by a species which ranges nearly as far north as St. Petersburg; while in Central 
Asia none is known to occur north of Turkestan and the Himalaya Mountains. 
The southern portion of Arabia and the greater portion of the Sahara Desert are 
without turtles, on account of the dryness of the climate. In North America the 
high and cold range of the Rocky Mountains supports no chelonian life. On account 
of its dryness, the western coast of South America has no turtles; and the southern 
extremity of the continent none, on account of its coldness. So much can we say 
with regard to turtles in general; but when we come to study the difi^erent groups 
we shall find that they are often absent from regions where the conditions appear 
to be wholly favorable for their existence. 




Fig. 9. — Map showing geographical distribution of living turtles, excepting those strictly marine. 
Occupied areas ruled with parallel lines, except some small islands, which are in solid black. 

Fig. 10 is intended to display the distribution of the Cryptodira. It is seen to 
differ from the previous map principally in that it shows that AustraHa possesses no 
representatives of the superfamily. 




Fig. 10. — Map showing geographical distribution of the Cryptodira. 

The absence of Cryptodira from Australia is evidence that that region has for 
many geological ages been cut off from the regions to the north of it. It appears 
certain that had the turtles of this superfamily once gained access to this region they 
would have flourisht there. In numbers the Cryptodira exceed today all other 



3« 



FOSSIL TURTLES OF NORTH AMERICA. 



groups of turtles combined. Accepting the genera and species as described by Mr. 
George A. Boulenger in his Catalogue of the Chelonians, there are 30 genera of 
Cryptodira with 140 species; 21 genera of Pleurodira, with 24 species; 6 genera of 
Trionychidae,with 24 species. The headquarters of the superfamilyisNorth America. 




Fig. II. — Map showing geographical distribution of the Chelydridae. Portions of the western 
hemisphere and the island of New Guinea. 

Fig. 1 1 shows the distribution of the Chelydridae. The northern limits of the 
family are somewhat uncertain. The same species, Chelydra serpentina, that occurs 
in Canada, is found also in Ecuador, South America. Until recently it has been 
supposed that the members of this family are confined to the New World; but J. 
Douglas Ogilby has reported (Proc. Roy. Soc, Queensland, xix, 1905, p. 11) the 
discovery of a new genus and species, Devisia mythodes, in the Fly river. New 
Guinea, the river that has furnisht likewise the remarkable turtle Carettochelys. 
The New Guinea snapper has a length of 860 mm., the carapace being 330 mm. 
long. This distribution of the snappers is even more remarkable than that of the 
camels and tapirs. 




Fig. 12. — Map showing distribution of the Dermatemydidae. 

Fig. 12 displays the distribution of the Dermatemydidae. This is one of the 
decadent families of the order, for it abounded in genera and species in the Upper 
Cretaceous of North America and still existed in reduced numbers during the Ter- 
tiary. The family, now consisting of three genera and four species, is confined to 
portions of Mexico and Central America. 

As seen from fig. 13, the Emydidae have a wide distribution, occupying all the 
habitable portions of North America, South America, Europe, Asia, and most of the 



GEOGRAPHICAL DISTRIUUTION. 



33 



P'.ast Indian islands. They are wholly missing from Australia and are conspicuously 
restricted in Africa. Only 2 species occur in the latter continent, and it is possible 
that one of these was introduced by man, since it inhabits also the south of Europe. 
Additional remarks on the distribution of the family will be found under the head 
of Emydida^, on a subsequent page. Unless the genus Gyremys belongs really to 
the Emydidae, the known members of the family appeared at about the same time 




KiG. i^. — Map showing geographical distribution of the Emydidae. 

in America and Europe, in the Lower Eocene. It is remarkable that no members of 
the group were able to find their way into Africa with the Testudinidae, for the latter 
were estabhsht there by the time of the Upper Eocene. 

The Emydidae that occur in South America are all, without doubt, descendants 
of those that entered that continent at a rather late period from North America. 
This was probably during the Pliocene. Only 4 species are known. Of these i 
belongs to Trachemys, represented by several species in North America, and 3 to 
Ntcorta, a genus occurring also in eastern and southern Asia. Nicoria, however. 




Fig. 14. — Map showing geographical distribution of the Testudinid*. 

does not appear to be greatly different from Echmatemys of the Bridget beds, yet 
distinct; and it is wholly probable that both Asia and South America received their 
stock from our own country. The distribution of these turtles resembles that of the 
tapirs. North America possesses at least 25 species of P^mydidae. 

In fig. 14 we have a map representing the distribution of the Testudinid;e, at 
present, or at least within historic times. It will be observed that North America, 
which during the Tertiary was probably everywhere, except in the coldest parts, 



34 



FOSSIL TURTLES OF NORTH AMERICA. 



inhabited by these land tortoises, presents only two very restricted areas. Tho at 
that time it abounded in representatives of the family, some of them of gigantic size, 
it is now poor in species, there being only 3. Almost the whole of South America 
is occupied by the family, but there are only 3 known species. Europe claims 
2 species; while Asia possesses 7. Africa is the headquarters of the family, at 
least 20 species occurring on that continent. These belong to 3 recognized genera. 
The most remarkable feature of the distribution of the Testudinidae is the occurrence 
of species, some of great size, on islands far away from any large body of land, as the 
Galapagos Islands and islands in the Indian Ocean. For further discussion of this 
subject the reader is referred to the treatment of the family on a succeeding page. 
The geographical distribution of the Pleurodira is represented by fig. 15. It 
will be seen that the species are almost wholly residents of the torrid and the south 
temperate zones. A single species has an outlying colony on the Tropic of Cancer, 
at the head of the Red Sea. The wide distribution of these turtles is not surprising, 
seeing that they are a very ancient group. The earliest species that are known to 
belong to the superfamily are described in the present work and come from the 
Upper Cretaceous of New Jersey and New Mexico. Doubtless the group existed 




Fig. 15. — Map showing the distribution of the Pleurodira. 

during the Lower Cretaceous and probably during the Jurassic. In those early 
days the land masses had connections very different from those now obtaining; 
and these turtles were able to become diffused to regions now widely separated by 
deep seas from the original home of the creatures. It would appear more reasonable 
to suppose that South America had received its original pleurodiran population 
from North America, by the way of some Mesozoic land connection; but it is 
possible that these immigrants reacht that continent from Africa. A considerable 
number of authors, viewing the subject from different positions, have concluded that 
there was, during the Mesozoic era, a land connection between South America and 
Africa, which connection was interrupted about the beginning of the Tertiary. 
The existence of such a bridge would enable us to account for the occurrence of 
some closely related species in Madagascar and South America. These species are 
usually referred to the genus Podocnemis; but Baur regarded the Madagascar 
species as belonging to the closely related genus Erymnochelys. Two species of 
Podocnetms are reported from the Middle Eocene beds of the Fayum, Egypt. 

Inasmuch as Pleurodires once occupied a large part of the north temperate zone, 
it is remarkable that they have not been able to maintain themselves there. The 
first and the last that are known to have lived in North America flourisht during 



GEOGRAPHICAL DISTRIBUTION. 35 

the Upper Cretaceous. In England species existed during the Eocene and a species 
of the same epoch has been described from India as a Hydraspis, a genus now 
existing in South America. It is worthy of note, too, that in North America the 
Pleurodires apparently disappeared long before the Amphichelydia did, the stock 
that gave origin to the Pleurodires. The Amphichelydia continued on into the 
Bridget and the Uinta. 

It will be observed from the map (fig. i6) that the Trionychidae occupy the 
habitable portion of North America east of the Rocky Mountains; Africa south of 
the Sahara Desert; Asia south of the Sayanskii and Yablonoi Mountains and 
between the Persian Gulf and the Caspian Sea; and most of the East Indian islands, 
including New Guinea. Altho the oldest-known representatives of the TrionychidEe 
have been found in the middle of the Upper Cretaceous of North America and ahho 
that continent is still inhabited by at least 6 species, it is Asia that furnishes the 
greatest number of living forms of the family, at least 15 species having been 
described from that region, including the islands appertaining to it. In Africa there 
occur about 6 species, so far as now known. As in the case of the Cryptodires, the 
trionychids have prest southward close to Austraha, without having succeeded in 




Fig. 16. — Map showing the distribution of the Trionychidae. 

reaching it, Pelochelys cantoris having been reported from New Guinea. No Triony- 
chidae have been found in the Tertiary beds of the Fayum, Egypt. Considering 
the fact that true trionychids antedate known pleurodirids, it appears strange that 
the former were not able to reach Austraha with the pleurodirids; more especially 
since the trionychids are, and have been since the Judith River epoch, excellent 
swimmers. A problem fully as hard to solve is the absence of trionychids from the 
continent of South America. So far as we can judge, they might easily, within 
rather recent geological times, have made their way thither from North America. 
Again, Ameghino has described what he regards as a species of Trionyx from the 
Cretaceous of Patagonia. The description is very brief and no figures have been 
furnisht. If representatives of the superfamily had reacht the continent by the 
time of the Upper Cretaceous it is remarkable that they were not able to maintain 
themselves there. No region appears to be better adapted than this for river-loving 
species of turtles. 

In Europe we have another illustration of the fact that animals may be driven 
from a region in which they have once obtained foothold. No species of the 
superfamily now occupies that region; but numerous species did exist there during 
the Eocene, the Oligocene, and the Miocene. It has not yet been determined 
what the influences were that operated against them. 



36 



I'OSSII. lURTI.KS Ol' NORTH AMHRICA. 



THE GEOLOGICAL DISTRIBUTION OF THE TURTLES. 

In tables i and 2 the writer has endeavored to present in as accurate and effective 
a manner as possible the chronological distribution of the fossil turtles of North 
America, with the positions of the turtle-bearing beds and the level at which each 
species has been found. Table i represents the principal divisions and subdivisions 
of the Me.sozoic age, except the Triassic, while table 2 deals in like manner with the 
Cenozoic. No small difficulty is experienct in the preparation of such tables. The 
limits of the larger formations and the periods which they represent have not 
received general acceptance; and when we come to consider the smaller divisions 
and the correlation of deposits in distant regions there are in many cases widely 
divergent views. Again, in the collection of the fossils there has often been too 
little care exercised in preserving records of localities and levels. An interroga- 
tion mark (.?) preceding any generic name indicates that the species immediately 
succeeding possibly does not belong to the level indicated. 

Table i. — Principal divisions of the "Jurassic and Cretaceous, with the species of turtles known from each. 







Denver. 


? Glyptops depressus. 


Arapahoe. 


Adocus ? lineatus, Plastomenus .' punctulatus, P. insignis, Aspideretes vagans. 


Baena marshi 


, B. hatcheri, Eubaena ccphalica, E. latifrons, Thcscelus insil- 






Laramie. 


iens, T. ra] 


iens, rNaiadochelys ingravata, Basilemys sinuosa, Compsemys 








victa, C? obscura, Helopanoplia distincta, Aspideretes fovcatus, A. beech- 






Fox Hills. 


cri, A. austerus, A. fontanus, A.vorai. 


No turtles known. 




Bear Paw. 


No turtles known. 


Eastern Region. 






(Greensand, etc., aporoximatelv 










Baena callosa, B. . equivalent to Pierre, etc.) i 










antit]ua, Boremys 


Bothremys cooki, Taphrosphys sul- 
catus, T. longinuchus, T. leslianus, 










pulchra, Neuranky- 










lus eximia, Chari- 


T. strenuus, T. molops, T. nodo- 










temys captans, 


sus, T. dares, Ainblvpeza entellus, 










Polythorax missuri- 


Osteopygis emarginatus, O. gibbi, 










ensis, Basilemys 


O. robustus, O . chelvdrinus, O.ero- 










variolosa, B. im- i sus, O. borealis, O. platylomus, O. 
hricaria, ?Compse- sopitus, Catapleura repanda, C. 








Judith River. 




Upper 
Cretaceous. 


Pierre. 




mysvicta,Gyremys ponderosa, Peritresius ornatus, 
spectabilis, Plasto- I.ytoloma angusta, L. jeanesi, L. 
menus costatus, wielandi, Erquelinnesia molaria. 










Aspideretes fovea- 


Rhetechelys platyops, .^Neptu- 


Mesozoic. 








tus, A. coalescens, 
A. splendidus, A. 
beecheri. 


nochelys tuberosa, Atlantochelvs 










mortoni, Adocusbcatus, A.puncta- 










tus, A. lacer, A. syntheticus, A. 












agilis, A. pravus, Agomphus turgi- 












diis, A. petrosus, A. tardus, A. 
pectoralis, A. firmus, A. masculi- 


Oagget. 


Toiochelys latire- 










mis ?, Porthochelys 


nus, Zvgoramma striatula, Z. micro- 








Eagle. 


browni, Archelon 


glvpha, Homorophus insuetus, 










ischyros, A. marshi. 


Amyda = prisca, .\J halophila. 






Toxochelys latiremis, T. serrifer, T. brachyrhina, T. steno- 






Niobrara. 




pora, T. elkader, T. procai, T. bauri, Cynocercus incisus, 
Porthochelys laticeps, Protostcga gigas, P. potens, P. 










advena. 


BentoD. 


Glyptops pervicax, Desmatochelys lowi. 


Dakota. 


No turtles known. 


Lower 
Cretaceous. 


Washita. 


Glyptops ? belviderensis. 


Fredericksburg 


. 


No turtles known. 


Trinity. 


Glyptops cselatus (In Potomac beds). 


Jurassic. 


Morrison. 




Glyptops plicatulus, Probai-na sculpta. 


Unkpapa. 


No turtles known. 


Sundance. 


No turtles known. 



GEOLOGICAI, DISTRIBUTION. 37 

Table 2. — Principal divisions of the Cenozoic, with the names of the turtles found m each. 



Ceuozoic. 



Pleisto- 
cene. 



Pliocene. 



Miocene. 



Oligocene. 



Chelydra serpentina, Clen:iniys percrassa, C. insculpta, Chrvsemys timida, Trachemys petrolei, T. 
bisornata, T. trulla, Terrapene marnochi, T. eurypygia, ?T. canaliculata, Testudo laticaudata, T. 
hexagonata, T. atascosae. 



Peace 
Creek. 



Blanco. 



Upper. 



Middle. 



Lower. 



John Day. 



Macroclemysfloridana, Deirochelys fioridana, Trachemys sculpta, T.jarmani, T. euglypha, 
Pseudemys extincta, Terrapene putnami, Testudo crassiscutata, Platypeltis ferox? 



Testudo turgida, T. pertenuis, T. campester, CIcmmys hesperia (Rattlesnake beds). 



Plains and Mountain Region. Yorktown Epoch of Atlantic Region. 

Trachemys hilli, Testudo orthopygia, T. Syllomus crispatus, Procolpochelys gran- 



edec, T. hollandi, T. impensa, T. niobra- 
rensis,T. gilberti, T. undata, T. klettiana. 



daeva, Amyda? buiei, A.? lima. A.? cel- 
lulosa. 



Clemmys saxea, Testudo pansa, T. osborniana^ T. farri. 



Testudo vaga, T. arenivaga, T. peragrans, T. inusitata, T. emiliae. 
Stylemys oregonensis, S. capax, S. conspecta, ?S. calaverensis. 



Brule. 



Styieinys nebrascensis, Testudo thomsoni, T. laticunea, T. ligonia, T. amphithorax, T. 
quadrata, T. cultrata. 



Eocene. 



Chadron. 



Uppe 



Middle. 



Xenochelys formosa, Graptemys inomata, Testudo brontops, T. exornata, Platypeltis 
leucopotamica. 



Uinta. 



Bacna emiliae, Echmatemys callopyge, E. uintensis, Hadrianus tumidus, 
Amyda crassa. 



Bridget. 



Lower. 



D. ?Echmatemys septaria (Washakie), ? Amyda egregia 
(Washakie). 

C. Anosteira ornata, Amyda salebrosa, Platypeltis 
serialis, P. postera. 

B. Baena arenosa, ?B. clara, B. sima, B. riparia,Chis- 
tcrnon undatum, C . hebraicum, Baptemys wyomin- 
gensis, ?B. fluviatilis, Anosteira ornata, Clemmys 
morrisiae, Echmatemys wyoiningensis, E. haydeni, 
E. stevensoniana, ?E. septaria, E. arethusa, E. 
cyane, E. shaughnessiana, E. ocyrrhoe, E. tcgle, 
E naomi, E, pusilla, E. latilabiata, ?E. polycypha, 
?E. terrestris, Hadrianus corsoni, Achilemys 
allabiata, Plastomenus thomasi, P. visendus, P. 
tantilluSj P. ccdemius, P. molopinus, Aspideretes 
guttatus, A. ellipticus, A. grangeri, Amyda uinta- 
ensis, A. scutumantiquum, A. ? concentrica, A. 
franciscae, A.? exquisita, A. mira, A.? tritor, 
Temnotrionyx manducans, Platypeltis serialis, P. 
trionychoides, P. heteroglypta, P. cxtensa. 



Gulf Region. 
Jackson epoch. 



Hadrianus schucherti 



A. Anosteira radulina, Hybemys arenaria, Amyda £equa. 



Wind 
River. 



Baptemys tricarinata. 



Wasatch. 



Rocky Mot:NTAiN Rf.gion. 
Baena arenosa, Kallistira costilata, Notomorpha gravis, 
Echmatemys lativertebralis, E. ciboUensis, E. me- 
gaulax, E. testudinea, E. euthneta, Hadrianus 
niajusculus, Plastomenus catenatus, P. corrugatus, 
P. communis, P.? Icptomitus, P.? lachrymalis, P. r 
fractus, Amyda cariosa, A. radula, Platypeltis serialis. 



Easttrn Region. 
Lerabonax polerai- 
cus, L. insularis, 
L.propylaeus, Che- 
Ionia parvitecta, 
Agomphus oxyster- 
num, Amyda? pen- 
nata. A.? Virgin- 
ian a . 



Torrejon. 



Puerco. 



Baena escavada, Alamosemys substricta, Hoplochelys saliens, H. paludosa, 
Aspideretes singularis. 



?Hoplochelys crassa, Conchochelys admirabilis, Aspideretes sagatus, A. puer- 
cencis, A.? nassau (Fort Union beds). 



ig FOSSIL TURTLES OF NORTH AMERICA. 

In North America no turtles are known to have existed in deposits below the 
Morrison beds of the Upper Jurassic. Dr. Edward Hitchcock has indeed assigned 
to the tortoises certain tracks observed by him in the Triassic sandstones of Massa- 
chusetts and Connecticut; but, while there is no improbability that turtles occurred 
there and then, there is no certainty of it. As is seen from table i, 2 species of 
turtles, both belonging to the Amphichelydia, have been found in the Morrison beds 
of the Rocky Mountam region. These beds are sometimes regarded as belonging to 
the Lower Cretaceous, equivalent to the Wealden of Europe, but it is more probable 
that they correspond to the Kimeridge Clay or the Purbeck (Fraas, Zeitschr. deutch. 
geol. Gesellsch., liii, 1902, briefl. Mitth., p. 59) or even a Httle lower. So far as now 
known, no other group than the Amphichelydia are represented until we reach the 
Benton, of the Upper Cretaceous. In the lowest division of this there occurs an 
undoubted marine turtle belonging to the Cryptodira. A species of Glyptops is 
found in the Potomac beds near Washington, District of Columbia, and another 
species of probably the same genus in the Washita beds of Kansas. 

Turtle remains are not uncommon in the Niobrara beds of Kansas, but when we 
come to examine the list, we find the species not numerous, and they belong to only 
four genera. The species of Toxochelys and oi Porthochelys appear to have hved in 
the Niobrara ocean near the coasts. The species of Protostega, on the other hand, 
evidently ventured far out on the high seas. Toxochelys and Porthochelys appear to 
have continued on into the Pierre; Protostega was there replaced by, or transformed 
into, the huge Archelon. 

About the middle of the Upper Cretaceous, conditions were favorable for the 
existence and the inhumation of many species of turtles. These are found now in 
two widely removed regions and in deposits made under widely different conditions. 
On the Atlantic border, especially in New Jersey, occurs a series of marine deposits 
from which have been derived about 40 species of turtles, including 9 species 
of Pleurodira and 2 species of Trionychidae. The remainder are Cryptodira, among 
them many coast-inhabiting Thalassemydidae, all of which were probably furnisht 
with jaws fitted for crushing hard mollusks and crustaceans. The family of Dermate- 
mydidae, represented now by only 3 genera and 4 species, appear in great numbers 
and variety, especially in the New Jersey Cretaceous greensand. Whence this 
assemblage of turtles came we have no clue. Scant remains indicate the existence 
of two species of large marine turtles, Atlantochelys and Neptunochelys. 

In the heart of the continent at nearly the same time, possibly a little earlier, 
there were being laid down fresh and brackish water deposits, now known as the 
Judith River beds. They are found in Montana and British America, and have 
furnisht about 15 species of turtles; but these are quite different from those of the 
Atlantic coast deposits just mentioned. There are, indeed, 4 or 5 species of triony- 
chids of the genus Aspideretes, a genus Hving now in Asia, a species of Plastomenus, 
and 3 or 4 species of Dermatemydidae; but the latter belong to genera distinct from 
those found in the New Jersey deposits. In these Judith River beds reappear rep- 
resentatives of the Amphichelydia, turtles which we have found to characterize the 
Upper Jurassic and the Lower Cretaceous. In America the turtles of this group 
appear generally to have avoided true marine conditions. 

Succeeding the Pierre and the Fox Hills epochs came that of the Laramie. In 
the fresh and brackish water deposits laid down during this time there were buried 
remains of a great variety of turtles, but unfortunately these remains are usually 
very fragmentary; 16 species are recognized as belonging here. Their relationships 
are close to the turtles of the Judith River beds, some species being as yet undis- 
tinguishable. The conditions under which the two deposits were laid down were so 



GEOLOGICAI, DISTRIBUTION. 39 

similar that there is no wonder that the faunae did not differ greatly. In the Laramie, 
as in the Judith River, there were Baenidie and Trionychidae. The Dermate- 
mydidae are represented by at least one species, Bastlemys stnuosa, not greatly 
ditferent from B. variolosa of the Judith River. The Pleurodira appear to be 
represented by one species, Naiadochclys ingravata, from New Mexico. 

On entering the 1 ertiary there is no striking change in the turtle fauna. In the 
Fort Union, the Puerco, and the Torrejon, there are yet Trionychidae, Dermate- 
mydidae, and Baenidae. Representatives of the same famihes pass up into the 
Wasatch. Here, however, new elements enter, the Emydidae and the Testudinidae. 
It is not improbable that Gyremys spectabihs of the Judith River beds is an emyd, 
but the group is unmistakably represented in the Wasatch by Echmatemys, a genus 
in some respects highly specialized. 1 he 1 estudinidae are represented by the 
genus Hadrianus, the oldest-known genus of the family. All these Wasatch turtles 
inhabited either the land or the fresh waters of streams. 

In the Atlantic region we have nearly contemporaneous deposits; and in them 
we find fragmentary remains of a few probably marine turtles and of Trionychidae. 

The Wind River beds have so far furnisht only a single species of Baptemys, and 
the humerus, 187 mm. long, of a trionychid. 

The Bridger beds of Wyoming are exceedingly rich in turtle remains, as they 
are also in the bones of crocodiles and mammals. The Baenidae were numerous in 
species and individuals. Only 2 genera of dermatemyds have been found. Emy- 
didae abounded, and Trionychidae ran riot. In addition to these there were a few 
species of Plastomenidae. All together, there are 50 or more species of turtles 
described from the Bridger Eocene. The abundance of Baenidae and especially 
of the Trionychidae shows that there were numerous streams and lagoons; and this 
conclusion is confirmed by the presence of many species of crocodiles. 1 he occur- 
rence of the great turtle Hadrianus seems to indicate the proximity of dry land. 

Nearly all the species of Bridger turtles occur in the lower portion, that known 
as level B. No turtles have yet been described from the limestone bands, but 
fragmentary remains occur there. These bands appear to have been laid down in 
shallow lakes. 

So far as known the turtles of the Uinta beds belong to genera found in the 
Bridger beds. No Plastomenidae have been found, and the Baenidae appear for the 
last time in our calendar. 

During the Oligocene epoch the scene, for the student of turtles, shifts from the 
sea shore and the mountain regions to the Great Plains. In the lowest division, the 
Chadron or Titanotherium beds, are found i trionychid, i dermatemyd, and 
I emyd, silent witnesses of the presence of streams. On the other hand, there were 
numerous species of Testudinidae, or dry-land tortoises, some of which attained a 
large size. Of Stylemys nebrascensis great numbers of shells have been found in 
South Dakota and Colorado, in the Brule clays, or Oreodon beds. Species of 
Testiido were more abundant in the same deposits in Colorado. There can be no 
doubt that at this time the climate of the Plains region had become arid and the 
streams few. A similar climate appears to have prevailed in the John Day region 
of Oregon, where 2 or 3 species of Stylemys abounded, but, so far as known, no 
other turtles. 

The Miocene deposits of the interior ot the continent are characterized by the 
presence of species of Testiido, many of them of large size, resembling the gigantic 
tortoises of the Galapagos Islands. Sixteen species are described. In the Middle 
Miocene of Oregon there has been found a species of Clemmys (C. saxea); in the 
Upper Miocene of Kansas, Trachemys hillt. In the Yorktown beds of the Atlantic 



40 FOSSIL TURTI.KS OF NORTH AMKRICA. 

Slope are found two species of the Cheloniidae and fragments of three species of 
Trionychidse. We can not doubt that in the streams of the Mississippi Valley and 
eastward there was an abundant population of water-loving turtles, but farther 
westward this order of reptiles was represented principally by the land tortoises. 

During the Pliocene the land tortoises continued to predominate, especially in the 
interior region. Three species are known from the Blanco beds of Texas. In deposits 
of apparently the same age in Oregon there has been found a species of Clenimys. 

In the Peace Creek beds of Florida, belonging apparently to the Upper Pliocene, 
there are found, with one large Testudo, numerous Emydidae and a species of 
Chelydrida?. These are closely related to species yet living in that region. Among 
the numerous turtle bones put in the writer's hands from Hillsborough County, 
Florida, are many fragments that evidently belonged to yet undescribed species of 
Emydidae and Trionychidae. 

In the scattered deposits of the Pleistocene, in which we might expect to find 
remains of turtles, we discover a few species; and these present a still closer approach 
to those now inhabiting the same territory. In what probably corresponds to the 
Equus, or Sheridan, beds of the region west of the Mississippi River have been 
discovered a species of Chrysemys, 3 species of Trachemys, a species of Terrapene, 
and 3 species of Testudo. It is worthy of note that no Testudo attains the size 
that was reacht by species of the genus during the Miocene and the whole of the 
Pliocene. In the Atlantic region, in caves and superficial deposits, have been found 
remains of the snapping-turtle, the sculptured turtle, another supposed species of 
Clemmys, and one or more species of box-tortoises. 

Briefly let us consider the geological history of the turtles of other regions. 

The earHest known turtle remains have been found in the Middle Triassic, the 
Muschelkalk, of Germany. Huene (Palaeont. Abhandl., x, 1906) has described 
a few cervical vertebrse which he regarded as probably having belonged to crypto- 
diran turtles. In the Upper Triassic of the same country, the Keuper, has been 
found Proganochelys, a nearly complete shell of which has been described by E. Fraas 
(Jahresh. Ver. Naturk. Wiirrt., lv, 1899, p. 401 ). The present writer believes that 
this turtle belonged to the Amphichelydia, and it is probable that the cervical 
vertebrae from the Muschelkalk belonged to some turtle of the same group. 

The next oldest known turtle, known only from impressions of the carapace on 
slabs of rock, is Protochelys stncklandi, from the Stonesfield slate, of the Great 
Oolite, of Oxfordshire, England. It belongs probably to the Amphichelydia. 

In contrast to the scanty chelonian population of the North American Upper 
Jurassic, that of Europe was extremely numerous. From the Jurassic at Solothurn, 
Switzerland, about 15 species have been described. From deposits of approxi- 
mately the same age in Germany, France, and England, numerous other species 
-have been reported. Many of the species have come from the Kimeridge, of the 
upper portion of the Great Oolite, a formation found in England, France, and 
Germany, and belonging near the level of the Morrison beds of Wyoming, as 
already stated. The principal genera described from the Upper Jurassic of Europe 
are Pleurosternon, Platychelys, Plesiochelys, Idiochelys, Hydropelta, Parachelys, 
Acichelys, Thalassemys, Stegochelys, and Tropodemys. The first two belong 
without doubt to the Amphichelydia, Pleurosternon being closely related to Glyptops 
and Platychelys to Prohaena. Craspedochelys and Plesiochelys are almost certainly 
not Pleurodira and may be referred provisionally to the Amphichelydia. The 
other genera are to be referred to the Thalassemydidae, a family of Cryptodira. 
Similar turtles are found a little higher up in the European Jurassic, in the Purbeck 



GEOLOGICAI, DlSTRlliUTION. 4I 

and Portlandian; likewise, in the Wealden, of the Lower Cretaceous deposits of 
approximately the age of the Trinity and Potomac. In the Portlandian is found a 
species of Pleurosternon. In the Wealden occurs the genus Tretosternon, which 
may have given origin to the Dermatemydidae. 

In the Gault, at the base of the Upper Cretaceous of England, have been found 
remains of a large turtle which is called by Lydekker Chelone jessoni (Quart. Jour. 
Geol. Soc, XLV, 1889, p. 231). While it is possible that this species belonged to the 
Chelonidae, it is improbable that it was congeneric with our living green-turtle. It 
would be more proper to call it Cimochelys jessoni . 

The Cambridge Greensand, of the Cenomanian, near the time of the American 
Dakota or Benton, furnishes a number of turtles. These are represented by skulls 
alone and are placed m the genus Rhtnochelys. Their affinities are uncertain, but 
they are neither Pleurodira nor Trionychoidea. The genus seems not to be repre- 
sented in America. 

In the Lower Chalk, Turonian, of Kent, England, are found remains which are 
assigned by Lydekker (Cat. Chelonians, 1889, p. 34) to Chelone benstedi. For the 
reason noted above, this species ought to be called Cwiochelys benstedi, as it was 
named by Owen. The Turonian was deposited approximately at the time of our 
Niobrara beds. 

In the Upper Cretaceous of England and the continent is found a huge marine 
turtle, Allopleuron hoffmani; its costals are greatly reduced. In Italy has been 
found another large sea-turtle, Protosphargis, reminding us of Protostega and 
Archelon, of the American Upper Cretaceous. 

In the Upper Cretaceous of Provence, France, has been discovered the remark- 
able turtle, Polysternon. Besides mesoplastra it possesses a pair of bones between 
the hypoplastra and the xiphiplastra, and the pelvic bones are sutured to the xiphi- 
plastra. It is regarded as a pleurodire; and it appeared about the time that this 
group presented itself in America. 

During the Tertiary period the history of European turtles appears to have run 
on much as it did in America, altho in each country the history had its peculiar 
features. Osborn (Ann. N. Y. Acad. Sci., xiii, 1890, p. 7) finds that America and 
Europe had a similar mammalian fauna throughout the Lower Eocene, but that 
there followed a Middle and Upper Eocene interval of faunal separation of the two 
countries; while again there was an approach, from the beginning of the Oligocene 
onward until the late Pleistocene. With respect to the turtles it may be said that 
the two regions were farther apart at the beginning of the Eocene, converged to 
perhaps the middle of the Pliocene, then diverged. 

In the London Clay of England is found Eosphargis, the earliest representative 
of the Athecae. In Belgium at the same time there existed Pseudotrionyx, a relative 
of the living Carettochelys. In England there were yet two species of Pleurodires. 
So far as known, the group was not represented at the time in America. In Europe 
there were no Amphichelydia, no Dermatemydidae, no known species of Plasto- 
menidae, and no Trionychidae. The species of Argillochelys may belong to the 
Cheloniidae. Species referred by Lydekker to Chrysemys represent the Wasatch 
Emydidae, while Homopus comptoni represents Hadrianus. 

The Middle Eocene of Europe witnest a great multiplication in the number of 
Trionychid,-e. Species referred to the yet living Asiatic genus Ocadia, of the 
Emydidae, resembled the Bridger genus Echmatemys. The Bridger epoch differs 
from the European Eocene in its numerous species of Baenidae. 

During the Oligocene, Europe possest numerous Trionychidae. Doubtless in 
America, too, they existed in numbers, but they have mostly escaped preservation. 



42 FOSSIL TURTLES OK NORTH AMERICA. 

America at that time yet harbored Dermatemydidae; while Europe gave asylum to 
Chelydridae and to the pecuHar genus Ptychogaster. 

During the Miocene, land tortoises, Testudinidae, abounded in both America 
and Europe, turtles especially characteristic of dry lands. Europe possest various 
genera of Emydidae and species of Chelydra, a genus now found only in North 
America, but apparently a late immigrant thither. 

There are evidences that during the PHocene the turtle population of Europe 
diminisht in genera, species, and probably in individuals. Trionychidje were still 
found in Italy, but are not known after this time in Europe. 

An interesting region for the student of chelonians is found in India. Here 
numerous species of i rionychidae, Emydidae, and Testudinidae have been exhumed 
from late Tertiary; but most of the forms appear to belong to existing genera. 

From the Upper Eocene fluviomarine beds of the Fayum of Egypt we have 
recently secured a most interesting and instructive addition to our knowledge of 
the turtles of that time, Dr. C. W. Andrews having described 9 species from those 
beds. One of these is a species of Psephophoriis, related to Dermochelys. Of 
Testudo there are 3 species, a shell of one of which had a length of 1500 mm. A 
portion of the skull of a supposed species of Thalassochelys is also described. Of 
Podocnemis there are 2 species. Besides these, a new genus of Pleurodira, Ste- 
reogenys, with remarkable characters, is made known to us. 

We must not omit to mention that remarkable Pleurodiran turtle, Miolania, 
which was originally described from remains found in Pleistocene deposits on 
Lord Howe Island, east of Australia. A second species was afterward discovered 
in Queensland, Austraha; and more recently Dr. A. S. Woodward has described 
a third species from northern Patagonia. Outside the remarkable structure of 
this turtle, it becomes interesting for the reason that its presence in the regions 
named appears to confirm the theory that there was once land connection between 
Australia and South America. 



DESCRIPTION OF GROUPS AND SPECIES. 43 

DESCRIPTION OF GROUPS AND SPECIES. 

Order TESTUDINES Batsch. Turtles and Tortoises. 

Reptiles with the body relatively short and broad. Quadrate bone immovably joined to the 
pterygoid, the prootic, and paroccipital; its outer surface excavated to form a tympanic cavity. 
Paroccipitals not consolidated with the exoccipital. Vomer single, if not missing. Pterygoids 
closing the palate by their inner borders. Teeth never present; the jaws always armed with a 
horny covering. Nasal opening single. Dorsal ribs each with a single head; at least the anterior 
ones intervertebrally attacht. A nuchal bone always present. Cervical vertebrae eight; dorsals 
ten. Epiplastra (clavicles) and at least six other bones present in the abdominal wall. No 
sternum or sternal ribs ever developt. Each half of the pelvis composed of three bones, all con- 
tributing to the acetabulum. Four limbs always present. Humerus with ectepicondylar passage. 

Thi.s order of Reptilia is divided into two suborders, the Athec.^': and the 
Thecophora. 

Suborder ATHECffi Cope. 

Turtles which retain the primitive dermal armor, with at least traces of the suhdermai 
expansions connected with the ribs. 

Of this suborder there is no known representative from North American 
deposits, unless possibly certain dermal bones that have been found to accompany 
the remains of Bastlosaurus (Zeuglodon) belonged to some otherwise unknown 
species of the group. This is improbable, however, as shown by Dames (Pal. 
Abhandl., v, 1894, p. 220). In Europe the suborder is represented by Eosphargis, 
of the London Clay of England, by P.r^/)/!o/?/!or«.f, of the Oligocene and Miocene of 
the Continent, and perhaps by Pseudosphargis, of the Upper Oligocene of Germany. 
The latter genus is based on a very imperfect skull; and, while presenting many 
resemblances to Dermochelys, is not regarded by the present writer as being at all 
certainly a member of the Athecae. This turtle possest descending plates from the 
parietals to the pterygoids. 

Suborder THECOPHORA DoUo. 

Turtles in which the primitive dermal armor has become obsolete or abolisht. Always a 
more or less complete carapace formed by at least the expansions of the ribs, the nuchal bone 
and with rare exceptions a series of neurals; usually a very complete shell formed by the bones 
mentioned, together with series of peripherals and a varying number of plastral bones. Skull 
always furnisht with descending parietal plates. 

This suborder, containing the vast majority of turtles, living and extinct, 
consists of four superfamiHes, the Amphichelydia, the Pi.eurodira, the Crypto- 
DIRA, and the Trionychoidea. Of the first there are no living representatives. 

Key to Superfamilies of Thecophora. 

1. Mesoplastra present or absent. If absent, hinder lobe of plastron with rough scars for union with 

pelvic bones except in Plesiochelyidse. 

a'. Mesoplastra always, so far as known, present; no plastral scars Amphichelydia 

c?. Mesolpastra present or absent; rough scars on hinder lobe of plastron Pleurodira 

2. Mesoplastra always absent; no sutural scars on plastron. 

n'. Peripheral bones always present Cryptodira 



ea 



a . Peripheral bones present only in one gtnus now existing Trionychoidi 

SuperfamUy AMPHICHELYDIA Lydelcker. 

Thecophorous turtles having a carapace composed of neural, costal, and peripheral bones 
and a plastron in which the epiplastra are in contact with the hyoplastra. Mesoplastra usually, 
perhaps always, present. Intergular and inframarginal scutes probably always developt. 



44 KOSSir, TURTI.KS OK NORTH AMERICA. 

Skull essentially crvptodiran in stiuctuie, but with various primitive elements. Neck short, 
the vertebrae little differentiated. Limbs, so far as known, fitted for walking. 

This group was establisht by Mr. Richard Lydekker, to include, as he states, 
a number of generalized late Mesozoic forms which may be regarded as allied to the 
earlier (and then unknown) progenitors of the Pleurodira and Cryptodira. He 
characterized them as having a shell constructed on the plan of that of the Crypto- 
dira and Pleurodira, in which mesoplastral bones and an intergular shield are 
developt. The pubis may articulate, without sutural union, with the xiphiplastron. 
At the time he wrote the skull and neck were not known. The coracoid and the 
humerus were regarded as being ot the pleurodiran type. The genera included 
were Pleurosternou, Baena, and Platychelys. (Lydekker, Cat. Foss. Rept. Brit. 
Mus., pt. Ill, 1889, p. 204.) 

In 1890 (Amer. Naturalist, xxiv, p. 530) and 1891 (Proc. Acad. Nat. Sci. Phila., 
p. 411) Dr. George Baur, working on materials at Yale University, added greatly 
to the knowledge of the group, regarded by him as a suborder. He likewise furnisht 
a definition of the group. Ihe present writer (Bull. Amer. Mus. Nat. Hist., xxi, 
1905, p. 137), having studied well-preserved remains of Baena from the Bridger 
beds, was enabled to make further additions to our knowledge of the Amphichelydia 
and to correct some of Dr. Baur's statements and generalizations. 

In this superfamily the plastron appears to be in all cases more or less closely 
joined to the carapace by sutural union with the peripherals, and in the Baenid:e 
the union is strengthened by powerful axillary and inguinal buttresses. In all 
forms known to belong to the group there are well-developt mesoplastra; but since 
these bones have been abolisht from the plastron of all the Cryptodira and from 
thatof most of the Pleurodira, there seems to be no good reason to suppose that they 
might not have been supprest in the case of some of the Amphichelydia. Accord- 
ingly the writer has ventured (Bull. Amer. Mus. Nat. Hist., xxi, pp. 144, 167) to 
include provisionally in the superfamily the Plesiochelyidae. Nothing is known 
certainly of the members of the family except the shells. 

On the carapace of the Amphichelydia, besides the scutes found in such turtles 
as the F^mydidae, there may occur supernumerary vertebrals, costals, and supra- 
marginals. On the plastron there are, in all known cases, intergulars and full series 
of intramarginals. The boundaries between the scutes are liable to vary in their 
positions. T he sulcus between the paired scutes of the plastron especially is often 
found wandering far from the midline. It is as if the limits of the scutes had not 
m these early forms yet become firmly establisht. In the skull there are such primi- 
tive elements as distinct nasals and lacrimals. The temporal region is always 
covered over and the quadrates are notcht for the passage of the stapedial rod. 
The pterygoids never have the wing-like expansions that characterize the Pleuro- 
dira; and, unHke the latter, the pterygoids push themselves backward between the 
quadrates and the basioccipital and the basisphenoid. 

The cervical vertebrae may, as in Glyptops, be all bicoelous, or, as in the Baenida?, 
one end of most of them may be convex. The neck was short and the differentiation 
of the cervicals had progrest so little that probably these turtles could protect their 
heads neither by withdrawing them within the shells as do the Emydidae, nor by 
laying them on one side beneath the front border of the carapace after the manner 
of the Pleurodira. 

In the Pleurosternidae and the Baenidae, whose limbs are now known, these were 
fitted for progression on land. Doubtless they were inhabitants of the waters of 
lakes and rivers and were good swimmers, but there was no special modification of 
the limbs for swimmine. 



PLEUROSTERNID^. 45 

In addition to the families Pleiirosternida; and Baenidae here treated, and the 
Plesiochelyidae provisionally included, the writer refers to this superfamily with- 
out hesitation the Triassic genus Proganochelys, which has recently been so well 
described by Dr. K. Fraas. Without doubt this genus forms the type of a distinct 
family, the ProganochelyidtP, characterized by the broad shell, the hmder border of 
which is deeply scallopt, by the extremely broad vertebral scutes, by the series of 
supramarginal scutes in front of the first costals and behind the last ones, and by 
the mesoplastra, which meet at the midline and are enormously expanded at their 
outer ends. The genus Proganochelys is the oldest turtle of which we have any 
considerable knowledge, coming as it does from the Keuper, of the Trias. Cervical 
vertebnc of a genus named Chelyzoon have been described by Huene from the 
Muschelkalk of Germany. They have been supposed to belong to the Cryptodira, 
but there is little reason why they should not be referred to the Amphichelydia. 

The most recent certainly known member of this subfamily comes to us from the 
Uinta beds of Utah. Pleurosternon mioccenuni Portis has been described from the 
Tertiary near Lausanne, Switzerland, but it is based on a badly damaged plastron. 

1. Axillary and inguinal buttresses feebly developt. Plastron usually not notcbt behind; 

nusopla.stra usually not narrowed at midline PleurosterntJrc 

2. Axillary and inguinal buttresses strongly developt; mesoplastra narrowing toward midline. . Ba'enidte 

Family PLEUROSTERNID^ Cope. 

A family of Amphichelydia. Carapace with costals articulated to the peripherals by close 
sutures and by gomphosis of ends of ribs. Plastron joined to the carapace by sutures and by 
narrow axillary and inguinal buttresses; the former ascending to the first costal, the latter 
attaining the borders of the fifth and sixth costals at their junction. In Helochelys the union of 
carapace and plastron probably less intimate. Mesoplastrals meeting broadly at the midline, 
not much expanded toward the outer ends. Exposed surfaces of carapace and plastron tuber- 
culated or shagreened. Intergulars and inframarginals present. Skull elongated and pointed; 
the bones mostly finely tuberculated. The cervical vertebrae are biconcave. Coracoids 
distally expanded. 

So far as the writer knows, the name Pleurosternid:e for this family was proposed 
by Prof. E. D. Cope in 1868 (Proc. Acad. Nat. Sci. Phila., p. 282) andwas employed 
by him at various times afterward. He regarded it as a family distinct from the 
BaenidiB. Both families appear to have been always included by him among the 
Cryptodira. Lydekker (Cat. Foss. Reptilia, iii, p. 205) includes in it the Baenidae. 
Baur (Proc. Acad. Nat. Sci. Phila. i8gi, p. 428) thinks it better to leave i5af«a in a 
distinct family, nearly related to Pleurosternon. To the present writer each group 
appears to be worthy of family rank. The genus Helochelys, of the Cenomanian of 
Germany, evidently belongs with the Pleurosternidae. Pleurosternon is found in the 
Purbeck and Portland Oolite of England. A species described by Roemer as 
Emys menkei, from the Wealden of Germany, is believed to belong to Pleuro- 
sternon. Portis has described P. mioccFnuiii from the Tertiary near Lausanne, 
Switzerland. Li our own country, it appears that Glyptops existed from the 
Upper Jurassic through the Lower Cretaceous {G. ccelatus) and the Benton {G. 
pervicax) into the Denver {G. deprcssus) of the uppermost Cretaceous. 

Genus GLYPTOPS Marsh. 

Carapace deprest. Exposed surfaces of the shell rough with small tubercles and twisted 
ridges. Neurals hexagonal, with the broad end m front. Costo-marginal sulci mostly below 
the costo-peripheral sutures. Axillary buttresses reaching border of first costals. Inguinal 
buttresses each entering an excavation at lower borders of fifth and sixth costals. Mesoplas- 



46 FOSSIL TURTLES OF NORTH AMERICA. 

trals joining extensively at the midline. Bridge about twice as broad as long. Inframarginals 
almost wholly on the plastral bones. Plastron with hinder lobe not shortened and not notcht 
behind. Pelvis not suturally articulated with the plastral bones. Skull pointed anteriorly; 
most of its surface bones finely tuberculated. Bones of lower jaw smooth; the symphysis 
short. 

This genus was establisht by Professor Marsh in the year 1890 (Amer. Jour. 
Sci., XL, p. 177), his type being G. ornatus, collected in the Upper Jurassic of 
Wyoming. This species is apparently identical with Cope's Compsemys plicatulus. 
A comparison of specimens of Compsemys victus Leidy with Cope's species just 
mentioned makes it certain that the two forms are not congeneric. Compsemys 
plicatulus must therefore be removed from Compsemys, and Marsh's genus Glyptops 
becomes available. The assignment by Cope of various species of Jurassic and 
Cretaceous turtles to Compsemys was evidently due principally to supposed resem- 
blances in the sculpture; but all of these species, except the type, C. victa, must be 
referred to other genera. There are no evidences that C. victa possest mesoplas- 
tra. The total absence of distal prolongations of the costals for insertion in the 
peripherals of C. victa and their presence in G. plicatulus sufficiently separate them 
genetically. 

To Glyptops is provisionally referred G. pervicax, which in some respects 
approaches more closely Pleurosternon, more especially in having the plastron 
slightly notcht behind. On the other hand, the bridge is longer than in Glyptops 
plicatulus. It is not improbable that it represents an undescribed genus. 

It is to be noted that usually when authors have referred to the genus Compsemys 
they have had in mind the species C. plicatulus, because its characters were well 
known through Professor Marsh's and Dr. Baur's descriptions; whereas, little is 
even now known about C. victa. For these references the writer's Bibliography and 
Catalogue of the Fossil Vertebrata of North America, 1902, p. 437, may be consulted. 

As here employed, Glyptops will include 4 species : the type, G. plicatulus of the 
Jurassic, G. ccelatus of the Lower Cretaceous, G. pervicax of the Benton, and 
G. depress us of the uppermost Cretaceous. Possibly when more is known of the two 
last-mentioned species they will be removed from the genus. 

Glyptops is closely related to Pleurosternon Owen, as already recognized by 
Dr. Baur. However, it differs from the latter in having the hinder lobe of the 
plastron less constricted and without posterior notch, in having the inframarginals 
almost wholly on the plastral bones, in having the costo-marginal sulci well below 
the costo-peripheral sutures, except over the bridges, and in having longer bridges. 
The distance from a line joining the free border of the anterior lobe of the plastron 
with the posterior lobe to the outer end of the mesoplastron is contained in the width 
of the bridge about three times in Pleurosternon and about two times in Glyptops. 

Helochelys is another relative of Glyptops. Its hinder plastral lobe is little more 
than half as long as wide; the plastron appears to have been less closely joined to 
the carapace than in Glyptops; the bridges are short; and the last neural, the only 
one known, is hexagonal, with the broader end directed backward. 

Key to the Known Species. 
A. Jurassic. 

a. Morrison beds plicatulus 

AA. Cretaceous. 

a. Lower Cretaceous. 

h. Potomac beds cctlatus 

hb. Benton beds pervicax 

aa. Upper Cretaceous. 

c. Denver beds ? Jepressus 



PLEUROSTERNID^. 47 

Glyptops plicatulus (Cope). 
Plates 5, 6; text-figs. 17-27. 

Com psemys plicatulus, Cope, Proc. Amer. Philos. Soc, xvii, 1877, p. 196. — Baur, .Amer. Naturalist, 
XXIV, 1890, p. 534; Proc. Acad. Nat. Sci. Phila. 1891, p. 411 ; Anat. Anzeiger, xii, 1896, p. 565. — 
Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 437. 

Glyptops ornatus. Marsh, Amer. Jour. Sci. (3), XL, 1890, p. 177, pi. vii, figs, i, 2; Monogr. U. S. 
Geol. Surv., xxvii, 1897, p. 507, figs. 63, 64. 

The present species is one ot the two oldest known from North America, coming as it does 
from the uppermost Jurassic. The other species which comes from the same deposits is 
Probaena sculpta, but it is represented by only an imperfect shell; whereas Glyptops plicatulus 
is represented by nearly all portions of the skeleton. 

The species had for its type various fragments that had been collected for Professor Cope 
by Mr. O. W. Lucas, at Canyon City, Colorado, from freshwater deposits that were called by 
Professor Marsh the Atlantosaurus beds, by Scott and Knight the Como beds, and by Whitman 
Cross the Morrison beds. Cope's type is No. 6099 of the American Museum of Natural 
History. The principal parts present are one complete costal, apparently the third of the left 
side (plate 5, fig. i), the proximal end of what is regarded as the fifth of the right side, the right 
axillary region, most of the left hypoplastron, and a part of the contiguous left xiphiplastron. 
The supposed third costal is shorter than the corresponding one of the American Museum 
specimen, No. 336, a slightly smaller individual, as shown by the hypoplastra. It might be 
regarded as the fifth were it not that the distal end is crost by the costo-marginal sulcus. The 
vertebral scutes are narrower than those of No. 336. Also the bases of the rib-heads are 
slenderer. The hypoplastral is somewhat longer and at the same time slightly narrower than 
that of No. 336. There is a possibility that we have here two species. The sculpture appears 
to be identical in the two specimens. Baur appears to have examined the type bones and he 
identified them as being the same as Marsh's Glyptops ornatus. 

Professor Marsh's types of his Glyptops ornatus were obtained at Como, Wyoming, from 
deposits regarded as of the same age as those of Canyon City. The remains consisted of a 
skull nearly complete, portions of two other skulls, and portions of the shells of two or three 
other individuals. These were briefly described and figured by Marsh, as cited above. The 
figure of the skull particularly is very poor. This skull had been crusht laterally and hence 
the figure shows it as narrower than it was in life. A side view of the same skull, prepared for 
the U. S. Geological Survey, by F. Berger, is here presented (plate 5, fig. 2). In 1891 Dr. 
Baur, as cited, publisht a more extended description of Marsh's specimens and criticized some 
of Marsh's statements. The writer has examined the skull figured by Marsh. The occipital 
condyle is broken away. The length from the condyle to the tip of the snout was close to 
62 mm. The temporal region was originally rooft over to a perpendicular plane passing 
through the articulations of the quadrate for the lower jaw. The extent of this roof from the 
orbits was 38 mm. The median suture may be traced from the tip of the snout to near the rear 
of the skull. Most of the other sutures are invisible. The supraoccipital spine appears to have 
been destroyed. The orbit is circular, with a diameter of 12 mm. The nasals are distinctly 
separated from the prefrontals and have a length of 4 mm. The premaxillae are small and 
distinct from each other and from the maxillae. What bone forms the septum between the orbit 
and the nasal cavity can not be determined. The maxilla has a thin cutting-edge and a narrow 
triturating surface. This bone extends far behind the orbit and has a length of 33 mm. From 
its hinder end the suture between it and the jugal may be traced upward and forward to the 
border of the orbit. 

On the lower side of the skull is seen the anterior end of the vomer; the remainder is 
broken away. The choanae were placed far forward. The palatines ran forward nearly to a 
line joining the fronts of the orbits. The pterygoids are interposed between the quadrates 
and the basioccipital. Where narrowest the pterygoid portion of the palate is 1 1 mm. wide. 
The articulation of the quadrate for the lower jaw is concave in all directions, most so from 
side to side. 

In the American Museum of Natural History there is a specimen of this species that was 
collected at Bone Cabin quarry, Wyoming, about 10 miles from Como, the locality of Marsh's 



48 



FOSSIL TURTLES OF NORTH AMERICA. 



specimens just mentioned. The number of the specimen is 336. It presents the shell complete, 
the dorsal and the cervical vertebrae, the skull quite complete, the shoulder and pelvic girdles, 
and portions of all the limbs. The skull will be described first. 

When buried the skull was undoubtedly complete, but has suffered somewhat during 
disinterment and preparation (plate 5, figs. 3, 4). The bone is extremely brittle and much 
fractured. On this account, and because ot the roughness of the surface, the sutures are mostly 

undeterminable. The length from the occipital 
condyle to the end of the snout is 66 mm., nearly 
the same as that ot Marsh's specimen. In form it 
is wedge-shaped, but not so narrow as Marsh's 
laterally crusht specimen. The width at the 
quadrates is 48 mm. The supraoccipital spine is 
missing. It is doubtful whether it ever had any 
considerable length. The parietals lack about 5 
mm. of extending backward as far as the occipital 
condyle. The roofing of the temporal region is 
like that of the skull just described. Whether or 
not the parietals join the squamosals can not be 
determined; they probably do. The orbits had a 
diameter of 15 mm., but some allowance must 
be made for distortion; they appear to have 
been larger than those of Marsh's type. The 
interorbital space measures 9 mm. Apparently 
the sutures bounding the frontals laterally can be 
distinguisht, and possibly those limiting these 
bones anteriorly. Nasal bones can not be distin- 
guisht. The maxillary bone is only 3 mm. wide 
below the orbit. The tympanic cavity appears to 
have been small. The stapedial passage was open 
behind. The quadrates appear to have been 
directed slightly forward. The lateral squamosal 
processes extend behind the occipital condyle 
about 5 mm. 

On the upper surface there is observed on 
each side a groove, or sulcus, which starts about 8 
mm. from the midline at the hinder border of the 
temporal roof, runs first forward and inward to 
near the midline, then toward the orbit. Similar 
sulci are seen in Chelydra and it is thus rendered 
probable that the surface of the head was covered 
with horny scutes. 

The basioccipital and the basisphenoid are 
narrow. The suture between the two can not be 
certainly distinguisht. The basisphenoid can be 
traced forward about 30 mm. from the condyle. 
It is 7 mm. wide posteriorly and narrows ante- 
riorly. It is doubtful if the pterygoids came in 
contact at any point. The pterygoid region, where 
narrowest, is 14 mm. wide. Toward the anterior 
end of the basisphenoid there is on each side, 
Fig. 17. — Glyptops pUcatulus. Carapace, xj. between this bone and the pterygoid, a foramen. 
No. 336 A. M. N. H. Shows the various such as is seen in Bn'ena, probably for the passage 
bones and many of the scutes. of a vein. In the skull here described a groove 

Fig. 18. — Glyptops pUcatulus. Carapace, xj. proceeds backward for some distance, and the 
No. 1357 Yale University. Shows onlv the appearance is such that the presence of a slit 
bones. Figure from U. S. G. S. between the bones is suspected. The ectoptery- 




PLEUROSTERNID^. 



49 



goid processes are very large. The anterior region of the roof of the mouth is damaged, 
so that httle is to be learned from it. 

The lower jaw is closely prest against the remainder of the skull. From its tip to the 
hinder end is 54 mm. The two rami are co-ossified. The symphysis is 10 mm. long. All the 
bones are smooth. 

Here it may be permitted to make some remarks on Baur's description of the 
skull of this species. The sculpture of the bones is not exactly like that of the shell, 
it being finer and more pustular. Baur, in opposition to Marsh, states that the 
exoccipitals take part in the formation of the condyles. It seems probable that 
Baur came to this conclusion from the presence of the pit, making the assumption 
that this is found only where the basioccipital meets the exoccipital. In the skull 
of a Bridger Baena the basioccipital takes no part in the condyle, and yet there is a 
very distinct pit. The skull of Glyptops in the American Museum does not enable 
us to decide the question. 

Portions of 7 of the cervicals are preserved in the American Museum specimen, the first 
not being present. As a whole, the neck seems to have been short and slender. Its total 
length did not exceed 120 mm., the carapace being 300 mm. The articular end of the second 
cervical has a diameter of only 4 mm., while that of Trachemys elegans, with a carapace 230 mm. 
long, has a diameter of 5 mm. All the cervicals present a deep, comprest, and sharp keel along 
the lower side, thickening behind. All, excepting probably the first, possest transverse pro- 
cesses, each about 4 mm. long. All have the anterior and posterior articular surfaces more or 
less concave. The hinder end of the eighth is concave, without the convex portion men- 
tioned by Dr. Baur. The anterior end also is concave. The postzygapophyses are close 
together, but have not coalesct. The hinder end of the seventh is nearly flat, and we may 
suppose that it has entered on the first stages in forming a convex articulation. Barring the 
articular surfaces, these cervicals resemble closely those oi Baena. 

The first dorsal vertebra has a very distinct keel along its lower side and the anterior end 
of the centrum is concave. The first rib is long, about 57 mm., and has apparently lost a 
portion of its extremity. It has a diameter of about 5 mm. and is applied closely to the rib of 
the first costal plate. The rib-heads are much like those oi Baena. The one belonging to the 
first costal plate is the broadest, about 12 mm. in diameter. Most of the others are smaller, 
about 8 mm. wide. The last two are considerably smaller. The tenth rib is short and thick, 
its length being 15 mm., its diameter 4 mm. Its outer end is somewhat enlarged, to support 
the ilium, and it is applied against the lower surface of the eighth costal. The first sacral rib is 
the larger, about 20 mm. long, and expanded at its outer end to a width of 10 mm. The 
second sacral rib is much slenderer. Both of them resemble corresponding parts of Chelydra 
and Baena. 

The carapace (plate 6; text-fig. 17) is 300 mm. long in the midline, and 272 mm. wide. It 
is much deprest, but this is due to some extent to distortion during burial, for some of the 
costals and peripherals are spread apart. Anteriorly the border is slightly excavated in the 
midline. Posteriorly the carapace is truncated and broadly and shallowly excavated. Marsh's 
figure represents his specimen as more rounded behind. The peripherals extended outward 
nearly horizontally. Their borders are subacute near the midline in front and behind, but 

they thicken and become more obtuse toward and over the 
bridges. The whole surface of the carapace and of the plastron 
is finely sculptured with tubercles and winding ridges, there 
being about 12 ridges in a line 10 mm. long. 

The nuchal bone is quadrilateral, with the broadest side 
joining the first costals and the first neural. This side is 80 
mm. long. The free border is 42 mm. long. The accompanying 
table presents the dimensions of the neurals. 

There is in this specimen a single suprapygal. Baur states 
that in the Yale specimens there are two of these bones, but 
Marsh figures only one. A sketch in the writer's possession. 



Neural. 


Length. 


Width. 


, 


38 


^3 


2 


3° 


z6 


3 


3^ 


24 


4 


z6 


^3 


5 


27 


^3 


6 


19 


>9 


7 


18 


20 


8 


ig 


21 



50 



FOSSIL TURTLES OF NORTH AMERICA. 



made apparently for Dr. Baur, and here reproduced (fig. i8), represents the first as small and 
occupying the space between the costals of the eighth pair. The suprapygal of No. 336 is 
large. Its length is 36 mm., its width anteriorly 14 mm.; the maximum 64 mm.; the posterior 
width 38 mm. This bone somewhat resembles in form that of a Testudo. 

The costal plates narrow in succession backward. The peripherals are 11 in number on 
each side. Anteriorly and posteriorly they are high; over the bridges they are low. The 
first and second have a height of 35 mm.; the fifth, 18 mm.; the ninth, 40 mm. 




Figs. 19-27. Glyptops plicatulus. No. 336 A. M. N. H. 

23. Felvis Irom below. X^. Somewhat crusht 



19. Plastron. X J. Shows bones and many of the 

scute areas. 

20. Scapula. X if • Procoracoid process, on the 

right, shortened by crushing. 

21. Coracoid and procoracoid process of scap- 

ula. XJ. 

22. Right humerus. X?- Dorsal surface. 



Pelvis from below, 
fore and aft. 

24. Pelvis from left side. X§. 

25. Right femur. X§. From tibial border. 

26. Right femur. X§. From dorsal surface; some- 

what crusht. 

27. Digital bones. Xi- 



The plastron is flat (fig. 19). Its length is 260 mm. The anterior lobe is 80 mm. long; 
its width at the base, 122 mm. The edges are thick and rounded. The bones at the epihyo- 
plastral suture are 8 mm. thick. The entoplastron is 43 mm. long and 47 mm. wide and 
broadly rounded behind. The hyoplastrals meet at the midline about 50 mm. The meso- 
plastra differ in width at the midline, the left being 30 mm. wide, the right 22 mm. The 
hinder lobe is 78 mm. long and 106 mm. wide at the base. The hinder border is truncated. 
The free borders are acute-edged. The bone thickens rapidly from the borders to about 10 mm. 

The plastral bones are joined to the bridge peripherals by the usual rough sutures. Strong 
buttresses rise to the costals. 

The sulci bounding the epidermal scutes are extremely obscure and in many places can 
not be determined. Where they can be observed they have been represented in the diagram- 
matic figures. Those of the plastron are less difficult of observation. The gular scutes are 
very broad, the sulci bounding them posteriorly curving outward and backward to near the 
epihyoplastral suture. The intergulars can not be made out on No. 336, but they are shown 
by Baur in a figure furnisht for him by the United States Geological Survey (plate 5, fig. 5). 



PLEUROSTERNID^. 5I 

These intergulars slightly overlap the entoplastron. The humero-pectoral sulcus passes 
behind the entoplastron. Dr. Baur's figure of the median sulcus represents it as running an 
exceedingly irregular course. In fig. 19 this sulcus is probably represented much too straight. 
On the bridges are very distinct inframarginals, as represented in fig. 19. Only the angles 
of these extend over on the peripheral bones. 

Dr. Baur states that a nuchal scute is present in this species, but in No. 336 it can not 
be distinguisht with certainty. On most of the peripherals the sulci may be seen, both on 
the upper and the lower sides. The boundaries of the three anterior vertebrals have been 
determined quite satisfactorily. The width of these scutes is about 90 mm. 

Dr. Baur has briefly described the shoulder-girdle. This is present in specimen No. 336 
(figs. 20, 21) altho the distal portions of the coracoids are damaged so that their exact form 
can not be determined. The left half of the girdle is least injured and distorted. Here we 
find the scapula, the procoracoid process, and the coracoid standing at nearly right angles with 
one another. In this respect they are much as in Chelydra. The scapula is relatively shorter 
than in Chelydra, and the procoracoid is shorter still. The lower end of the scapula is strongly 
comprest. The glenoid fossa is removed outward some distance from the perpendicular 
portion of the scapula. This fossa presents some interesting peculiarities. It measures 7 mm. 
by 9 mm. and it has the long axis directed nearly horizontally. The fossa of Chelydra, nearly 
of the same shape, is directed nearly perpendicularly. Furthermore, there is, running along 
near the lower border of the fossa, a prominent ridge, which is found to correspond to a groove 
on the head of the humerus. Nothing of the kind is found in either Chelydra or Testudo, 
except in the most rudimentary form. However, in a specimen of Trachemys rugosa there are 
found similar structures; but here too, the long axis of the fossa is directed strongly upward. 
Examination of the naturally articulated parts of Trachemys shows that the motion of the 
humerus is nearly confined to a plane which is directed backward and downward. The 
motion of the humerus of a Testudo, with its round head, is much more free and varied. The 
Testudo is a tortoise adapted solely for walking; the Trachemys is to a great extent a swimmer. 

Dr. Baur states that the fore limb of Compsemys {Glyptops) is long and resembles the 
elements of the Emydidae. However, the humerus (fig. 22) is a little shorter proportionally 
than in Trachemys rugosa and the limb is rather feeble. The humerus is but little more than 
one-half as long proportionally as that of Chelydra. The bone is, however, not so slender 
as that of Trachemys, but has more of the form and proportions of Chelydra. This applies 
also to the size of the radial and ulnar tuberosities. The distal end of the humerus has points 
of interest. Its breadth is like that of Chelydra. There is distinct evidence of the presence 
of a deep coronoid depression. The ectepicondylar foramen pierces the bone at a distance 
of 1 1 mm. above the condyle. The trochlear surface reminds one of that of some mammal. 
Instead of forming an elongated smooth surface, convex in both directions, it presents two 
prominent ridges separated by a groove. The distal end of the humerus of Trachemys rugosa 
presents a somewhat similar structure, but the guiding ridges are far less prominent. As in 
Glyptops, the most prominent one is that for the head of the radius. The result of these 
arrangements must be that the motion of the forearm of both genera is confined to one plane, 
like that of the forearm of a man. 

There is this difference, however, between the humeri of Trachemys and Glyptops. In 
the former these ridges run nearly parallel with a plane passing through the long axis of the 
head of the humerus. The effect of this is to make the forearm move in the same plane as 
the upper arm; that is, downward and backward. In Glyptops, on the other hand, ths ridges 
of the trochlear surface are directed at an angle of about 45° with the plane of the head of the 
humerus. Hence, when the limb is drawn backward, the humerus moves in a horizontal 
plane, while the forearm, if flext, would move downward and backward. 

One ulna is present. It is slightly longer proportionally to the humerus than it is in 
Trachemys, and its distal end is broader. Of the hand the writer can say nothing. 

Baur has dealt with the pelvis without figuring it. He errs with regard to the inner ramus 
of the pubis, when he says it is a slender element and that the ischium is larger than the pubis. 
The contrary is true (figs. 23, 24). The pubis, aside from the lateral processes, does not differ 
greatly from that of Chelydra or Testudo. In the specimen before me it has an antero-posterior 
extent of at least 25 mm. It is quite deeply notcht in front. Baur is possibly, but not certainly 



y 



52 



FOSSIL TURTLES OF NORTH AMERICA. 



correct when he states that it did not come in contact in the midline with the ischium. The 
pelvis in the specimen here described has probably suffered some antero-posterior crushing, 
but the pubes and ilia do join. In Baena, whose pelvis is identical with that of Glyptops, 
there is, at least in aged individuals, a union of these elements in the midline. 

The lateral pubic processes are quite different from those o{ Chelydra, being more massive. 
At their extremities, where they come into contact with the xiphiplastra, they are enlarged and 
rough. Above this they are constricted into a sort of neck. The ischium is narrow from front 
to back, about 12 mm., and thin, as in Baena. Its hinder lower border is nearly straight until 
the processes are reacht on which thg ischium rests on the plastron. These processes stand 
at a distance of 30 mm. apart. Each is terete, pointed at its free end, and about 15 mm. long. 
They are directed backward. 

The ilium is not greatly different from that of Chelydra, except that it is shorter and 
proportionately stouter. The sacrum is in general smaller and weaker than that of Chelydra, 
except that the distance of the acetabula apart is the same. The pelvis is essentially like that 
of Baena and all parts should be compared with those of the latter genus. 

The only portion of the hind limb present is the right femur and probably some foot bones. 
Dr. Baur states that the femur agrees with that of the Emydidae. In length, it is exactly that 
of the Trachemys mentioned and relatively much shorter than that of Chelydra. It is much 
curved, especially toward the distal end (figs. 25, 26). The greater trochanter is separated 
from the lesser by a deep fossa. From the greater trochanter a prominent crest runs down 
on the hinder side of the femur one-third or more of its length. The distal end of the femur is 
damaged, but it presents indications of having had the condyles more prominently developt 
than in turtles in general. The total length of the femur in a straight line is 61 mm. 

One complete toe, which probably belonged to a hind foot, is preserved with the parts in 
place (fig. 27). It shows a metatarsal and three phalanges, and these have a total length of 42 
mm. The metatarsal is slender and has a length of 22 mm. 





31- 



Figs. 28-31. Glyptops ccclatus. Type specimen in U. S. N. M. 



28. Portions of first and second peripherals and 

first costaL Xi- 

29. Section across second peripheral. Xf. 



30. Section across hinder peripheraL 

31. Proximal end of costal bone, showing scute 

areas and sculpture. X J. 



Glyptops caelatus sp. nov. 
Plate 7, figs. I, 2; text-figs. 28-31. 

The fragments of tortoise to which this name is given were collected by Mr. J. B. Hatcher, 
in 1887, at Muirkirk, Maryland, in deposits belonging to the Potomac formation of the Lower 
Cretaceous. The fragments consist of portions of costals and of peripherals. The most 
important fragment consists of the right first costal, a part of the first and most of the second 
peripherals. There is also a part of a costal situated further back in the carapace. These 
bear the number 1930, and belonged doubtless to one individual. There is present also a 
hinder peripheral and a first right peripheral which have the number 1939. There are also 
two fragments of costals of a young individual, one of which shows the rib-head. The bones 
beanng the number 1930 are regarded as being the type of this species. All the specimens 
are in the United States National Museum. 



PLEUROSTERNID^. 53 

The first costal (plate 7, fig. i; text-fig. 28) has a length, from its union with the neural 
to the pointed distal end, of 103 mm. and a width, fore and aft, of 50 mm. The thickness of 
the costal at the posterior border is about 5 mm. The anterior half of the bone is thickened 
to as much as 18 mm. to form a shoulder for the reception of the axillary buttress of the plastron. 
The latter must have been considerably more strongly developt than in Glyptops plicatulus. 
The head of the rib is stout. The first rib lies in front of and against the rib of the first costal 
plate. The first peripheral lacks its anterior half so that its antero-posterior extent can not be 
accurately determined. However, the missing portion is partly supplied by No. 1939. The 
anterior, or free, border is obtuse. At one end is the sutural surface for union with the nuchal 
bone. It appears quite unlikely that there was any considerable excavation in the front of the 
carapace for the neck of the animal. The first peripheral of No. 1930 was 30 mm. wide, 
parallel with the edge of the shell. The second peripheral has a fore-and-aft extent of 40 mm. 
and the width along the free border is the same. This border also is obtuse (fig. 29) and at a 
short distance from the edge the thickness is about 8 mm. It resembles very closely the 
corresponding one in G. plicatulus. 

The posterior peripheral, probably the tenth of the right side, numbered 1939, is 39 mm. 
wide from the free border to the union with the costal, and 35 mm. along the free border. 
Its thickness, where it joined the costal, is 10 mm., and it has come down to an acute free 
edge (fig. 30). Its form is therefore that of a thin wedge. 

The fragment of costal numbered 1930 (plate 7, fig. 2; text-fig. 31) shows neither the 
length nor the breadth. The piece is 35 mm. wide and has an epidermal sulcus running 
parallel with the sutural border and 27 mm. distant from it. The costal was therefore of 
considerable total width. Its thickness is only 5 mm. The true rib does not appear on the 
lower surface, as it does in G. plicatulus. 

The sulci of this species are narrow and shallow, but quite distinct. Apparently the 
epidermal scutes resembled those of G. pi icatulus, nhho neither the vertebrals nor the marginals 
were so broad as in the latter species. 

The sculpture of the surface is quite different from that of G. plicatulus. In the latter it 
has a more granular appearance and is produced by distinct raised dots and by short ridges 
formed of coalesct dots. In G. aelatus the dots are larger, the ridges also broader, longer, and 
smoother. The spaces between the elevations are as wide as the latter. In the centers of the 
bony surfaces the ridges are irregular in length and direction, and often vermiculate. Border- 
ing the sutural edge is a broad band in which the ridges and grooves run at right angles with 
the suture. On the costals this band may be as much as 13 mm. wide. 

Glyptops? belviderensis (Cragin). 
Plate 7, figs. 4, 5. 

Plesiochelys belviderensis, Cragin, Colorado Coll. Studies, v, 1894, p. 71, pi. ii, figs. 1-8. — Hay, 
Bibliog. and Cat. P'oss. Vert. N. A., 1902, p. 439. 

The present writer has not seen the type specimens of this species. They belong to Colo- 
rado College, Colorado Springs, Colorado. They consist of two first costals, fragments of other 
costals, a neural bone and a dorsal vertebral centrum. These bones were found in the Kiowa 
shales, a portion of the Comanche series and near the top of the Lower Cretaceous. The 
locality is near Belvidere, Kiowa County, Kansas. 

Dr. Cragin referred these bones to the genus Plesiochelys, but there appears to be no special 
reason for this assignment. The species of this genus, so far as certainly known, belong to the 
Jurassic, Kimeridge, and Wealden of Europe. The sculpture of the costals of Cragin's species 
suggests Glyptops calatus and accordingly the species is referred with doubt to Glyptops. Two 
of Cragin's figures are here reproduced. Fig. 5, plate 7, represents a neural seen from the 
under side. It is relativelyconsiderably broader than theneuralsof P/^j/oc A^/jyj (Zittel 's Hand- 
buch Palaeontologie, p. 545, fig. 502; Lydekker's Cat. Foss. Rept., pt. in, fig. 44). The front 
costals figured by Cragin are narrow, the width being 38 mm., the length 82 mm. The longest 
costal was 1 1 1 mm. long. The upper surface of the shell is said to be ornamented with deli- 
cate vermicular grooving and pitting. Fig. 4, plate 7, is intended to represent this sculpture 
of the costals. 



54 



FOSSIL TURTLES OF NORTH AMERICA. 



Glyptops pervicax sp. nov. 

Text-fig. 31. 

The type of the present species is No. 1018 of the American Museum of Natural History. 
It was collected by Mr. Barnum Brown, in 1902, from near the base of the Graneros shales of 
the Benton deposits, in Yellowstone County, Montana. These shales are of marine origin. 
The locality more exactly described is on Brush Creek, 10 miles east of Pryor, in the county 
named. The remains consist of the front and the dorsal region of the carapace and the greater 
part of the plastron. The shell is that of an aged individual. Not a trace appears of the sutures, 
so that the structures can not be in all respects accurately determined. 

The carapace had a length of about 375 mm. There was apparently a broad, low, rounded 
ridge running along the back in the areas of the second, third and fourth vertebral scutes. 
At the midline of the front, over the neck, there was a rounded excavation. The anterior free 
border was obtuse and about 10 mm. thick. The sulci are obscure, due mostly to an adhering 

incrustation of clay, but some of them can be traced. Portions of 
the second, third and fourth vertebral scutes may be mapt out. 
They were considerably broader than long. The third was 83 mm. 
long and had a maximum width of 130 mm. 

On the visceral surface of the carapace may be seen the bases 
of the rib-heads. These were not so strongly developt as in G. 
plicatulus. In the latter, as shown in No. 336, A. M. N. H., the 
rib-heads have a diameter of 10 mm., while in G. pervtcax the 
diameter is about 7 mm. in a larger individual. The whole series 
is shown, on one side at least. The extremity of the tenth rib 
was co-ossified with the eighth costal about 10 mm. behind the 
rib-head of the costal named. On the first costal plate there is a 
prominent ridge which ran from the first and second vertebral 
centra to the border of the third peripheral and met the buttress 
of the plastron. At the peripheral this ridge has a width of about 
18 mm. and a thickness of 11 mm. How high the buttress 
ascended can not be determined, for the suture is obliterated. 
It appears that the buttresses and the costal ridges meeting them 
were more strongly developt in this species than in G. plicatulus. 
The total length of the plastron (fig. 32) was very close to 
335 mm. The anterior lobe is broadly rounded in front, as it is in G. plicatulus. Its length 
is 85 mm., its width about 150 mm. The free border is obtuse. The bone is about 10 mm. 
thick. The limits of the entoplastron can not be determined. On the upper surface of this 
lobe, about 18 mm. behind the anterior border, there are two low processes, one on each side 
of the midline, which were probably for ligamentous attachment of the procoracoid pro- 
cesses of the scapula. In G. plicatulus the corresponding processes are about 34 mm. from 
the border. 

The bridge has a width of 140 mm. Its inner end starts from a low ridge which runs from 
the free border of the anterior lobe to that of the posterior. The outer ends of the bridges are 
mostly missing. 

The length of the posterior lobe was approximately 1 10 mm.; the width at the base, 142 mm. 
The free borders are acute on a level with the lower surface. From this edge the bone is beveled 
and rises to a thickness of 12 mm. Beyond this, toward the midline, the thickness diminishes 
again. At the hinder end of the lobe the thickness is only 5 mm. Most of the hinder 
extremity of the lobe is missing. A small fragment is present, but on account of some doubts 
it has not been used in the figure. On the upper surface of the lobe, very close to its border, 
there is a circular depression about 7 mm. in diameter, which received a process of the ischium. 
On the same surface about 60 mm. behind the inguinal notch, begins another depression, con- 
siderably larger, for the reception of the pubis. 

Most of the plastral scutal areas can be mapt out. The intergulars measured 32 mm. 
along the midline. Taken together, they had a width of about 28 mm. It can not be determined 
certainly whether or not they were divided at the midline. The gulars, as in G. plicatulus. had 




Fig. 32. — Glyptops pervicax. 
Plastron of type. X J. 
Shows scute areas. No. 
1018 A. M. N. H. 



PLEUROSTERNID^. 



55 



been crowded out of contact with each other. The humerals measured 47 mm. at the midline; 
the pectorals, 63 mm.; the abdominals, 54 mm.; the femorals, about 78 mm. There were 
doubtless inframarginals on the bridges, but the sulci are obscure. 

Since the preceding description was written a second specimen has been made available 
for study. This was collected by Mr. Barnum Brown, in 1904, in the Crow Reservation, 
Montana, at a point about 50 miles southeast from Billings and about 25 miles east of Pryor. 
The catalog number of the specimen in the American Museum is 6071. It furnishes more of 
the shell than does the type, but unfortunately the plastron is fractured and faulted obliquely 
to its length and the carapace is fractured and faulted in several directions. 

The carapace was about 325 mm. long and the width is close to the same. The anterior 
border is preserved on each side to behind the axillary notches; it is obtuse and about 10 mm., 
thick. The surface presents the same kind of sculpture as the plastron, consisting of low wind- 
ing ridges. The sulci are rather obscure, but the vertebral scutes were broad, as in the type, 
while the right third costal is seen to have been only 70 mm. high. 

The length of the plastron appears to have been close to 295 mm. The bridge is 125 mm. 
wide. From the line joining the free borders of the anterior and posterior lobes of the plastron 
the bridge rose to the free border of the carapace, a distance of about 1 10 mm. The hinder 
lobe has a width of 125 mm. and a width of 1 10 mm. at its base. At theendsof thefemoro-anal 
sulci the width is 83 mm. The hinder border confirms the accuracy of fig. 32. On the bridges 
are some indications of inframarginal scutes, too obscure to be traced. 





ing.h 



Figs. 33 and 34. Glyptops depressus. Specimen in U. S. N. M. 

33. Carapace of type. Xi- 

34. Portion of plastron of type. Xi* ax-b^ axillary buttress; ent, entroplastron; epi, epiplastron; /ryo, 

hyoplastron; Ay^o, hypoplastron; m^. fc, inguinal buttress; m«j, mesoplastron, 

Glyptops depressus sp. nov. 

Text-figs. 33, 34. 

The type of this species belongs to the United States National Museum. It appears to 
have been secured by one of Professor O. C. Marsh 's collectors in 1889, inasmuch as it bears 
his packing number "1998. Box 3." With the specimen comes a statement by Mr. Whitman 
Cross, of the United States Geological Survey as follows: 

"'No. 2 Box B. '89,' (Cannon's designation). An isolated fragment. (I think this fossil is 
from the Denver beds, from the nature of the sandstones between the shells and the apparently 
zeolitic material in cells of the bone.)" 

Professor Marsh has recorded Compsemys plicatida from the Denver beds, but whether on 
the evidence of this specimen can not be determined. The probabilities that the same species 
is found from the top of the Jurassic to the top of the Cretaceous are remote. 
• • The specimen presents considerable portions of the carapace and of the plastron. The 



Neural. 


Length. 


Width. 


I 


12 


9 


2 


•3 


>3 


3 


12 


M 


4 


II 


H 


5 


lO 


I2.S 


6 


'5 


14 


7 


I4± 


>5± 



r6 FOSSIL TURTLES OF NORTH AMERICA. 

hinder end of the carapace has, at the time of burial, been crusht down to the plastron. After 
having been weathered out of the matrix the specimen suffered further damage, all that part 
behind the seventh neural having been destroyed. All the peripherals are likewise missing. 
The length of the carapace (fig. 33) was originally about 120 mm.; the width was about 
I ID mm. The shell is deprest and was so probably during life. The surface of the carapace 
presents indistinct evidences of having been sculptured finely as in G. plicatulus, or possibly 
more like Compsemys victa. The anterior border of the nuchal bone is eroded away. The 
width of the bone was close to 38 mm. Its form is quite different from that of G. plicatulus. 
In the latter the postero-lateral borders are nearly parallel with each other, while in the present 
species they make nearly a right angle. The accompanying table presents the dimensions 
of the neurals present. 

The great relative width of these neurals as compared with those of G. plicatulus is striking. 

The proximal end of the first costal is 14 mm. wide, while 
the width at the middle of the length is 26 mm. In G. plicatulus 
the median width is little more than the proximal. The succeed- 
ing costals, at the middle of the length, measure as follows: 
The second, 14 mm., the third, 14 mm., the fourth, 12 mm., 
the fifth, 1 1.5 mm., the sixth, 19 mm. The third expands 
distally to nearly 20 mm. The width of the sixth is relatively 
much greater than that of G. plicatulus, but it corresponds to 
the increased length of the sixth neural. 

The anterior lobe of the plastron appears to have been 
rounded like that of G. plicatulus. The epiplastra are badly 
eroded, but the width of each is 13 mm. The entoplastron is 22 mm. long and 26 mm. wide. 
The antero-lateral borders come together to form an obtuse angle; the hinder end of the 
bone is more pointed. The mesoplastra are relatively broader fore and aft than those of G. 
plicatulus. That of the right side is about 15 mm. wide at the midline; but it expands later- 
ally, so that at the middle of its length the width is 24 mm. That of the left side is 23 mm. 
wide at the midline, but narrows laterally for a short distance. The remainder is missing. It is 
remarkable how close the hinder border of the mesoplastron comes to the inguinal buttress, 
differing in this respect much from G. plicatulus. 

There are evidences of rather strong axillary and inguinal buttresses. They appear to 
have articulated with the distal ends of the fifth and sixth costals, at their junctions. 

On account of the weathering to which this shell has been exposed, the boundaries of the 
scutes can not be determined. 

Family BAENID.* Cope. 

Amphichelydia having the plastron firmly joined to the carapace by sutural union with the 
lateral peripherals and with the costals by strongly developt axillary and inguinal buttresses. 
Mesoplastra usually meeting at the midline and expanding toward the outer ends. Skulls, so 
far as known, broad and short. Temporal roof extensive. Neck short, most of the vertebral 
centra with only one end concave. 

To this family are assigned provisionally the genera Polythorax Cope and Archteochelys 
Lydekker. The former possest intergular and interhumeral scutes; the latter genus appears to 
have had a complete series of median plastral scutes. 

The Ba'enida; are closely related to the Pleurosternidee, but the great advances made in the 
structure of the cervical vertebrae and the extension of the plastral buttresses seem to set the 
species off as a distinct family. 

According to our present knowledge this family had an existence extending from the 
Upper Jurassic to the Upper Eocene. Proba'ena, a close relative of Platychelys, of the Upper 
Jurassic of Europe, has been described from the Como, or Morrison beds, occurring there with 
Glyptops. Species belonging to Ba'ena are now known from the Judith River beds, the Lara- 
mie, and from all the divisions of the Eocene to the Uinta. Boremys Lambe comes from the 
Judith River deposits, Euba'ena from the Laramie, and Chisternon from the Bridger. 

Baena appears to be the genus most prolific of species and in most respects the one most 
advanct. The carapace possesses a series of 8 neurals and a corresponding number of costals. 



BAENID^. 57 

a nuchal, I2 pairs of peripherals, and what must be regarded as a suprapygal, but no true 
pygal. The plastron has, besides the bones found in the Emydidae, a pair of mesoplastrals, 
which usually reacht the midline and expanded greatly outward to join the fifth and sixth 
peripherals. The axillary and inguinal buttresses are high and wide. Between the axillary and 
the inguinal of each side there is a large sternal chamber. The axillary buttress ascended to 
a point a little above the lower border of the first costal, meeting there the comprest rib of 
the first dorsal vertebra. The inguinal buttress rose above the lower border of the fifth and 
sixth costals and was articulated in a ridge rising from the adjacent borders of these costals. 

The scutes of certain regions of the shell are extremely variable; in other regions they vary 
little. On the carapace it is the area occupied in the Emydidae by the first vertebral, the nuchal, 
and the first pair of costals that is subject to variation in its scutes. There may be on each side 
a supernumerary first costal scute, or it may occur on only one side, or it may be wholly absent. 
In some specimens is a second pair of supernumerary costals, lying just behind the nuchals. 
There may even be a supernumerary vertebral cut off from the front of the normal first 
vertebral. 

On the plastron the gulars and intergulars are variable in form and size. The infra- 
marginals vary in number and size and form. There are usually 4, but often the second from 
the axillary notch is missing on one or both sides. In this case the pectoral scute may or may 
not reach the marginals. 

In Chisternon there Intervenes between the nuchal bone and the first neural a large bone 
that is not present in Ba'ena (fig. 76). This the writer calls the preneural. In this genus too the 
occasional variations in the scutes of the front of the carapace appear to be quite the rule. The 
normal first vertebral scute is transversely divided, so that there are 6 vertebrals. There is 
usually on each side a supernumerary costal and sometimes two of them, making 6 pairs of 
these. The same variations occur in the scutes of the plastron of this genus that we find in 
Ba'ena. In one case there are 5 inframarginals. 

It would be worth much to know the meaning of these variations in the bones and scutes. 
Is the presence of the preneural in Chisternon a primitive or a secondary condition ? The writer 
does not regard it as probable that a bone like the nuchal has become secondarily divided, or 
that a new bone has become develop! in that region. It appears more probable that both it and 
the nuchal are continuations forward of the row of neural bones, and that in the most 
advanct turtles the preneural has been crowded out of existence by the growth of the nuchal. 
It is evidence in favor of this view that in Boremys Lambe there is present a small preneural; 
also that it is present in the trionychoid genera Aspideretes and Plastomenus. These genera 
have probably inherited this bone from their Amphichelydian ancestors. 

As regards the supernumerary scutes, we have the same questions to answer as in the case 
of the prenuchal. Do we have here a breaking up of the normal scutes into smaller areas, as has 
been observed in some modern genera by H. Gadow, W. P. Hay,and R.E. Coker; ordowe have 
the normal number of scutes that were present in the earlier turtles, together with a tendency 
to a suppression of some of them ? We must recognize the fact that on most parts of the shell 
the scutes are as stable as in ordinary turtles; altho, especially on the plastron, there is a ten- 
dency for the sulci to wander somewhat wildly. It is to be noted that the variations occur in 
those regions where, in modern turtles, certain scutes have been supprest. There can be no 
doubt that intergulars were primitively a possession of all turtles, but in most Cryptodira they 
have been supprest. The primitive turtles likewise possest on each bridge a complete row of 
inframarginals; but in most living genera these have been eliminated, with usually the excep- 
tion of an axillary and an inguinal scute. There is probably not so much evidence that one or 
more anterior costal scutes have been supprest. In H. von Meyer's representation oiAcichelys 
crassipes (his Palceomedusa testa, Lithogr. Schiefer, pi. xx, fig. i) there is shown a pair of super- 
numerary costal scutes. It is also interesting to observe in that specimen 2 neurals between the 
first pair of costal bones. The anterior of these is probably the preneural. In the modern 
genus Caretta there are 5 pairs of costal scutes. It appears probable that the preneural and 
the supernumerary anterior vertebral scute tended to disappear together. 

The skull of the Ba'enidce presents various primitive features. The presence of distinct 
nasals, of lacrimals, and a wide temporal roof is to be cited. The writer has not found 
epipterygoids. The short supraoccipital is likewise primitive. When we leave aside these 



^8 FOSSIL TURTLES OF NORTH AMERICA. 

characters the skull appears to be cryptodiran in structure. The neck must be regarded as 
primitive and intermediate between the Cryptodira and the Pleurodira. No features strictly 
pleurodiran appear. 

The cervical vertebrae are described under the species Baena riparia and Chisternon 
hebraicum. Considering the shortness of the neck, the structure of the vertebrae, and the nar- 
rowness of the anterior border of the carapace, it seems probable that these turtles were able to 
find in the shell little protection for their heads. 

The tail was long, resembling that of Chelydra. With two or three of the skeletons there 
have been found some conical bones, the bases of which were buried in the skin. Some of 
these are symmetrical and it appears probable that they were placed in a row on the upper 
midline of the tail, as in Chelydra. Others of these bones are unsymmetrical, and possibly 
formed parts of lateral rows on the tail. If there had been an armor of dermal bones on the 
legs it would probably have been observed in some of the specinjens. 

For the shoulder-girdle and the pelvis the reader is referred to succeeding descriptions of 
Baena and Chisternon. The limbs are of the walking type. 

The following key may be of some use in determining the genera of the family: 

A. No interhumeral scute. 
a. A preneural present. 

b. No supramarginal scutes Chisternon 

bb. Supramarginals present Boremys 

aa. No preneural so far as known. 

c. Plastron projecting little, if at all, beyond front of carapace. 

d. Skull with choanx well in front Baena 

dd. Skull with choanae between orbits Euba'ena 

ddd. Skull unknown. Plastron with median fontanel Probaena 

cc. Front of plastron projecting in front of the excavated carapace. 

e. The axillary and inguinal buttresses not greatly developt Thescelus 

ee. Axillary buttresses rising high on first costals Charitemys 

aaa. Characters not well known. A suprapygal present; the vertebral scutes broad; 9 pairs 

of costals in type Neurankylus 

AA. Plastron with an interhumeral scute. 

a. Outer surface of plastron rugose Polythorax 

aa. Outer surface of plastron with globular elevations Naomichelys 

Genus PROBAENA Hay. 

A genus closely related to Baena, but with a more deprest carapace, the hinder border of 
which is little or not at all notcht. Vertebral scutes broader than the costal scutes. Plastron 
with its hinder lobe rounded. A fontanel (permanent ?) between inner ends of mesoplastra. 

It is not improbable that when the skull and the cervical vertebrae of this genus shall be 
discovered, it will prove that it belongs to the Pleurosternidae and that the Baenidae had not yet 
diverged from the former family. 

Probaena sculpta Hay. 

Plate 7, fig. 5. 
Probaena sculpta, Hay, Ann. Carnegie Museum, 11, 1903, p. 201, plate iii, figs. I, 2. 

The type is a small and somewhat imperfect turtle, represented by about three-fourths of 
the carapace and the greater portion of the plastron. 

It belongs to the Carnegie Museum, Pittsburg, and was collected by Prof. J. B. Hatcher, 
in 1901, in the "Marsh quarry" in the lower portion of the Morrison, or Atlantosaurus beds, 
8 miles north of Canyon City, Colorado. The catalog number is 917. 

The length of the carapace is at present 105 mm., very near the original length; the 
width is 70 mm. The shell has apparently been rather flat, but probably somewhat less so in 
life than at present. The greatest distance between the upper and the lower surfaces is now 27 
mm. The borders of the carapace behind the inguinal notches are considerably flared upward, 
but this may be due somewhat to post-mortem distortion. This border appears to have been 



BAENID^. 59 

little or not at all notcht, except in the midline behind, where there is a slight excavation. 
In the nearly smooth hinder border this genus differs from the species oi Ba'ena. 

Most of the sutures and of the epidermal sulci are obscure; and in most parts of the cara- 
pace the sutures are incapable of determination. The sulci bounding the second, third, and 
fourth vertebral scutes are satisfactorily seen. These scutes were very broad, each about 34 
mm.; while the costal scutes were only about half as wide. The areas occupied by the median 
scutes are conspicuously sculptured. The sculpture, as shown by the third scutal area, con- 
sists of ten or twelve prominent, sharp, uneven ridges, which radiate forward and outward 
from the middle of the hinder border of the area. Evidently a somewhat similar, but less bold, 
sculpture characterized the areas of the costal scutes; but these surfaces have been injured so 
that it can not be described. There is no evidence of the presence of supramarginal scutes. 

On the left side the costal and marginal plates are broken away. The anterior and 
posterior buttresses of the plastron are thus revealed; and it is evident that the anterior one, 
joining the second costal plate, projected inward a considerable distance, as in Ba'ena, to form 
the anterior boundary of a lateral chamber, whose posterior boundary was formed by the 
hinder buttress joining probably the sixth costal plate. 

When the costal plates broke away, the extremities of the third, fourth, and fifth ribs were 
left adhering in the matrix. These evidently past downward deeply against the inner sides of 
the corresponding marginal plates, as in Chelydra. Such was probably not the condition in 
Ba'ena. The ends of the ribs are terete, not flat as in most other cases. So far as can be deter- 
mined, there were no fontanels between the costal plates and the marginals. 

Of the plastron (plate 7, fig. 5) all is present except the epiplastrals, and possibly the 
anterior part of the entoplastron. The plastron resembles closely that oi Ba'ena; but the hinder 
lobe is not notcht posteriorly, but rounded. There is a considerable fontanel between the inner 
ends of the mesoplastra. This may be due to the immaturity of the specimen; but judging 
from the closeness of all the sutures of our specimen, and from the fact that in Ba'ena the bones 
soon co-ossify, it seems probable that the fontanel would persist till a late period of life. 

The anterior as well as the posterior lobe has a width at the base of 36 mm. The posterior 
has a length of 30 mm., and the anterior was probably about as long. The posterior lobe 
diminishes in width rather rapidly backward. The entoplastron was unusually long and narrow 
in its hinder portion. Nothing can be determined regarding the intergular and gular scutes. 
The mesoplastron is narrowed at the inner end, as in some species of Ba'ena. Each is 
traverst by the pectoro-abdominal sulcus. 

The bridge is 30 mm. wide, fore and aft. The inframarginal scutes which covered the 
bridge can not be mapt with certainty, but there can be little doubt that they were present and 
much like those oi Ba'ena. 

P. sculpta may be regarded as a form ancestral to the later numerous species of Ba'ena 
which have been found in Belly River, Upper Laramie, Puerco, Bridger and Uinta beds. Dr. 
Baur regarded Glyptops plicatulus as the forerunner of Ba'ena (Proc. Acad. Nat. Sci. Phila. 
1891, p. 421); but we now find in the same quarry from which G. plicatulus has been reported 
a form much nearer to Ba'ena than is Glyptops. It becomes evident that we must go back much 
further to find the common ancestor oi Glyptops and Proba'ena. 

Platychelys, of the Upper Jurassic of Solothurn, Switzerland, is closely related to Ba'ena 
and Proba'ena, and has been assigned by Lydekker to the Pleurosternidae. It differs in having 
a more highly sculptured carapace, supramarginal scutes, and mesoplastrals which do not 
reach to the midline. 

Genus BAENA Leidy. 

Shell firmly joined to the carapace by sutural union with the lateral peripherals and by 
broad and high axillary and inguinal buttresses. Hinder border of the carapace scallopt, and 
with an extensive excavation over the tail. Nuchal bone in contact with the first neural; no 
preneural; no supramarginal scutes; anterior lobe of plastron not extended in front of the 
carapace. Mesoplastra large, with the outer ends expanded. Posterior plastral lobe slightly 
emarginated. Intergulars, gulars, and inframarginals present. Skull broad, with the temporal 
region extensively rooft, the squamosals in contact with the parietals. Jugal forming a part of 



6o FOSSIL TURTLES OF NORTH AMERICA. 

the rim of the orbit. Triturating surface of the maxilla furnisht with a prominent longitudinal 
ridge. Choanae opening on a line joining the fronts of the orbits. 

Key to Species of BaI^na. 
//'. Judith River species. 

1. Length of anterior lobe 0.60, its width 0.82, of width of bridge; width of hinder lobe 

0.94 of width of bridge; entoplastron longer than broad callosa 

2. Plastron known only from part of anterior lobe; the entoplastron broader than long . . antiqua 
A^. Laramie species. 

1. Length of anterior lobe 0.92, its width i .00, of width of bridge; width of hinder lobe 

1 . 04 of width of bridge hatchert 

2. Length of anterior lobe o . 58, its length o . 79, of width of bridge; width hinder lobe o , 75 

of width of bridge marshi 

A . Torrejon species escavada 

A*. Bridger species. 

1. Shell broad behind and deeply scallopt; strongly sculptured on back arenosa 

2. Not so strongly sculptured; a broad groove along the back riparia 

3. Shell oval, thin; the sculpture broken up into wrinkles; no median groove sima 

4. Shell oval; rounded behind; nearly smooth clara 

A^. Unita species emilite 

Baena callosa Hay. 

Plate 8, fig. i; teit-figs. 35, 36. 
Baena callosa, Hay, Ann. Carnegie Museum, ill, 1904, p. 178, plate ix, text-figs, i, 2. 

This species is based on an incomplete shell which belongs to the Carnegie Museum, in 
Pittsburg, Pennsylvania. The number is 330. It was collected in the year 1903, by Mr. J. B. 
Hatcher, in the Judith River beds of Willow Creek, Gallatin County, Montana. 

The posterior fourth of the carapace is missing; and of the anterior three-fourths, many of 
the peripherals and portions of the costals are wanting (text-fig. 35). The entire length of the 




Figs. 35 and 36. Baena callosa. Type. X'. 

35. Carapace, c. 5. i, c.s. 2, etc., costal scutes; v.s. i, v.s. 2, etc., vertebral scutes. 

36. Plastron, dfc, abdominal scute; an, anal scute; eM(, entoplastron; f/>/, epiplastron; /em, femoral scute; g, gular 

scute; hum, humeral scute; hyo, hyoplastron; hypo, hypoplastron; ig, intergular scute; mes, mesoplastron; 
pec, pectoral scute; xiph, liphiplastron. 



.16 



BAENID^. 



6i 



shell was about 250 mm.; the width something over 200 mm. The sutures between the various 
bones are not obliterated, but the preservation is such that they can not be satisfactorily traced. 
Most of the anterior border of the nuchal is broken away. The thickness at the free border 
is 6 mm.; and this border was rounded in section. The third costal is much thickened for 
the reception of the axillary buttress of the plastron, and the fifth and sixth were similarly 
thickened for the inguinal buttress. The second costal, near its proximal end, is 5 mm. thick. 

The surface of the carapace presents evidences of a low ridge along the midline. On the 
area of the first costal scute there is a low elongated boss; and just in front of it, near the border 
of the shell, is a smaller one. In a complete shell there would probably be found a lateral 
carina on each side. 

The first vertebral scute is small, having probably a length of less than 30 mm. and a 
width of 60 mm. The second is 48 mm. long and 65 mm. wide; the third, 57 mm. long and 75 
mm. wide. In the original description the figures indicating the widths of the second and the 
third had exchanged places. The fourth was fully as long as the third. The first costal 
scute is small, being about 36 mm. in fore-and-aft extent. 

The plastron lacks the hinder extremity (plate 8, fig. i; text-fig. 36). The total length 
must have been close to 205 mm. The breadth, measured on the mesoplastra and following 
the curves, is 186 mm. The median region is slightly concave as far outward as a ridge which 
joins the free border of the anterior lobe with that of the posterior lobe. From this ridge the 
lower surface slopes upward and outward to the outer borders of the plastral bones. The 
bridge has a fore-and-aft extent of 87 mm. The anterior lobe is short and narrow, the 
length being 52 mm.; the width at the base, 72 mm.; at the hinder ends of the epiplastra, 38 
mm. The latter bones are small, and they meet along the midline, in front of the entoplastron, 
only 5 mm. The entoplastron is relatively large, the length being 28 mm.; the width, 17 mm. 
Seen from the upper surface, this bone is broadly spear-shaped, with an anteriorly directed 
process, a longer one directed backward, and a right and a left process. Its length on this 
upper surface is 33 mm. The free borders of the anterior lobe are rounded in section. The 
thickness of its various bones is about 7 mm. 

On the upper surface of this plastron there is a low ridge passing from one axillary buttress 
to the other, making the thickness of the bone at the midline 9 mm. A similar thickening of the 
bones is found between the inguinal buttresses, the thickness becoming 1 1 mm. 

The mesoplastral sutures are distinct everywhere except near the midline in front of the 
right mesoplastron. The left mesoplastron is 21 mm. wide at the midline and apparently 43 
mm. at the outer end. The mesoplastron of the right side is only 36 mm. wide at the outer end. 

The posterior lobe is 83 mm. wide at the 
base. It is flat below. On the upper surface 
there is a thickening parallel with the free border 
on each side. From the summit of the ridge thus 
formed the surface slopes to the acute border 
and toward the midUne. Just behind the inguinal 
notch the thickness of the bone is 14 mm.; where 
the hypoxiphiplastral suture crosses the midline, 
only 4 mm. thick. 

The sulci are in general distinctly developt. Those behind the intergular are somewhat 
obscure. The intergulars do not separate the gulars. The various scutes meet their fellows 
along the midline as follows: Intergulars, 12 mm.; gulars, 9 mm.; humerals, 32 mm.; 
pectorals, 41 mm. ; abdominals 27 mm.; femorals, 40 mm. The length of the anals is indeter- 
minable. They lie partly on the hypoplastral bones. On each bridge there are 3 inframar- 
ginals, whose outer borders rested on the bridge peripherals. 

The table herewith is intended to present the most obvious differences in the proportions 
of the plastral bones in the three species, B. hatcheri, B. marshi, and B. callosa. The width of 
the bridge is taken as the unit. 

It is seen that B. hatcheri has, relatively to the width of the bridge, large anterior and 
posterior lobes; that B. marshi has both lobes small; and that B. callosa has the anterior 
lobe short and of moderate width, while the hinder lobe is broad at the base. 



Dimensions. 


Baena 
hatcheri. 


Baena 
marshi. 


Baena 
callosa. 


Width of bridge 

Length of anterior lobe 
Width of anterior lobe . 
Width of hinder lobe. . 


1. 00 

.91 

1.00 

1.04 


1.00 

.58 
•79 
•75 


I/X> 

.60 
.82 
•94 



62 



FOSSIL TURTLES OF NORTH AMERICA. 



The anterior lobe of the present species is narrower and more pointed than that described 
by Lambe (Cent. Canad. Palaeont., iii, 1902, p. 44, figs. 10, a, b) under the name B. antiqua. 

Baena antiqua Lambe. 

Text-figs. 37, 38. 

Baena antiqua, Lambe, Contrib. Canad. Palasont., fll, 1902, p. 44, figs. 10, a, b. 

The materials on which this species was based belong to the Canadian Geological Survey. 
They were collected in 1901, in the Judith River beds, on Red Deer River, British America, by 

Mr. L. M. Lambe, of the Canadian Survey. The type of the species 
consists of the median region of the anterior two-thirds of the cara- 
pace. Near it was found the greater part of the anterior lobe of 
the plastron, and this is believed to belong to the same individual. 
The front of the carapace (fig. 37) was apparently broad 
and rounded. The nuchal bone is 28 mm. fore and aft; 58 
mm. from side to side. The neurals are irregular in form and 
outlines. The vertebral scutes are broader than long. The 
dimensions of the three present are given in the accompanying table. 

No supernumerary costal appears on each side of the first vertebral, such as is found in 
many species of the genus. 

The fragment of plastron (fig. 38) presents an entoplastron that differs from all others at 
present known in being lozenge-shaped and broader than long. Its length is 22 mm.; its 
breadth, 28 mm. 



■ VertebraL 


Length. 


Width. 


I 


40 


73 


z 


62 


70 


3 


66 


75 




Fig. 37. — Baena antiqua. Carapace. Type. X§. Reduced from Lambe's original drawing. 

bones; n. i, etc., neural bones; nu. p. nuchal bone. 
Fig. 38. — Baena antiqua. Anterior lobe of plastron. XJ. From drawing by Lambe. 
Fig. 39. — Baena marshi. Plastron of type. X/o- 



etc., costal 



Baena marshi. Hay, Amer. Jour. Sci. 



Baena marshi Hay. 
Plate 8, fig. 2; text-fig. 39. 
xviii, 1904, p. 261, plate xi, text-fig. i. 



The type and only known specimen of this species comes from the Laramie deposits of 
Wyoming. It was collected in 1889, by Professor J. B. Hatcher, in Converse County, between 
Buck and Lance Creeks, and is now in the Yale University Museum. 

The specimen is considerably damaged. There are present the cast of the greater portion 
of the interior of the shell, the greater part of the central portion of the carapace and most of the 



BAENID^. 



63 



Dimensions. 


Baina 
marshi. 


Baena 
hatcheri. 


Length of plastron 

Width of the bridge 

Length of anterior lobe . . 
Width of anterior lobe. . . 
Length of hinder lobe . . . 
Width of hinder lobe 


260 ± 
110 

70 

65 ± 
90 


305 
"5 
106 

"i ! 
98 

IXO 



left side, and a large part of the plastron. The length of the carapace is conjectural, but it 
appears to have been at least 300 mm. The width was 220 mm. Its composition can not be 
determined, since the bones have co-ossified and obliterated the sutures. In the median region 
the bones reach a thickness of from 10 to 13 mm. The outer surface is smooth. The sulci are 
narrow and shallow, and in most places are not traceable. The second, third, and fourth 
vertebral scutes varied from 65 to 70 mm. in width. The first and fifth were probably somewhat 
wider. 

The hinder extremity of the plastron (plate 8, fig. 2; text-fig. 39) is missing, so that its 
form can not be determined. The anterior lobe has the right border nearly complete to 

beyond the midline in front, so that its form is known. 
The dimensions of the plastron are shown in the 
accompanying table. In order that the distinctness of 
the species from B. hatcheri may be seen, the dimensions 
of the latter are added. 

The plastron is somewhat concave. The concavity 
extends laterally to a rounded ridge which runs from the 
outer border of the anterior lobe to the outer border 
of the posterior lobe. From this ridge the outer ends 
of the hyoplastron and hypoplastron extend upward 
and outward to the peripherals, and the elevation is 
continued on the latter to the carina which unites the free borders of the third and the seventh 
peripherals. From the midline of the plastron to the ridge is 55 mm.; from the ridge to the 
lateral carina is about 85 mm., the measurements being taken on the mesoplastron. 

Most of the sutures of the plastron may be traced. The limits of the entoplastron are 
not determinable; nor have the sutures between the xiphiplastra and the hypoplastra been 
observed. The mesoplastra meet along the midline for about 23 mm. while their outer ends are 
65 mm. wide. The sutures between the plastral bones and the bridge peripherals are distinctly 
shown. The whole width of the plastron, on the mesoplastra, and following the curves, is 
215 mm. 

The gular scutes appear to have met for some distance along the midline. The gulo- 
humeral sulcus runs nearly directly across the lobe and meets the median line 27 mm. behind 
the anterior border. The following are the antero-posterior dimensions of the various plastral 
scutes, measured along the midline: Intergulars, 17 mm.; gulars, 10 mm.; humerals, 46 mm.; 
pectorals, 50 mm.; abdominals, 47 mm.; femorals, 53 mm.; anals, 45 mm. On the bridge 
there are 4 inframarginals, of which the inguinal is the largest, and the axillary somewhat the 
smallest. The outer borders of these overlap on the bridge peripherals. 

This species appears to differ from Baena hatcheri in the smaller plastron, the longer 
bridge, and the greater thickness of the bones of the carapace, especially of the dorsal region. 
It is named in honor of Professor O. C. Marsh, formerly professor of vertebrate paleontology 
in Yale University. 

Baena hatcheri Hay. 

Plates 9, 10; text-6gs. 40, 41. 

Baena hatcheri, Hay, Ann. Carnegie Museum, i, 1901, p. 325, plate xv. — Hatcher, Bull. U. S. Geol. 
Surv. No. 257, p. 79. 

The type of the species is a very complete shell which was collected by Mr. J. B. Hatcher, 
in the year 1900, in the Ceratops beds of the Laramie formation, in Converse County, 
Wyoming. The locality given more particularly is a sandstone bluff on the south side of 
Lance Creek, opposite the mouth of Dolgie Creek. The specimen belongs to the collection 
of the Carnegie Museum. 

The whole plastron is present and all of the carapace except a small portion of the rear. 
The sides of the carapace are somewhat crusht in, and some crushing has been suffered by the 
bridge peripherals; but these defects do not stand in the way of determining the characters of 
the species. It displays all the epidermal sulci and nearly all of the bone sutures. Moreover, 
the matrix, a soft sandstone, has been removed, so that the interior too can be observed. 



64 



FOSSIL TURTLES OF NORTH AMERICA. 



The total length of the carapace (plate 9) was originally 368 mm.; the total breadth, 
280 mm.; the height from the bottom of the plastron, about 145 mm. The greatest breadth 
of the carapace was somewhat behind the inguinal notches. From here the border rounds 
rapidly to the median excavation behind. The anterior end is rather pointed. In front, the 
margin of the carapace is unbroken by serrations or sinuses, except that the nuchal is slightly 
excavated. The hinder portion, from the inguinal notches backward, is scallopt as in the 
other species of the genus. It is also thin and rather acute. Even at the bridges the border was 
narrowly rounded. 





Fig. 40. — Ba'ena hatcheri. Type. 
Xj. Carapace. 



Fig. 41. — Ba'ena hatcheri. Type 
Xj. Plastron. 



The sutures between the bones are fine and their course is often indicated by only the 
finely striated border of the adjoining bone. 

The nuchal bone is nearly quadrate in form. It is 43 mm. long fore and aft, with a width 
ot 59 mm. in front and a maximum width of 72 mm. The neurals in general are hexagonal, 
with the broader end forward. The table annext presents the dimensions of the neurals. 

The single suprapygal had a length of 50 mm. and a width of 56 mm. No true pygal is 
interposed between the peripherals of the last pair. 

The costal plates vary considerably in the fore-and-aft extent. Measured at their proximal* 
ends they have the following widths : First, 48 mm.; second, 40 
mm.; third, 47 mm.; fourth, 33 mm.; fifth, 47 mm.; sixth, 32 mm.; 
seventh, 32 mm.; eighth, 31 mm. The fifth costal presents the 
peculiarity of being very narrow at the distal end — only 9 mm. 
The peripherals are high, the first two about 38 mm.; the 
third, 33 mm.; the next three, about 52 mm.; the seventh, eighth, 
ninth, about 68 mm.; the tenth, eleventh, and twelfth, about 
48 mm. The sutures between the peripherals behind the eighth 
are not visible, but they were probably not far removed from the 
lines representing them. 

The epidermal scutes are all defined by sulci which are 



NeuraL 


Length. 


Width. 


I 


40 


40 


2 


36 


30 


3 


5' 


36 


4 


3S 


33 


5 


47 


33 


6 


36 


3^ 


7 


3^ 


28 


8 


^3 


3° , 



BAENID^. 



65 



distinct, but very narrow and shallow. The vertebrals are relatively wider than they are in any 
of the other species of the genus. From the first vertebral there is cut off on each side an acces- 
sory lateral scute, and this has much reduced its size; also, from its anterior end there is cut off 
a small supernumerary vertebral, so that there are really 6 vertebrals, as in Chisternon. The 
table herewith gives the dimensions of the vertebrals. The width of the central ones is really 
somewhat greater than the figures indicate, on account of some lateral compression. 

The triangular supernumerary lateral scutes are each 39 mm. fore and aft, and 50 mm. 
from side to side. 

The area usually occupied in turtles by the nuchal scute is broken up into 4 scutellae 
unsymmetrical in form and size. Of these the extreme right and left are larger and much 
alike in form and size; the median two are much unlike, one being very small. 

Behind the nuchal scutellae there are 13 marginals on each side. Usually the costo-marginal 
sulci run along some distance below the costo-peripheral sutures. The first marginal extends 
back from the border of the shell only 16 mm.; the fourth, 40 mm.; the sixth, 55 mm., and 
rises above the costo-peripheral suture; the eighth, 53 mm.; the eleventh, 41 mm. The thir- 
teenth is considerably smaller than the twelfth. As in other species of Baena, there was no 
supracaudal scute. 

The plastron (plate 10) is rather narrow, especially the hinder lobe. Its total length is 
305 mm. The bridge has a width, fore and aft, of 1 15 mm.; a length, from the inner end to the 
border of the carapace, of 95 mm. It rises considerably from the inner end to the outer. The 
anterior lobe is 106 mm. long; 1 15 mm. wide at the base. The width diminishes gradually to 
the gulo-humeral sulcus, then rapidly to the midline in front. The thickness of the border of 
the lobe is about 8 mm.; behind the entoplastron, about 6 mm. 

The hinder lobe is 98 mm. long; 120 mm. wide at the base. The lateral borders are 
nearly straight and convergent to the ends of the femoro-anal 
sulcus. Here the width is 71 mm. Behind this, the sides are 
nearly parallel for a short distance; then they round rapidly to 
the shallow hinder excavation.. Just behind the inguinal notch 
the thickness is 18 mm.; near the hinder extremity, only 7 mm. 
The entoplastron is oval, 47 mm. long and 36 mm. wide. 
The hyoplastrals extend along the midline 85 mm., and each 
reaches laterally, behind the axillary notch, 105 mm. There are 
large mesoplastrals. The median ends are 24 mm. wide, the 
lateral ends, 61 mm. Each extends outward from the midline 
125 mm. The hypoplastrals join along the midline for the distance of 75 mm.; the xiphi- 
plastrals, 60 mm. 

The intergulars and gulars are of about the same form and size, all starting from a point 
near the front of the entoplastron. The humerals are 63 mm. long and meet for some distance 
behind the entoplastron. The pectorals occupy about 54 mm. of the midline; the abdominals, 
about 48 mm.; the femorals, about 78 mm.; the anals, 37 mm. 

On the bridge of each side are seen 4 large inframarginals. These lie principally on the 
plastral bones, but partly on the peripherals. 

The hyoplastra and hypoplastra send upward strong buttresses against the inner surfaces 
of the first, and of the fifth and sixth costals respectively; but these buttresses, especially the 
inguinal, do not extend inward so far as they do in the other species of the genus. The axillary 
buttress is directed upward and forward toward the front of the first dorsal vertebra. Its 
inner border is acute. At its upper end the buttress joins the first rib, which is wide and fur- 
nisht with a sharp border; thus the partition bounding the sternal chamber anteriorly is 
carried up to the first dorsal vertebra. The inguinal buttress, seen from behind, appears to be 
about 30 mm. wide; but in front of it the sternal chamber extends far out toward the border of 
the carapace. 

Baena escavada sp. nov. 
Plate II, figs. I, 2; text-figs. 42, 43, 

The chelonite on which this species is based was obtained by Dr. J. L. Wortman and Mr. 
Walter Granger in 1896, in the Torrejon deposits, at the head of Escavada Creek, in New 

5 



Vertebral. 


Length. 


Width. 


, 


>9 


3* 


z 


50 


83 


3 


75 


90 


4 


80 


90 


5 


90 


'' 


6 


" 


88 



66 



FOSSIL TURTLES OF NORTH AMERICA. 



Mexico. The specimen is not quite complete, being somewhat crusht and fractured and 
having a portion of the margin of the left side missing. 

The species closely resembles the others of the genus, but possesses sufficiently distinctive 
characters. The specific name is that of the stream near which the specimen was found. The 
catalog number is 1203, of the American Museum of Natural History. 

All traces of the sutures between the bony elements of the shell are obliterated thru co- 
ossification. The sutures between the epidermal scutes are distinct, but narrow and only 
moderately imprest. The total length of the carapace (plate 1 1, fig. i ; text-fig. 42) is 381 mm. 
In the midline the length is about 12 mm. less, on account of the slight emargination in front 
and the excavation in the rear. The breadth was close to 300 mm. The carapace is broad, 
ovate, obtusely pointed in front, truncate behind. On each side of the anterior emargination 
the border was gently repand. The hinder border, on each side of the excavation for the tail, 
was scallopt. On the hindermost part of the carapace there is a moderate rounded keel. From 
this there may be traced forward faint indications of the two parallel grooves so distinct in 
B. arenosa. Except these grooves, the ornamentation seen in the latter species is absent. 





43- 



Figs. 42 and 43. — Ba'ena escavada. Type. xj. Form of shell and the scute areas. 



42. Carapace. 



43. Plastron. 



The most distinctive character of this species is seen in its narrow and spatulate anterior 
plastral lobe (plate 11, fig. 2; text-fig. 43). The plastron as a whole is relatively small. The 
total length is 295 mm. The anterior lobe has a length of 83 mm. and a breadth, at its base, of 
96 mm. From the base the lateral borders run forward and inward to within 30 mm. of the 
front, at the ends of the sutures between the gular and humeral scutes. Here the width is 61 
mm. Beyond these points the lobe expands again to 64 mm.; then curves forward and inward 
to the ends of the intergular sutures. The extreme end of the lobe is truncated and falls about 
30 mm. short of the anterior border of the carapace. 

The posterior lobe has a width of 114 mm. at the base and a length of 75 mm., failing to 
reach the excavation in the carapace by about 47 mm. It narrows, as it passes backward, more 
rapidly than does that of B. arenosa. The hinder border is slightly concave. 

The bridge has a width of 135 mm. Its length, to outer margin of the shell, is 105 mm. 



BAENID^. 67 

The vertebral scutes are relatively narrow, the second having a length of 88 mm. and a width 
of 65 mm.; the third a length of 85 mm. and a width of about 70 mm.; the fourth a length of 
80 mm. and a width of 70 mm.; the fifth a length of 48 mm. and a width of 80 mm. In the 
case of the first vertebral the same lack of symmetry is to be seen as has been observed in so 
many other specimens belonging to the genus Ba'ena. 

The costo-marginal sulci are distant from the edge of the carapace about 22 mm. Those 
subdividing this anterior marginal region are too obscure for certain determination. There 
are indications of one which crost this region about 15 mm. to the left of the midline. There 
was, therefore, probably a nuchal scute 30 mm. long from side to side. Beyond this the 
marginals increase in length and breadth. Over the bridge they rise on the sides of the 
carapace 45 mm. 

On the plastron are distinct gulars and intergulars. The humero-pectoral sulcus crosses the 
midline on the line joining the axillary notches. Laterally the sulcus is suddenly turned forward 
and outward. The pectoral scutes meet along the midline for a distance of 53 mm., and extend 
laterally about 72 mm. The abdominal scutes occupy 52 mm. of the midline; the femorals 67 
mm.; the anals 50 mm. As in other species of Ba'ena, the suture between the femorals and the 
anals runs outward, then turns backward for some distance, then again outward. 

There are 4 large inframarginals. 

Baena arenosa Leidy. 
Plate 12; plate 13, fig. i; plate 14, figs. 1-3; teit-figs. 44-51. 

Baena arenosa, Leidy, Proc. Acad. Nat. Sci. Phila. 1870, p. 123; U. S. Gaol. Surv. Wyoming, etc., 
1870 (1871), p. 367; U. S. Gaol. Surv. Montana, ate, 1871 (1872), p. 368; Contrib. Ext. Vart. 
Fauna W. Tarrs., 1873, pp. 161, 343, pi. xiii, figs. 1-3; .'pi. xv, figs. 1-5; pi. xvi, figs. 8, 9. — Cope, 
.'Append. LL of Ann. Report Chief of Engineers, 1875, p. 96; .'Wheeler's Surv. looth Merid., 
'877. P- 52, pl- xxiv, fig. 32. — Baur, Proc. Acad. Nat. Sci. Phila. 1891, p. 426, fig. — Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 437. 

Baena afflnis, Leidy, Ann. Report U. S. Gaol. Surv. Wyoming, etc., 1870 (1871), p. 367. 

Baena arenosa, the type of the genus Baena, was based on a shell lacking only the anterior 
lobe of the plastron and the anterior border of the carapace. This specimen is now in the 
United States National Museum at Washington. It was figured and described at length in Dr. 
Leidy's work of 1873. The specimen was obtained in the Bridger deposits, at the junction of 
the Big Sandy and Green Rivers, in southwestern Wyoming. These beds are regarded as 
belonging to the lowermost of the Bridger formation. 

The specimen described by Leidy evidently had originally a length of close to 340 mm. and 
a width of 288 mm. The rear of the carapace is broadly rounded. The vertebral scutes are 
broader than long. The hinder lobe of the plastron is broad and it narrows slowly backward. 
The width of the anterior lobe, taken from the outer ends of the humero-pectoral sulci, equals 
half the length of the plastron behind this. Dr. Leidy states that the position of the former 
sutures can not be detected. This is true as regards the outer surface of the bones; but on the 
upper side of the plastron the sutures on each side of the mesoplastrals are to be observed. 
The left mesoplastron had a width of about 25 mm. at the midline; that on the right side was 
narrower. 

A portion of the pelvis and the sacral vertebrae and ribs of this specimen were figured by 
Dr. Leidy. Later, Dr. Baur obtained from the matrix of the specimen additional parts of the 
pelvis and briefly described them. While some parts are still wanting there is enough to show 
that the ischia were united with the pubes along the midline and that the pubes extended at 
least 35 mm. in front of their hinder border at the midline (figs. 44, 45). The upper end of 
the ilium was expanded backward. The width of this expanded part was equal to the height, 
35 mm. 

The writer follows Dr. Leidy and Professor Cope in identifying the former's B. afpnis as 
the earlier described B. arenosa. The original description of 5. affinis was exceedingly brief and 
hesitating. It was supposed to be distinct from B. arenosa because of the presence of only 
3 inframarginals. In Leidy's next reference to the species, he referred it to his earlier B. 
arenosa. The type is now in the collection of the Philadelphia Academy. It was 



68 



FOSSIL TURTLES OF NORTH AMERICA. 



obtained at Church Buttes, in the level known as B. Dr. Leidy's figure makes the anterior 
lobe of the plastron appear too short and too narrow. The plastron has a total length of 275 
mm. The anterior lobe is 75 mm. long and 70 mm. wide at the base. The bridge has a width 
of 123 mm. The hinder lobe is "JJ mm. long and 1 10 mm. wide at the base. The carapace has 
a length of 300 mm. in a straight line. The surface is uneven, especially within the areas of the 

vertebral scutes. There appear to have been no supernumer- 
ary costal scutes. The dimensions of the vertebrals are given 
in the accompanying table. 

The American Museum expedition of 1903 collected a 
number of specimens which must be referred to this species. 
The most important of these is No. 5973, collected at Grizzly 
Buttes, Wyoming. It furnishes a somewhat damaged shell; 
the skull, lacking the left side and the lower jaw; a portion of 
the shoulder-girdle; the humerus, lacking the distal end; and 
the ulna. The length of the carapace (plate 12) in a straight 
line is 330 mm., to the bottom of the posterior notch, 320 mm.; 
its width, about 315 mm. The bones are thoroly co-ossified 
and the sutures obliterated. The anterior border projects somewhat at the midline. The pos- 
terior border is broad, with a median excavation 60 mm. wide and lateral scallops. 

48. 



Verte- 
bral. 


Type of B. 
affinis. 


No. 5973 
A. M. N. H. 


Length. Width. 


Length. Width. 


2 
3 

4 
5 


50 72 
73 (" 
73 ' 64 
60 b3 

55 , 75 


48 60 

72 67 
77 ' 74 
62 69 

57 77 



46. 




44- 



47- 



Figs. 44-48. — Baena arenosa. No. 5973 A. M. N. H. 



44. Pelvis seen from left side. XS. 

45. Left half of pelvis seen from below. 

46. Plastron. Xj. 



x«. 



47. Left humerus. X§. 

48. Right ulna. XS- 



On each side of the first vertebral there is a small supernumerary costal scute. Along the 
midline there is a narrow ridge and within the areas of the vertebral scutes a number of sym- 
metrically arranged ridges. The dimensions of the vertebrals are given in the table above. 

The plastron (plate 13, fig. i; text-fig. 46) is 287 mm. long. The anterior lobe is ■/'/ mm. 
long; 104 mm. wide at the base; and jy mm. at the gulo-humeral sulcus. The limits of the 
entoplastron can not be traced. The bridge is 125 mm. wide. By means of the striations on the 



BAENID^. 69 

bones the limits of the mesoplastrals can be pretty well determined. They appear to have 
joined each other at the midline for a distance of about 25 mm. The hinder lobe is 84 mm. 
long; 114 mm. wide at the base; and 92 mm. wide at the gulo-humeral sulcus. At the rear 
there is a broad and shallow notch. The plastral scutes offer no especial deviations from the 
normal. Their forms and dimensions may be determined from the figure. On each of the 
bridges there are 3 inframarginals. 

The right humerus (fig. 47) lacks the distal end. Its length has been approximately 70 mm. 
The resemblance to that oiChelydra is close. The head is, however, not so large, and especially 
it is comprest in a plane perpendicular to the dorsal surface of the bone. Furthermore, the 
plane of this comprest head inclines to the radial side of the humerus; whereas, in Chelydra, 
it falls far outside of the ulnar side. The ulnar and radial processes are large and the distance 
from the outside of one to the outside of the other measures 32 mm. In the case of the humerus 
of the type of B. rtparia this distance is only 26 mm. In B. arenosa, as well as B. riparia, the 
planes of the two processes are at right angles with each other, as in Chelydra. The processes 
are much thicker than in Chelydra. The shaft has a diameter of 8.25 mm. The groove 
leading to the ectepicondylar foramen is broad and deep. A fragment from near the distal end 
of the left humerus has a width of 21.5 mm. The right ulna (fig. 48) is present. The shaft is 
not flattened like that of the Cryptodira, but is nearly cylindrical, like that of Hydromedusa. 
The articulation for the humerus is, however, like that of the Cryptodira. The bone is 52 mm. 
long; 15 mm. wide at the distal end. 

Plate 14, figs. 1-3, represents what is left of the skull. The occipital condyle and the 
premaxillae are wanting, but the length between these two was close to 60 mm. The greatest 
width (plate 14, fig. i) just in front of the tympanic cavities was 62 mm. From the tips of the 
nasals to the extremity of the supraoccipital is 57 mm. All the sutures of the roof of the skull 
are obliterated. The tympanic cavity (plate 14, fig. 2) has a horizontal diameter of 15 mm. and 
a vertical of 18 mm. The stapedial rod remains in its natural position. The eyes appear to 
have lookt upward and outward more than in Chisternnn hebratcum (fig. 78, p. 89), and were 
smaller. The orbits are circular with a diameter of 16 mm. The interorbital space is 22 mm.; 
the nasal opening, 20 mm. wide; the maxilla, below the eye, 10 mm. wide. Seen from below 
(plate 14, fig. 3), the cutting-edge of the maxilla is sharp, thickened upward to 5 mm., and at 
least 30 mm. long. There is a prominent ridge on the triturating surface of the maxilla, highest 
on each side of the choanje. The least width across the pterygoids is 13 mm. From the outer 
posterior angle of the basioccipital bone a strong ridge runs forward toward the basisphenoid. 
The basisphenoid did not come into contact with the vomer. Unfortunately, the lower jaw is 
missing. 

On the upper side of the skull are seen numerous anastomosing grooves, the boundaries of 
horny scutes that covered most of the upper surface. Some of these are represented in fig. i , 
plate 14. 

The skull differs from that of Chisternon hebratcum in having a wider interorbital space, 
a smaller eye, and far more prominent masticatory ridges on the upper jaws. It is most like 
that o{ B. riparia. Unfortunately, both skulls are damaged, so that full comparison is not pos- 
sible. The two skulls are of almost exactly the same size. The snout of 5. arcnoj-a was broader, 
as was also the interorbital space. The eye of 5. riparia appears to have had a greater vertical 
diameter, but of this we can not be certain at present. In B. rtparia the maxilla below the orbit 
is only 9 mm. wide. In B. riparia the ridge along the junction of the basisphenoid and the 
pterygoid is far less prominent. In this species, too, there is a low ridge running from the pedicel 
of the quadrate to meet the free border of the pterygoid. Another, starting from the same 
point, runs forward and upward along the suture between the quadrate and the pterygoid. 
The surface of the bone between these two ridges is somewhat scoopt out. In B. arenosa the 
ridges are little developt and the space between them is convex. 

No. 1 1 15 of the American Museum is identified as belonging to the present species. It 
was collected by the museum's expedition of 1893 into southwestern Wyoming. The locality 
whence it was obtained is Laclede Meadows, southwest of Bitter Creek station and west of 
Haystack Mountain. The deposits belong to the Washakie formation. Of this individual the 
front and a part of the right border of the carapace (fig. 49) and the front of the anterior lobe 
of the plastron (fig. 50) are missing. The remainder of the shell is well preserved. It had origi- 



7° 



FOSSIL TURTLES OF NORTH AMKRICA. 



nally a length of" about 395 mm., measured in a direct line. The greatest width, 340 mm., is 
across the middle of the length of the carapace. Across the axillary notches the width is 315 
mm., and that taken 25 mm. in front of the hinder extremity of the plastron is 306 mm. It will 
be seen therefore that the extremities of the shell are broad. The height of the shell is now 145 
mm. but it was doubtless greater during life. 





Figs. 49 and 50. — Baena arenosa. Xj. No. 11 15 A. M. N. H. 

49. Carapace. Shows the scute areas. Front injured. 

50. Plastron. Shows many of the bones and the scute areas. Front restored. 

The hinder border of the carapace (fig. 49) is rather thin and acute, scallopt as in the 
other species of the genus, and flared somewhat upward. The anterior border is obtuse. All 

the bones are thoroly co-ossified, so that the forms of the neurals 
can not be determined. The surface is uneven, and especially 
in the areas occupied by the vertebral scutes there are various 
longitudinal, transverse, and oblique ridges. A slight depression 
occupies the midline of vertebrals 3 and 4. The accompanying 
table gives the dimensions of the vertebral scutes. In general, 
they are wider than long. 

As is not infrequent in the species of the genus, there are, on 
the left side at least, 5 costal plates. The most anterior is cut 
from the front of the one usually called the first; altho the most anterior vertebral is reduced 
somewhat in width thereby. The portion of the rim of the carapace between the outer border 
of the small anterior costal scute and the posterior vertebral is occupied by 12 marginal scutes. 
The plastron (fig. 50) has an even, but granulated, surface. The anterior lobe is 133 
mm. wide at the base. The bridges are 155 mm. wide. The limits of the mesoplastra are 
indistinctly discernible. They were about 20 mm. wide at the midline and expanded distally 
to about 90 mm. The hinder lobe is 141 mm. wide at the base and 105 mm. long. It dimin- 
ishes in width slowly backward and the end is truncated. At the ends of the femoro-anal sulci 
the width is yet 113 mm. The lobe lacks about 60 mm. of reaching backward to the hinder 
border of the carapace. 



Vertebral. 


Length. 


Width. \ 


I 




73 


2 


96 


9' 


. 3 


90 


9S 


4 


80 


9° 


S 


75 


100 



BAENID^. 



71 



On the left'bridge there are four inframarginal scutes. Of these the second is the smallest, 
the first and the fourth the largest. All the plastral, as well as the carapacial scutes, agree 
closely with those of Leidy's type. 

A portion of the pelvis is preserved (fig. 51). So far as can be determined, it agrees well 
with that of the type of the species. Unfortunately, the upper end of the ilium is missing. 

Professor Cope figured and described what he regarded as a specimen of B. arenosa (Vert. 
Tert. Form. West, p. 148, plate xvii, figs. I, 2). The specimen is in the American Museum and 
has the number 1 1 1 2. The present writer regards it as belonging to B. riparta. 

Professor Cope has described and figured also a portion of a carapace found by him in the 

Wasatch beds of New Mexico. As the type of B. arenosa 
was discovered in the lowermost beds of the Bridger, it is 
not impossible that the species may occur in the Wasatch; 
but the identification based on a part of the shell is not 
to be depended upon. 

However, the American Museum expedition of 1906 
into the Wasatch deposits of Wyoming secured a specimen 
oi Baena which is referred to this species. This was found 
near Knight's Station, not far from Evanston. The level 
was about 200 feet above Bear River. The catalog number 
of the specimen is 6041. About one-third of the carapace 
in front has been eroded away, but otherwise the shell is 
in fair condition. The length of the carapace was origi- 
nally about 240 mm. The width at the middle of the length 
is 222 mm., and this width is fully maintained to opposite the ends of the femoro-anal sulci. 
So far as can be determined this specimen differs from most Bridger specimens in the greater 
smoothness of the areas of the vertebral scutes; but this appears to have been nearly the 
condition of Leidy's type. Cope's specimen obtained in the Wasatch of New Mexico and 
referred by him to the present species had the back sculptured as in most Bridger specimens. 
It appears best, until more is known about the Wasatch form, to identify it as B. arenosa. 




Fig. 51. — Ba'ena arenosa. X§. 
Pelvis seen from below. 



Baena sima sp. nov. 
Plate 13, figs. 2, 3; plate 14, figs. 4-6; plate 15; teit-figs. 52-56. 

The present species has for its type No. 5971 of the American Museum of Natural History. 

This specimen was collected by that museum's expedition of 1903 into the Bridger beds. The 

locality is on Little Dry Creek, south of Fort Bridger, and the level is that designated as B. The 

specimen furnishes nearly the whole of the shell, the skull, with the lower jaw, a number of 

vertebrae, and portions of the limb bones. 

The bones of the shell are so thoroly co-ossified that few of the sutures can be made 

out. The carapace (fig. 52) has an axial length of 360 mm,; the width was close to 260 mm. 

It was apparently rather elevated. There is no depression along the midline. In outline the 

carapace was pointed in front and somewhat contracted behind. 
Posteriorly there is in the border, over the tail, a rather deep 
excavation 72 mm. wide. The posterior peripherals are flared 
upward. The surface of the carapace is very uneven, being 
everywhere covered with coarse pustular elevations; just outside 
of the third and fourth vertebral scutes there are some longitu- 
dinal wrinklings. About 25 mm. outside of these vertebrals there 
are seen on each side distinct traces of a lateral carina. The 

median symmetrically arranged folds and grooves seen in B. arenosa are here quite indistinct. 
The nuchal scute has a fore-and-aft width of 16 mm. and a transverse extent of about 40 mm. 

The first vertebral is 51 mm. long and 80 mm. wide; but there appears to be on the left side 

a small supernumerary costal scute cut out of its normal area. The other scutes have the areas 

given in the table. 

Outside of the nuchal scute there is, on each side, a minute triangular marginal scute. 

The next one, the second, is 21 mm. long on the free border and 21 mm. high. The third is 



Vertebral. 


Length. 


Width. 


2 


76 


68 


3 


gi 


69 


4 


79 


82 


5 


58 


83 



72 



FOSSIL TURTLES OF NORTH AMERICA. 



38 mm. long and 15 mm. high. The seventh, lying below the hinder half of the second costal, is 
56 mm. long and it rises about 36 mm. above the free border of the shell. On account of the 
obtuse border over the bridge the elevation of the lateral scutes is difficult to estimate. 

The plastron (fig. 53) is 320 mm. long. The anterior lobe is 92 mm. long, 112 mm. wide 
at the base, and 80 mm. wide at the gulo-humeral sulci. The bridge has a width of 138 mm., 60 
per cent, of the length of that part of the plastron behind the axillary notches. The hinder lobe 
is 92 mm. long, 127 mm. wide at the base, and 92 mm. at the ends of the femoro-anal sulci. 
The hinder border is slightly excavated. 

The mesoplastra are solidly co-ossified with the contiguous bones, but some traces are 
found of the sutures. The bones appear to have been about 15 mm. wide at the midline. 

The forms of the various plastral scutes are shown in the figure. The course of the median 
sulcus is very tortuous and there are some irregularities in the others. The axillary region is 
damaged on both sides, but appearances indicate that there were 3 left inframarginals, the 





Figs. 52 AND 53. — Ba'ena sima. Type. xj. Showing the form of carapace 
and plastron and the scute areas. 

52. Carapace. 53. Plastron. 

pectoral scute apparently having extended out to the marginals. There is a large inguinal 
inframarginal and another in front of it. There was doubtless an axillary scute, but the bones 
are missing which supported it. On the right side there were 4 inframarginals. 

The skull of this species (plate 13, figs, i, 2; plate 14, fig. 4) is remarkable for its breadth 
and shortness. The premaxillary region is missing and likewise the condyle of the basioc- 
cipital; but the length from one to the other was very close to 64 mm. The breadth across the 
quadrates is 71 mm. From the quadrates the outline of the skull contracts rapidly to below 
the front of the orbits, where there is a sudden constriction. From this the outline contracts 
slowly, then rounds into the broad snout. The upper surface is convex. All the bones are 
solidly co-ossified, and no sutures are to be traced. 

The temporal fossx are rooft over extensively, so that between the end of the short 
supraoccipital and the postero-lateral angles there is on each side only a shallow sinus. The 
interorbital space is 26 mm. wide. The orbits have their greatest diameter, 17 mm. directed per- 



BAENID^. ']T, 

pendicularly, while the horizontal diameter is only 14 mm. The narial opening is 21 mm. wide 
and it looks strongly upward as well as forward. The bones roofing it are 6 mm. thick. The 
tympanic region is damaged, but the vertical diameter was 20 mm. The quadrate is deeply 
notcht for the passage of the stapedial rod. 

At their narrowest part the pterygoids are 14 mm. wide. There are large postpalatine 
foramina. The front of the choanae is placed 17 mm. behind the premaxillae. The cutting- 
edges of the maxillae converge at nearly right angles. The triturating surface is 7 mm. wide. 
At its inner border, on each side of the choanae, arises a sharp crest. These crests converge to 
the front of the choanae, then run parallel to near the premaxillae, thus producing a deep 
groove in front of the choanx. 

The lower jaw (plate 14, figs. 5, 6) is thick and heavy. From the middle of a line joining 
the front borders of the articulation for the quadrates to the tip of the jaw is 40 mm. This line 
prolonged backward even with the extremities of the rami would measure about 52 mm. while 
the greatest width was 60 mm. The triturating surfaces are concave transversely, and are 7 
mm. wide. The middle of each ramus is 9 mm. thick and 15 mm. high. The tip of the jaw is 
turned upward, beak-like. The length of the symphysis on the lower side is 21 mm. 

The upper surface of the skull was undoubtedly covered with numerous horny scutes. 
These are shown, as far as determined, in plate 13, fig. i. They are somewhat irregular in 
form and disposition, but there is no difficulty in making out some symmetry in their arrange- 
ment. The horny covering of the maxillae appears to have been divided, for a deep sulcus runs 
downward from the front of the orbit to the cutting-edge. 



Figs. 54-56. — Bdena sima. No. 5907 A. M. N. H. 
54. Pelvis, right side. Xj. 56. Digit. Xi- SS- D'stal end of humerus. Xi. 

Accompanying the shell of this specimen are various portions of the internal skeleton, 
mostly fragmentary, however. The left humerus is represented by the proximal and the distal 
ends. The proximal shows a width, from the outside of the ulnar to the outside of the radial 
process, of 33 mm., a single millimeter more than in the specimen of B. arenosa, No. 5973? 
above described. Nevertheless, the long diameter of the head is 14.5 mm.; that of No. 5973, 
13 mm. The ulnar process has a thickness of 11 mm.; that of No. 5973 a thickness of 9 mm. 
The distal end of this bone is 27 mm. wide. The trochlea has a narrow rounded ridge for the 
head of the radius and a broader one for the head of the ulna, the two being separated by a 
groove. Above the trochlea is a deep olecranon depression. The prepubic process resembles 
that represented in fig. 86, but it is thin and flat. With this specimen are found 3 conical dermal 
bones whose bases were buried in the skin, the remainder being covered with horn. Two of 
these are symmetrical and may have been placed on the midline of the upper side of the tail, as 
in Chelydra. However, they are not comprest, but circular in section. The base of one is 10 
mm. in diameter and the height is the same; the other is smaller. The third is unsymmetrical 
and somewhat flattened. It is possible that on the tail were 3 rows of dermal bones or there 
may have been dermal bones on the legs, as in some species of 7"cj<u</o. 

No. 5965 may be regarded as the paratype of the present species. It furnishes only the 
carapace and plastron. It was secured in 1903, at Grizzly Buttes, Wyoming. The carapace is 
more complete than that of the type and has furnisht plate 15. The length is 333 mm. along 



74 FOSSIL TURTLES OF NORTH AMERICA. 

the midline. The height, after some crushing, is still 132 mm. The scallops of the hinder 
border are shallow. The surface of the carapace is sculptured as in the type. The symmetrical 
ridges and grooves found in B. arcnosa and B. riparia are here obscure. On the hinder half of 
the carapace there are a few irregular longitudinal folds and a system ot anastomosing 
ridges and pustular elevations. The outer ends of the costal scute areas, the marginal areas, 
and the whole anterior half of the carapace are much smoother. The nuchal scute is not 
divided. On each of the bridges there were four inframarginal scutes. The bridge region of 
fig. 53 has been completed from this specimen. 

No. 5907 of the American Museum was collected in 1903 by the writer at Grizzly Buttes, 
Wyoming. It may be regarded as a second paratype. It furnishes the shell, fragments of the 
skull, the pelvis, and some limb bones. The shell appears not to have been distorted by 
pressure. The plastron has exactly the length of that of the type. The width of the carapace 
is 290 mm.; the height above the bottom of the plastron, 150 mm. On the right bridge there 
are only 3 inframarginal scutes, and the pectoral scute joins the sixth marginal. On the carapace 
the nuchal scute is not divided longitudinally. On each side, as in the other specimens, is a 
small marginal followed by a much larger one, that on the right side being larger. The super- 
numerary costals are not found at the sides of the first vertebral. 

The pelvis is represented by fig. 54. The shaft of the ilium, where narrowest, has a diam- 
eter of 10 mm. The expanded head is 34 mm. high and 33 mm. wide, while in Chisternon 
undatum the head is considerably higher than wide. The pubis is thin, 4.5 mm., slightly 
convex above, concave below. The pelvis resembles closely that of the type of B. arenosa. 

Fig. 55 is that of the distal end of the humerus, seen from above. The radius is a terete 
bone 57 mm. long. Fig. 56 represents one of the digits. The right femur is 78 mm. long and is a 
stout bone with a minimum diameter of 8 mm. The plane passing thru the strongly comprest 
head falls outside the tibial border of the distal end far less than in a specimen of Trachemys 
elegans. The tibia had a length somewhat exceeding 63 mm., and the least diameter of the 
shaft is 7 mm. The distal end of the fibula has a width of 13 mm. 

The greater portion of the lower jaw is present and it is of the same heavy construction as 
that of the type. Fragments of the roof of the skull show that the bones in the midline, behind 
the orbits, were 7 mm. thick. 

Baena clara sp. nov. 
Plate 16, figs. I, i; text-figs. 57, 58. 

This species is based on a nearly complete shell which was collected by the American 
Museum expedition of 1893. It was obtained in the Bridget beds of Wyoming and bears the 
number 1675. The exact level and locality are not known. Only unimportant portions of the 
front of the carapace are wanting. 

The extreme length of the carapace (plate 16, fig. i) is 362 mm.; its width across the middle, 
where it is widest, is 300 mm. The shell is but little distorted by pressure. It is elegantly oval 
in form, with the edges of the hinder border of the carapace furnisht with shallow scallops, 
and with a deep excavation in the rear, as if for a large tail. The shell is flat transversely in the 
region occupied by the vertebral scutes. There is no carina, except along the fifth vertebral 
scute. Immediately in front of this, for a short distance, there is a narrow median ridge, like 
that seen in B. arenosa. Over and behind the posterior legs the shell is flared outward and 
slightly upward. In front and behind the bone is rather thin; but anteriorly it soon thickens, 
so that over the fore legs it has a thickness of about 15 mm. At the sides the margins of the 
shell are massive. 

The carapace is smooth, with only some faint indications of the sculpturing seen in B. 
arenosa. 

The plastron (plate 16, fig. 2; text-fig. 58) has a length of 333 mm. in the midline. It was 
flat as far out as the bridges. From the inner ends of these the plastron rises upward and 
outward to the margins of the carapace, so that the latter stands some 50 mm. above the level 
of the plastron. The highest part of the shell stood above the plastron about 150 mm. 

The anterior lobe of the plastron is tongue-shaped, rounded in front, and feebly notcht. 
In the figures it appears foreshortened, having been prest upward during fossilization. Its 



BAENID^. 



75 



width at its base is 125 mm.; its length in the middle line is 90 mm. At a point half-way 
between the tip and the base the width is 88 mm. The width of the bridge is 145 mm. The 
hinder lobe of the plastron is broadly tongue-shaped, with the tip truncated and broadly 
notcht. At its base this lobe is 125 mm. wide; and in the midline it is 100 mm. long. 

The sutures between the various bones of the shell are usually very obscure, but most of 
them are determinable. The limits of the neurals (fig. 57) are somewhat conjectural. Those 
between the costals and the peripherals run probably close to the sulcus between the costal and 
peripheral bones. The most anterior peripherals, however, rise above this sulcus. 

The sutures of the plastron are hard to trace. Only the general course of those limiting the 
entoplastron and the epiplastra is discernible. The sutures between the bones of the plastron 
and the peripherals lie about 44 mm., mesiad of the shell margin. At a point about 40 mm. 
behind the axillary notch is observed the suture between the hyoplastron and the mesoplastron. 
Its course is inward and somewhat backward to a point in the midline about 66 mm. behind the 
line joining the axillary notches. Another distinct suture may be observed about 38 mm. in 
front of the inguinal notch on the left side. It can be traced toward the midline, where it 
becomes obscure. This suture is that between the mesoplastron and the hypoplastron. Thus 
the inner ends of the mesoplastron are about 24 mm. wide. 



57- 





Figs. 57 and 58. — Baena clara. Type. Xi- 
57. Carapace. 58. Plastron. 

At a point in the midline about 45 mm. behind a line joining the inguinal notches the 
sutures between the hypoplastra and the xiphiplastra are seen running nearly directly outward. 

The impressions defining the epidermal scutes are usually very distinct. The sides of the 
vertebral scutes are bracket-shaped. The lateral boundaries of the first vertebral run nearly 
parallel and the scute is nearly as wide in front as it is behind. It has a length of 56 mm., a 
posterior breadth of 63 mm., and an anterior breadth of about 58 mm. The lateral sulcus 
on the left side is deflected somewhat toward the right side as it passes forward. It is possible 
that an accessory lateral scute is cut off from the front of the usual first lateral scute and lies 
to the left of the first vertebral. It is provisionally represented in the diagram above. 



76 FOSSIL TURTLES OF NORTH AMERICA. 

The second vertebral scute is 90 mm. long in the midline, and is 72 mm. wide across its 
middle. Similarly, the third scute is 87 mm. long and 72 mm. wide; the fourth, 75 mm. long, 
deeply concave behind, and 75 mm. wide. The fifth scute is 35 mm. long and 100 mm. wide. 
Its posterior edge comes to the border of the shell, there being no supracaudal. 

The anterior marginals are somewhat damaged. In front there is a nuchal scute 30 mm. 
from side to side and 16 mm. fore and aft. On the right side there are 2 small marginals, 
each about 15 mm. long. On the left side there is I, perhaps 2, corresponding marginals. Then 
follows, on each side, a marginal about 44 mm. long, succeeded by several others of about 
the same or greater length. Further behind they shorten gradually, and the last one is very 
small. The first long marginal has a height of 20 mm. at its middle; the majority of them 
have a height of about 38 mm. Further behind the height is less. 

The sulcus running along the midline of the plastron pursues a very irregular course, and 
the same is true of some of the others. That behind the gulars runs from the midline 
outward and backward for half its length, thence forward and outward. That defining the 
intergulars does not, at the midline, quite reach the one behind the gulars. The pectorals are 
about 87 mm. wide at the midline; the abdominals about 35 mm. 

The sulcus between the femorals and the anals is extremely irregular. The right 
femoral at the midline is 62 mm. wide, the left, 78 mm. wide. There are four inframar- 
ginal scutes. The first, or axillary, is 58 mm. long and 40 mm. wide; the second has the form 
of a trapezium, with outer and hinder borders each about 40 mm.; the third is four-sided, 
50 mm. long, 60 mm. wide. The inguinal scute is pentagonal, about 46 mm. long and broad. 

A second specimen belonging apparently to this species, No. 5957 of the American Museum, 
was collected in the Bridger beds in 1903. It has the first vertebral scute symmetrical, 43 mm. 
wide in front, 65 mm. wide posteriorly. There is on each side of it a triangular super- 
numerary costal scute. 

From B. arenosa the present species differs in displaying with considerable distinctness 
the sutures between the various bones. In no specimens oi B. arenosa that have hitherto been 
collected have the sutures of the carapace been observed. It is unlikely that this disappearance 
of the sutures is due to greater age of the specimens of B. arenosa. Furthermore, the cara- 
pace of B. arenosa has a quite elaborate sculpturing along the middle of the back. Of this 
B. clara shows only the merest suggestions. The rear of B. clara is scallopt, but the cuts 
are much shallower than in the other species. The vertebral scutes of B. clara are narrower 
than those of B. arenosa. However, the most striking differences between B. clara and the two 
species above mentioned are found in the shape of the shell. The outline of B. clara is oval. 
The widest part is across the middle of the length and from this the border curves gracefully 
toward the front and rear. In B. arenosa the outline is somewhat quadrate. The sides are 
approximately parallel as far back as the rear of the plastron; then the border turns abruptly 
toward the midline. 

Baena riparia sp. nov. 
Plates 17, i8; plate 19, figs. 1-3; teit-figs. 59-66. 
Baena arenosa, CoPE, Vert. Tert. Form. West, 1884, p. 148, plate xvii, figs. I, 2 (not of Leidy). 

Baena riparia has as its type a fine shell and skeleton, a prize of the American Museum 
expedition of 1903 into the Bridger deposits of southwestern Wyoming. It was found at the 
Grizzly Buttes, about 15 miles southeast of Fort Bridger. The beds belong to those designated 
as B. The specimen is in the American Museum of Natural History and has the number 5977- 

The carapace (plate 17; text-fig. 59) of this specimen is slightly crusht on the left side 
and the hindermost peripherals are mostly gone; otherwise the shell is complete. The cara- 
pace is especially valuable because the bones are not co-ossified, and practically all the 
elements may be determined. It has an axial length of about 315 mm., a slight dislocation of 
the bones of the rear making the estimate inexact. The width is 260 mm. From the middle 
of the length the width decreases gradually to the somewhat projecting front. The rear has a 
wide but shallow sinus over the tail. In fig. 59 the outline of the rear behind the eighth periph- 
eral to near the pygal is somewhat conjectural, but must be close to the real condition. 
Along the middle of the back there runs a distinct channel which extends out beyond the 
neural bones. Along the middle of this there is seen a narrow ridge, on each side of which 



BAENID^. 



n 



is a groove. From a point a little behind the center of each vertebral scute a few folds radiate 

to the ends and angles of the scutal areas. Outside of these areas the surface of the shell is 

somewhat uneven. 

The anterior neurals are widest in front, very narrow behind. The three or four posterior 

are wider. The sutures are somewhat irregular. Only 7 neurals can be determined. The 

seventh is larger than the others and corresponds to the seventh 
and eighth costal plates; but no suture can be seen crossing it. 

The nuchal bone is slightly broader than long, 46 mm. by 35 
mm. The pygal, somewhat damaged, is broader than long. 
The peripherals do not differ greatly in height, this being about 
27 mm. There were apparently 12 of these bones on each side. 
The sulci are distinctly imprest, but narrow. The nuchal 
scute is distinctly divided into a right and a left. At each side of 
it is a minute triangular first marginal. The second marginal is 

33 mm. long on the free border; the third, 39 mm.; the eighth, 38 mm. The dimensions of 

the vertebral scutes are shown in the table. 



Vertebral. 


Length. 


Width. 




44 


48 




7* 


S' 




73 


57 




68 


61 




5o± 


9o± , 





Figs. 59 and 60. — Baena riparia. Type. Xj. 

59. Carapace, showing bones and scute areas. 

60. Plastron, abj abdominal scute; isn, anal scute; ent^ entroplastroa; epi, epiplastron; /fm, femoral scute; g, 

gular scute; hum^ humeral scute; hyo, hyoplastron; hypo, hypoplastron; rn/m, inframarginal scutes; 
mei, mesoplastron; ptc, pectoral scute; xiph, liphiplastron. 

There are on each side 5 costal scutes, a small supernumerary one being situated on each 
side of the first vertebral. Whether there are 13 or 14 marginals is uncertain. There is no 
supracaudal scute occupying the midline over the tail. 

The plastron (plate 18; text-fig. 60) is 262 mm. long on the midline. Its width is close to 
200 mm. As in the other species of the genus, it sends upward strong axillary and inguinal 
buttresses. The former rise to within 25 mm. of the first dorsal vertebra. They are joined 



78 



FOSSIL TURTLES OF NORTH AMERICA. 



by the ribs of the vertebra mentioned. These buttresses extend inward from the sides of the 
shell, forming partitions whose inner borders are distant from each other 85 mm. The upper 
ends of the inguinal buttresses rise high against the contiguous borders of the fifth and sixth 
costal plates. Between the axillary and the inguinal buttresses of each side there is a deep 
sternal chamber. 

The anterior lobe is 70 mm. long, 90 mm. wide at the base, and 64 mm. at the gulo-humeral 
sulci. It contracts gradually to these sulci, then sweeps round to the midline. The free 
border is obtuse and the greater part of the lobe is 10 mm. thick. The entoplastron is long and 
narrow, its length being 45 mm., its width 26 mm. The mesoplastra fail by about 16 mm. of 
reaching the midline. Laterally they expand to a width of 64 mm. The bridges are 1 16 mm. 
wide — 62 per cent, of the length of that part of the plastron behind the axillary notches. 

The hinder lobe is 78 mm. long, 1 14 mm. wide at the base, and 80 mm. at the femoro-anal 
sulci. The hinder border is slightly notcht. The free borders are subacute. At the inguinal 
notch the thickness of the bone is 18 mm., but backward it thins to about 4 mm. 

The intergulars and the gulars both overlap the entoplastron. On each bridge there are 
3 inframarginals, an axillary, another at the end of the pectoro-abdominal sulcus, and an 
inguinal. The pectoral scute comes into contact with the sixth marginal. 




Figs. 61-66. — Ba'ena riparia. Type. 



61. Scapula. 

62. Coracoid. 

63. Humerus, dorsal view. 

64. Humerus, radial border. 




65. Femur, dorsal view 

66. Right hind leg. 
66a. Femur. 



The skull (plate 19, figs, i, 2) of this specimen is considerably 
damaged. Most of the temporal roof is missing, as are the squa- 
mosals and the premaxillae. The length from the latter bones to 
the occipital condyle was close to 57 mm.; the breadth across the 
quadrates is 56 mm. The orbit has a perpendicular diameter of 17 
mm., a horizontal diameter of 15 mm., being somewhat larger than the orbit of 5. sima, which 
had a larger skull. The interorbital space is 18.5 mm. wide. The nasal opening is 17 mm. 
wide. The narrowest part of the pterygoids is 13 mm. wide. On the inner border of the tritu- 
rating surface of each maxilla there is a sharp ridge, as in B. sima. 

The lower jaw (plate 19, fig. 3) of this species differs greatly from that of 5. sima, being of 
much lighter construction and having a shorter symphysis. The distance from the tip of the jaw 
to the middle of a Hne joining the front of one articulatory surface for the quadrate with that 
of the other is 40 mm., the same as in the type of 5. sima. The distance from the outside of one 
of the articulatory surfaces to the other is 50 mm., much less than in B. sima. The height 
of the middle of a ramus is 10 mm., the thickness 7 mm., the width of the gutter-like triturating 
surface 4 mrti. The length of the lower side of the symphysis is 15 mm. Of the sutures of the 
upper surface of the skull the median, running between the nasals, prefrontals, frontals, and 
parietals, and the transverse which separates the parietals from the frontals, are determinable. 



BAENID^. 79 

The course of the parieto-frontal suture is different from that of Chisternon hebraicum, since 
mesially it is placed further forward and runs outward and somewhat backward to the orbit. 
The upper surface of the skull appears to have been covered with horny scutes. 

All of the cervical vertebrae are present, except the first. The whole series had a length of 
close to 100 mm., not quite one-third the length of the carapace. All have transverse processes. 
All have a sharp crest on the lower side of the centrum. These crests are so deep that they 
would have interfered greatly with any considerable flexure of the neck in a perpendicular 
plane. The second centrum is flat anteriorly, very concave posteriorly. The third is moder- 
ately convex in front, deeply concave behind. The fourth has the anterior end concave in the 
center, but the concavity is surrounded by a broad convex wall. The hinder end is shallowly 
concave. The fifth is rather deeply concave in front, flat behind. From the outside of one of 
the postzygapophyses to that of the other of the vertebra is 13 mm. The centrum of the sixth 
cervical is concave in front. The form of the hinder end can not be observed. The front of 
the seventh is concave, the hinder end flat. The eighth is concave in front; the hinder end is 
quite convex, but small. The first dorsal has a large concavity to receive the convex surface 
of the eighth cervical. This concavity looks directly forward, as in the Pleurodira, not down- 
ward as in the Cryptodira. This is another indication that the head and neck were not 
retracted within the shell. In the hindermost of the cervicals the zygapophyses stand high 
above the centra. Furthermore, the ends of the centra, especially when they are flat or 
convex, are considerably higher than wide. Both these conditions would be unfavorable to 
the flexure of the neck in a perpendicular plane. The postzygapophyses of the last cervical 
and the prezygapophyses of the first dorsal are short, not long and curved like those of the 
Cryptodira. On the other hand, the lateral motion of the neck could hardly have been so free 
as in the Pleurodira; and there was no projecting roof of the carapace under which the head 
could be concealed. We must conclude that these turtles could protect their heads hardly more 
than the sea-turtles. 

The ascending portion of the scapula (fig. 61) is long and slender; as is also the precoracoid 
process. The coracoids (fig. 62) are somewhat damaged; but it is evident that the median end 
was not greatly expanded, not so much as in some Emydidae. The humerus (figs. 63, 64) is 
67 mm. long. The shaft is little bent. The distance from the outside of the radial process to the 
outside of the ulnar is 27 mm. The breadth of the distal end is 21 mm. The ectepicondylar 
foramen is situated 9 mm. above the condyle. The humerus is slightly longer in propor- 
tion to the length of the carapace than in Graptemys, but not so long as in Chelydra. The 
ulnar process does not extend so far above the head as in Chelydra. The remainder of the 
fore limb is missing. 

The pelvis is badly crusht, but there appear to be no striking differences between it and that 
of Chisternon hebraicum (figs. 85, 86). The ossified prepubic process is long, and it resembles 
that of the species just mentioned. The femur (figs. 65, 66) is 68 mm. long and moderately bent. 
In proportion to the length of the carapace the femur is shorter than that of Graptemys and 
still shorter than that of Chelydra. The tibia and the fibula (fig. 66) are each 53 mm. long. 
The tarsal bones and some of the metatarsals are preserved. The second metatarsal is 21.5 
mm. long. This appears to indicate a rather long foot. 

The tail was long. Eleven of the vertebrae are preserved, having a length of 143 mm.; 
and there were evidently several more. So far as determinable, they were convexo-concave. All 
probably bore chevron bones. Some of the anterior caudals have, in the position of the neural 
spine, a rounded boss, as if for the support of a distinct bone, such as occurs on some of the 
caudals o( Chelydra. 

The specimen figured and described by Cope (Vert. Tert. Form. West., p. 148, pi. xvii, 
figs. I, 2) as Baena arenosa is now in the American Museum of Natural History and has the 
catalog number 11 12. Cope's figures are one-fourth the size of nature and are inverted. His 
measurements are in some cases erroneous. The carapace is 320 mm. long, instead of 450 mm. 
The carapace is somewhat crusht and its transverse diameter was nearer 260 mm. than 240 mm. 
The length of the plastron is 290 mm. The anterior lobe is 82 mm. long; the posterior lobe 
87 mm. The width of the base of the anterior lobe is 102 mm.; that of the base of the posterior 
lobe, 116 mm. The width of the anterior at the gulo-humeral sulci is 71 mm.; that of the 



8o 



FOSSIL TURTLES OF NORTH AMERICA. 



posterior at the femoro-anal sulci, 87 mm. As stated by Cope, there are three inframarginal 
scutes on each bridge. The present writer regards the specimens as belonging to B. rtparia. 
The sutures are obliterated. 

Baena emilise sp. nov. 
Plate 20, figs. I, 1; text-figs. 67, 68. 

The type of this species is a nearly complete shell, No. 1925, of the American Museum of 
Natural History and was collected in 1894, by Mr. O. A. Peterson, in the middle Uinta of Utah. 
Through pressure the left side has been crusht in and small portions there are missing; the 
edges of some of the posterior right peripherals are also broken off. On one side or the other 
all parts are present. The elements of the shell are not co-ossified, and we are therefore able 
to determine the limits of nearly all the bones entering into its composition. 

The length of the carapace, measured in a straight line, is 368 mm. (plate 20, fig. i; text- 
fig. 67). Its greatest width, taken at the middle of the length, is 294 mm. — almost exactly 
the size of the specimen described as B. clara and not much smaller than the specimen of B. 
arenosa, No. 1 1 15 of the American Museum. It may therefore be conveniently compared 
with them. 



67. 




.-A 



q 


f 











\ 



Figs. 67 and 68. — Baena emiUte. Type. Xj. Shows bones and scute areas. 
67. Carapace. 68. Plastron. 

The form is much like that of 5. arenosa, being rather wide behind, 245 mm. at the hinder 
end of the plastron. The posterior border is furnisht with 5 or 6 scallops, the cuts between 
which are of a depth intermediate between those oiB. arenosa and B. clara. The upper midline 
is slightly channeled, except on the last vertebral, where there is a prominent carina. 

The plastron (plate 20, fig. 2; text-fig. 68) resembles in general that of the other species, 
but the anterior and the posterior lobes are comparatively narrow. The total length is 320 mm. 
The anterior lobe has a length of 80 mm., a width of 1 10 mm. The tip is evenly rounded, the 
lateral border first convex, then further back concave; so that its width at the middle of its 
length is only 8 1 mm. The posterior lobe has a length of 83 mm. and a width of 122 mm. at the 
base. Its posterior border is nearly straight. The width of the bridge is 160 mm. The plastron 
comes within about 40 mm. of the end of the carapace. 

This species agrees with B. clara in having only 4 costal scutes, instead of 5. The lateral 
margins of the first vertebral are parallel until they meet the marginals. Then the edge of the 



Vertebral. 


Length. 


Width. 




55 


68 




go 


63 




92 


75 




70 


78 




70 


98 



BAENID^. 81 

vertebral runs forward and inward to the midline. The table below gives the dimensions of 
the vertebral scutes. These are narrower than they are in B. arenosa of the same size, and 
the third is longer than in any of the described species. There are 5 small marginal scutes 

lying in front of the first vertebral. Two of these, quadrilateral 
in form, about 26 mm. long and 20 mm. wide, occupy respectively 
the right and left thirds of the front border of that vertebral. A 
pentagonal scute 25 mm. from side to side occupies the middle 
third. It measures 15 mm. fore and aft; and its narrowed front 
scarcely reaches the margin of the shell, since two other small 
scutes come in front of it, one on each side. No sulcus is seen 
along the midline. 

The lateral marginals of B. emilice are higher than they are in 
either B. arenosa or B. clara. The upper border of the one below the anterior angle of the third 
costal scute stands about 50 mm. above the lower edge of the shell. In the specimen of B. 
arenosa, No. 1 1 15, larger than the shell being described, the corresponding marginal hardly 
reaches 40 mm. The upper borders of the marginals of B. emilice appear to follow closely 
the sutures between the peripheral bones and the costal plates. 

There appear to be 13 marginals on each side, including the minute anterior one. 

The epidermal sulci of the carapace are deeply imprest; those of the plastron are rather 
obscure. The intergulars reach about two-thirds the distance to the humero-gular sulcus. 
There is a row of 5 inframarginals on each side. As to the other plastral scutes, it is not 
observed that they are especially different from those of S. arenosa. 

It is possible to trace the sutures between all the bones of the shell, except those surrounding 
a few of the anterior neurals and some of the posterior peripherals; but even these may be 
located approximately. 

It will be observed that the nuchal does not have the great antero-posterior extent that it 
does in the recent Pleurodira. The neurals are in general elongated hexagonal, with the broad 
end forward. The first and second measure together 83 mm., and the front one is probably 
a little the shorter. Of their width one can not be certain. The third is 55 mm. long, and 
apparently 30 mm. wide; the fourth, 43 mm. long, 27 mm. wide; the fifth, 43 mm. long, 31 mm. 
wide; the sixth, 35 mm. long, 32 mm. wide; the seventh, 30 mm. long, and the same in width; 
the eighth, 30 mm. long, and 34 mm. wide. Behind the last neural comes the pygal, 30 mm. 
long and 60 mm. wide. No suprapygal is found between the last neural and the pygal. The 
eighth costal plate occupies the whole lateral border of the eighth neural and, in addition, 
the postero-lateral portion of the seventh neural. 

The nuchal bone has a fore-and-aft extent of 37 mm. Its width from side to side is about 
50 mm. in front and about 85 mm. behind. 

There are almost certainly 12 peripherals on each side. The most anterior sutures are 
easily distinguisht; but, for various reasons, not the posterior ones. Over the bridges the 
sutures between the peripherals are continuous with the sutures between the costal bones; 
posteriorly, there is not this correspondence. The sutures are not traceable, but there is 
undoubtedly one between each two epidermal sulci. 

On the plastron all the sutures are easily distinguisht. The total length of the plastron is 
320 mm. The epiplastra meet in the midline by a suture 13 mm. long; the length of each bone 
is 42 mm. The entoplastron resembles that of B. arenosa, as figured by Leidy (Cont. Ext. 
Fauna W. Terr., pi. xv, figs. 4, 5). Its length is 40 mm.; its breadth 34 mm. The suture 
between the hyoplastra is 96 mm. long. The mesoplastra meet in the midline for a space 
of 33 mm. At their outer ends they are 75 mm. wide. The suture between the hypoplastra 
is 87 mm. long. The xiphiplastral suture is 50 mm. long, and each, measured at its anterior 
end, is 50 mm. wide. The anterior and posterior buttresses of the plastron are like those of 
B. arenosa. 

Theintergularsmeasureon the midline 18 mm.; the gulars, 9 mm.; the humerals, 51 mm.; 
the pectorals, 84 mm.; the abdominals, 42 mm.; the femorals, 64 mm.; the anals, 54 mm. 
On the bridge are 5 inframarginals. 

In the middle line above there are some longitudinal ridges and grooves and some irregular 
elevations, which are rudiments or vestiges of an ornamentation similar to that of B. arenosa. 



82 FOSSIL TURTLES OF NORTH AMERICA. 

This species differs from B. arenosa in the form of the anterior vertebral scute and in 
having no accessory lateral scute. In these respects it agrees with B. clara. From the latter it 
differs in having the shell broader behind, a wider and more deeply scallopt postero-lateral 
border, higher lateral marginal scutes, a different arrangement of the most anterior marginal 
scutes, and narrower plastral lobes. The bridge of the plastron is also wider. It measures 
1 60 mm., while that of the type o( B. clara is only 150 mm. The bridge of/?, arenosa. No. 1115, 
a larger shell, also measures only 150 mm. On the under side of the postero-lateral border of 
the shell, at the fifth scallop, the distance from the line where the soft skin of the animal began 
to the outer edge of the shell is 40 mm.; in B. clara this space is only 33 mm. 

There is in the American Museum's collection a second specimen of this species from the 
same level. It is somewhat smaller, with a total length of 323 mm., and is less perfect than the 
one which has furnisht the above description. Nevertheless, the principal characters distin- 
guishing the species from the others are exhibited. Altho smaller, the sutures have almost 
wholly disappeared, so that it furnishes no aid in tracing these. 

In the collection of Princeton University there is a somewhat damaged shell which is 
referred to this species. The catalog number is 1 1263. It was collected by Mr. J. B. Hatcher, 
in 1895, in the Uinta Eocene, at Kennedy's Hole, Utah. The beds contained remains of 
Dolichorhinus cornutus. 

Genus EUBAENA nov. 

Skull resembling that of Ba'ena, but with the temporal region less extensively rooft over, 
the squamosals not coming into contact with the parietals. Jugals excluded from the rims of 
the orbits. Triturating surfaces of the maxillae transversely broad and concave. Choanae 
opening between the orbits, and at nearly one-third the distance from the snout to the occipital 
condyle. Shell unknown. 

Type : Euba'ena cephalica Hay. 

Eubaena cephalica Hay. 

Plate 19, fig. 4; plate 2t, figs. I, 2. 

Ba'ena cephalica, Hay, Amer. Jour. Sci. (4), xvni, 1904, p. 263, plate xii, figs. 1-3. 

The name Euba'ena cephalica is given to a fine skull which is in Yale University Museum. 
This skull, which lacks only the lower jaw, was collected in the Laramie deposits of Converse 
County, Wyoming, by Professor J. B. Hatcher, then employed by Professor O. C. Marsh. The 
specimen bears Professor Marsh's receipt number 21 10. 

In general form the skull is broad behind, rather flat above, and with pointed snout. The 
length from the snout to the occipital condyle is 67 mm.; to the end of the supraoccipital 
spine, 74 mm. The greatest breadth, just in front of the tympanic chamber, is 65 mm. From 
these chambers the width diminishes to the snout. The flat upper surface of the skull descends 
each way to the perpendicular sides. The sides of the face about the orbits look upward and 
outward, as well as forward. The tympanic opening is nearly circular, 19 mm. in its perpen- 
dicular, 15 mm. in its horizontal axis. The orbit is circular and small, its diameter being 14mm. 
The interorbital space is 25 mm. wide. The nasal opening, as seen from in front, is somewhat 
heart-shaped, and is directed above and forward. From the orbit to the tympanic opening is 
24 mm. ; from the nares to the orbit is 10 mm. 

The temporal region is rooft over, but not so extensively as in species oi Ba'ena from the 
Bridger beds. On each side of the supraoccipital this roof is excavated as far as a line joining 
the anterior borders of the tympanic chambers. From the orbit to the bottom of the excava- 
tion is 22 mm. The hinder end of the postfrontal is interposed between the parietal and the 
squamosal. 

In general, the sutures of the skull are very distinct, but no trace has been found of those 
between the frontals and the parietals. There are distinct nasals, and these and the prefrontals 
resemble closely the same bones in the Bridger species of Baenidae. The prefrontal of each 
side joins the postfrontal, so that the area of the frontal is excluded from the border of the orbit. 
The sagittal suture extends from the prefrontals to the supraoccipital spine, a distance of 



BAENID^. 83 

42 mm. The postfrontal is large, having a length of 32 mm., being in contact by its lower 
border with the maxilla, the jugal, and the quadratojugal; and by its posterior border with 
the squamosal. 

The jugal is small, being only 8 mm. in length and 15 mm. in heigth. The squamosal forms 
the hinder border of the tympanic opening. Superiorly it has a thin crest, a relic of the former 
backward extension of the temporal roof. The tympanic chamber extends backward into this 
bone. The lower border of the zygomatic bar is considerably excavated. Seen from the side the 
maxilla is convex on its lower border. From this border the bone rises 11 mm. to the orbit. 
The premaxillje are distinct from the maxillae and from each other. At the symphysis they are 
only 3 mm. high, but at the union with the maxillae, 10 mm. high. As in the Bridger species 
of Ba'ena there are distinct lacrimal bones. The lower border of each comes into contact 
with the vomer. The jugals are excluded from the rims of the orbits (Plate 19, fig. 4). 

As seen from below, the maxilla has a broad masticatory surface, its width being 14 mm. 
from its inner border to the cutting-edge. The inner border of this surface is furnisht by the 
palatine bone. The latter forms the whole of the outer border of the choana. The masticatory 
surface does not extend forward on the premaxilla. In front of the choanae there is a deep 
groove, which in front expands on the lower surface of the premaxillae. There are postpalatine 
foramina (Plate 21, fig. 2). 

The pterygoids come into short contact with the maxillae. They have distinct ectoptery- 
goid processes. Where the hinder part of the palate is constricted it is 18 mm. wide. The 
pterygoids extend backward to the hinder border of the pedicel of the quadrates, thus sepa- 
rating the latter widely from the basioccipital and basisphenoid. There is a considerable 
groove between the quadrate on each side and the median bones of the skull. The pterygoids 
join in the midline for a considerable distance in front of the basisphenoid. There is on each 
side of the latter bone, about the middle of its length, a venous foramen. 

The pedicels of the quadrates are short. The surface for articulation with the mandible 
is deeply concave from side to side, nearly plane from front to back. 

A pair of epidermal scutes appears to have occupied the space between the anterior 
halves of the orbits. Behind each of these and bounding the hinder half of the orbit was a 
smaller scute. A very large scute, or more probably a pair of them, occupied the area of the 
frontal bones and overlapt behind this on the parietals. The hinder half of this scute, or 
these scutes, if two, was separated by two median scutes. The more anterior of these last was 
circular; the more posterior was broadened backward and lay on the whole or part of the 
supraoccipital processes of the parietals. 

Eubaena latifrons sp. nov. 
Figs. 69, 70. 

The specimen on which the present species is based was found by Mr. Barnum Brown, of 
the American Museum of Natural History, in Laramie deposits, on Seven Mile Creek, Wyom- 
ing, about 40 miles northwest of Edgemont, South Dakota. It has the catalog number 6139. 
The specimen consists of the skull, without the lower jaw. This skull is crusht downward 
somewhat, and the right maxilla is forced inward partly over the triturating surface of that 
side. The left maxilla is missing. A part of the temporal roof is broken away and most of 
the supraoccipital spine is gone. 

It is not impossible that the shell of this species has already been described as one of the 
Laramie species of Ba'ena; but this can not be determined until the skull and the shell have 
been found together. The skull resembles that of £. cephalica; but a number of differences 
exist, which will be mentioned as the description proceeds. 

How far the premaxillx extended beyond the front of the nasal bones can not be deter- 
mined exactly; but the distance appears to have been less than in E. cephalica. It may be 
assumed to have been about 5 mm. The length of the skull, from the front of the nasals to the 
occipital condyle, is 72 mm. The width from one quadratojugal to the other is 73 mm. 
Evidently the orbits looked upward less than in E. cephalica, for the width of the interorbital 
space is 32 mm.; in E. cephalica, only 25 mm. The horizontal diameter of the orbit is 17 mm., 
being thus more than in the species with which it is compared. The tympanic chamber, too, 



84 



FOSSIL TURTLES OF NORTH AMERICA. 



is larger than that of the other species, the horizontal diameter being 24 mm. The perpen- 
dicular diameter is now only 16 mm., but this is due, no doubt, to crushing. From the orbit to 
the tympanic cavity is 22 mm. 

The roofing of the temporal region resembles that of E. cephalica. Few of the sutures of 
the upper side of the skull can be traced with certainty; but it is evident that the parietal 
union with the squamosal had been severed by the excavation in the hinder border of the roof. 
There are reasons for believing that the parietals were each 15 mm. wide posteriorly. If the 
prefronto-nasal suture is where it seems to be, the nasals were unusually large, running along 
the midline 8 mm. The parieto-frontal and the fronto-prefrontal sutures can not be deter- 
mined with certainty. The nasal opening has now a width of 23 mm. One premaxilla is 
present and has the height and the width each 9 mm. The maxilla, below the orbit, is 1 1 mm. 
wide, being thus narrower than that of £. cephalica. 

The upper surface of the skull is rough with narrow ridges, separated by sharp furrows. 
This interferes with the tracing of the sutures; for the latter do not appear to be really absent. 
Occasional narrow grooves indicate that the skull was covered with horny plates; but these 
can not be mapt. 





Figs. 69 AND 70. — Euba'ena latifrons. Skull of type. Xf. 
69. Skull seen from above. 70. Skull seen from below, pmx, premaxilla; ro, vomer. 

The base of the skull and the roof of the mouth resemble in general the same regions of 
£. cephalica. At the pterygoid constriction the width is only 16 mm. The postpalatine 
foramina are placed 24 mm. apart; whereas, in E. cephalica they are only 18 mm. apart. The 
maxillary triturating surfaces appear not to have been so wide as those of E. cephalica. As in 
the latter species, they are bounded on the inner margin by a rough ridge. 

Genus CHISTERNON Leidy. 

Related closely to Baena, but having 2 bones, an anterior and a posterior, occupying the 
region of the nuchal of Baena. Normally 2 scutes occupying the area corresponding to the first 
vertebral oi Baena. No supramarginals. Maxilla with a nearly plane triturating surface. 

Type, Baena undata Leidy. 

The genus was based by Dr. Leidy on the presence of the mesoplastra, but these were after- 
wards found to be present in Baena arenosa also. The existence of the two bones in the region 
of the nuchal, with the absence of supramarginals, will characterize the genus. 

Two specimens of C. undatum and one belonging to Cope's Baena hebraica in the American 
Museum of Natural History show unmistakably the two bones mentioned as occurring in the 
region of the anterior neural. 

Remarks on the significance of the preneural and the supernumerary scutes will be found 
on page ^y. 



BAENID^. 



85 



Chisternon undatum Leidy. 
Plate 22; text-figs. 71-75. 

Baena undata, Leidy, Proc. Acad. Nat. Sci. Phila. 1871, p. 228; U. S. Geol. Surv. Montana, etc., 1871 
(1872), p. 369. — Cope, 6th Ann. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 622; Vert. Tert. 
Form. West, 1884, p. 147, plate xix, Hgs. 3-5. — OsnoRN, Scott, and Spier, Contrib. Mus. Geol. and 
Arch. Princeton Univ., No. i, 1878, p. 96. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 

Chisternon undatum, Leidy, Proc. Acad. Nat. Sci. Phila. 1872, p. 162; Contrib. Ext. Fauna West. Terrs. 
1873. PP- 169, 341, plate xiv, figs, i, 2. 

The type of Leidy's Chisternon undatum is in the collection of the Academy of Natural 
Sciences at Philadelphia. The specimen is said to have been collected in a range of buttes a few 
miles from Fort Bridger. This range is probably Grizzly Buttes and the level is B. The shell 
belonged to a turtle whose carapace had a length of about 485 mm. The front and the rear of 
the shell are missing, so that Leidy could not know the structure of the bones and scutes of the 
front of the carapace. As stated by that author, the shell is rather high and archt, its upper 
surface standing above the bottom of the plastron about 7.5 inches, equal to 190 mm. The 
sutures may be traced by means of the band of striations that crost them, and Leidy wasenabled 
to map correctly the bones of the plastron. The mesoplastra come to a point at the midline. 
The costo-marginal sulci over the bridges run about 50 mm. above the borders of the shell. 





Figs. 71 and J2. — Chisternon undatum. Carapace and plastron. 



71. Plastron of No. 3932 A. M. N. H. X J. Anterior lobe missing. 

72. Carapace of No. 5959 A. M. N. H. X \. Areas of some bones not mapt. 

Many characters given by Cope as distinguishing this species from C. hebrauum are not 
conclusive. There is no appreciable difference in the sizes of the anterior lobes; nor do the 
intergular and gular scutes of C. undatum always start from a common point. So far as the 
writer has observed, the marginal scutes of C. hehraicum rise considerably higher above the 
margins of the shell over the bridges than they do in C. undatum. As will be shown below, 
there are important differences in the skulls. 

In the American Museum there are 4 large shells which are regarded as belongmg to this 
species. In none of these are the boundaries of all the bones to be made out, altho in some ot 
them many sutures may be traced. 

No. 3932 (plate 22; text-fig. 71) was collected in 1893 in the Bridger beds of Wyoming, but 
the exact locality and level are unknown. The length along the midline is 433 mm.; the 



86 



FOSSIL TURTLES OF NORTH AMERICA. 



greatest width, 387 mm. The outlines of many of the neural bones are determinable. On the 
front of the carapace, however, the indications are obscure. The vertebral scutes are a little 
longer than wide. The scutes on the front of the carapace are unsymmetrical. On the left 
side there is a supernumerary costal, but not on the right side. The anterior vertebral is not 
transversely divided as it is in the other specimens. Over the bridges the marginal scutes are 
not more than 45 mm. high. The anterior lobe of the plastron is missing. On the left bridge 
there are only three inframarginal scutes. 

No. 5974 was collected in 1903 near the mouth of Cottonwood Creek, in the level called B^. 
It has a length of 490 mm. along the midline, and a maximum width of 425 mm. The rear of 
the carapace is scallopt. Most of the sutures are indistinct, but the small nuchal and the 
large preneural are plainly separated. The former is 38 mm. long and 46 mm. wide; the latter, 
45 mm. long and 72 mm. wide. The first vertebral scute is transversely divided, so that there 
are present really 6 vertebrals. On each side of the two anterior ones is a supernumerary costal, 
and an extra scute has been cut off from the first vertebral and the right supernumerary costal. 
The marginals over the bridges appear not to run more than 50 mm. above the borders of the 
shell. The plastron is 440 mm. long. The entoplastron has a length of 80 mm. and a width 
of about 45 mm. The mesoplastral sutures are not wholly distinct, but these bones appear 
to have come to a point at the midline. The anterior lobe is 120 mm. long; 150 mm. wide at 
the base; 93 mm. wide at the gulo-humeral sulci. The bridge is 205 mm. wide. The hinder 
lobe has a length of 125 mm.; a width of 155 mm. at the base, 122 mm. at the femoro-anal 
sulci. On each bridge are 4 inframarginal scutes. The gulars meet each other for a dis- 
tance of 13 mm. at the midline. 





73. ^^ --^ 74. 

Figs. 73-75. — Chisternon undatum. Skull of No. 5962 A. M. N. H. Xj. 
73. Skull seen from above. 74. Skull seen from below. 75. Right half and tip of lower jaw. 

No. 5959 (fig. 72) was obtained at Grizzly Buttes, Wyoming, in 1903. The axial length of 
the carapace is 455 mm.; its width, 400 mm. As in No. 3932, there is a broad depression along 
the midline of the carapace. There is a distinct nuchal bone, followed by a larger preneural. 
There are 6 vertebral scutes, whose dimensions are given in the accompanying table. 

There is a small supernumerary costal scute on each side of 
the first vertebral scute and another on each side of the second 
(fig. 72). The border of the shell over the right bridge is crusht, 
but the costo-marginal sulci appear to have run not more than 
60 mm. above the border of the shell. The entoplastron is 80 
mm. long and about 48 mm. wide. On the right bridge are five 
inframarginals. The left bridge is missing. 

No. 5962 was collected at Grizzly Buttes, in 1903. It was 
lying close to No. 5961, a specimen of C. hebratcum. The cara- 
pace is much crusht laterally and diagonally. The specimen is 
valuable because it furnishes the skull. The carapace was at least 460 mm. long. So far as 
can be determined, the costo-marginal sulci pursued their courses above the bridges at a moder- 
ate height. There are 6 vertebral scutes and a pair of supernumerary costals in front. There 
are traces of the suture between the nuchal and the preneural. 

Most of the dimensions of the skull (figs. 73, 74) are presented on page 89. It differs from 
that of C hebraicum especially in the broader triturating surfaces of the maxillae and the broader 



Vertebral. 


Length. 


Width. 




3S 


36 




44 


92 




95 


95 




105 


97 




105 


96 


6 


69 


105 



BAENID^. 



87 



pedicels of the quadrates. There appears to have been only a rudimentary ridge on the 
triturating surface. The sutures between most of the bones may be traced, but those separating 
the frontals from the parietals have not been observed. Nasals were quite certainly present, but 
they are broken away. The lower jaw is present (fig. 75). The triturating surface is trans- 
versely concave and 9 mm. wide. The tip of the jaw is damaged so that the length of the 
symphysis can not be exactly determined; but it was not far from 15 mm. 



Chisternon hebraicum Cope. 
Plate 21, figs. 3, 4; plate 23, fig. 1; text-figs. 76-87. 

Baena hebraica, CoPE, Palseont. Bull. No. I, 1872, p. 463; Proc. Amer. Philos. Soc, xii, 187^, p. 463; 
6th Ann. Report, U. S. Gaol. Surv. Terrs., 1872 (1873), p. 62; Vert. Tert. Form. West, 1884, p. 146, 
plate xix, figs. 1, 2. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 

Baena undata. Hay, Bull. Amer. Mas. Nat. Hist., xxi, 1905, p. 138, figs. 1-3. 

Professor Cope's type of the present species consists of about two-thirds of the anterior 
portion of the carapace and the plastron. It was obtained by him in the Bridger Badlands 
along Cottonwood Creek, Wyoming, and hence in the level known as B. This type is now in the 
U. S. National Museum at Washington. It appears to be necessary to correct some of Cope's 

measurements. The transverse axial width 
is given by him as 500 mm., but it is only 
420 mm. Accordingly, Cope's figures are 
just one-third the size of nature. Cope's 
estimate of the length was also 500 mm., 
but the writer would make it only about 425 
mm. In either case the shell is about as 
broad as long. The length of the anterior 
lobe of the plastron, to a line joining the 
bottoms of the axillary notches, is 125 mm. 
Its width is 147 mm. The bridges are 162 
mm. wide. The hinder lobe has a basal 
width of 160 mm. 

As shown by Cope's figures, the nuchal 
and the anterior marginal scutes have small 
extent at right angles with the free border, 
and the firstvertebral is transverselydivided 
so as to make 6 vertebrals in all. The margi- 
nals over the bridges are higher than long, 
and the corresponding costal scutes become 
thereby about as high as long. There is 
likewise a supernumerary costal scute on 
each side of the first vertebral. 
The shoulder-girdle is present, but has not been wholly freed from the matrix. The 
scapula is at least 90 mm. long from the glenoid fossa to the upper end. At its base the cora- 
coid has a diameter of 7 mm.; at a distance of 65 mm. from the glenoid fossa the diameter is 
65 mm. 

No. 5961 of the American Museum is referred to this species. It was collected in 1903 by 
Mr. L. S. Quackenbush, a member of the museum's party. The locality is Grizzly Buttes, 
not far from the locality where Cope's type was collected. It was found lying in close prox- 
imity with the specimen numbered 5962 and referred to Leidy's Chisternon undaium. Both 
specimens furnisht good skulls and other skeletal parts. Figure 76 represents the carapace 
of No. 5961 ; fig. yy, the plastron. The shell, especially in the region of the distal ends of the 
costals, is thin and fragile and some parts were lost. The right half of the nuchal is gone, the 
rear of the carapace is missing. 

The axial length of the carapace was close to 474 mm. ; the greatest width 435 mm. It was 
moderately convex. The surface is nearly smooth. Along the areas of the vertebral scutes 
are some traces of the sculpture so conspicuous in the case of species oi Baena. Across some of 




Fig. 76. 



'Chisternon hebraicum. Portion of carapace. 
Xj. No. 5961 A. M.N. H. 

c. p. I, front costal plate; c. s, i, first costal scute; n. i, n. 2, 
neural bones; preriy preneural. 



88 



FOSSIL TURTLES OF NORTH AMERICA. 





Neurals. 


Vertebrals. 


No. 






Length. 


Width. 


Length. 


Width. 
70 




44 


4* 


40 




57 


38 


4^ 


lOZ 




6o 


39 


III 


"S 




57 


30 


"5 


'«5 




48 


38 




104 






'' 







the intercostal sutures are a few of the grooves described by Cope. Fortunately the sutures 
between the bones are yet open, so that the whole structure can be observed. The most 
striking feature of the carapace is the presence of two bones in the region usually occupied by 
the nuchal, a small anterior and a large posterior. The anterior bone (fig. 76, ««./>), here regarded 
as the true nuchal, has awidth of 52 mm. and a length, fore and aft, of 30 mm. The other bone, 
the preneural (fig. 76, pren), is 75 mm. wide and 38 mm. long. The first neural is pyriform, 
the others hexagonal, with the wider end forward. 

The first three peripheral bones are each 42 mm. high. 
Those over the bridges have a height of about 65 mm. 
There are 6, instead of 5, vertebral scutes, the areas usually 
covered by the first being transversely divided. The dimensions 
of the neurals and vertebrals are shown in the table. 

The nuchal scute is small and was probably not divided 

along the midline. It is 24 mm. wide and 10 mm. fore and 

aft. The first marginal is small and triangular. The second 

has a length of 25 mm. along the free border and a height of 16 

mm. The third is not so high. Those marginals over the 

bridge rise above the borders of the costal bones and have 

a height of approximately 70 mm. 

A little of the hinder border of the plastron (fig. yy) is broken away, but the total length 

was very close to 415 mm. In general it resembles the plastron of species oiBaena. The length 

of the anterior lobe is 113 mm.; its width at the base, 160 mm.; at the outer ends of the gulo- 

humeral sulci, 85 mm. The entoplastron is 65 mm. long and 45 mm. wide. The symphysis of 

the epiplastra is only 14 mm. long. From 
the entoplastron the hyoepiplastral sutures 
run outward and backward. The bridge 
has a width of 180 mm. The mesoplastra 
join at the midline for a distance of 20 mm., 
the left one being somewhat the wider. 
They expand outward to awidth of 105 mm. 
The length of the hinder lobe was 
originally about 105 mm. Its basal width is 
175 mm.; at the hypoxiphiplastral suture, 
145 mm.; at the femoro-anal sulci, 120 
mm. The thickness of the center of the 
anterior lobe is 11 mm. Between the 
axillary buttresses, on the upper surface, 
runs a broad ridge which thickens the bone 
to 15 mm. A similar ridge crosses from 
one inguinal buttress to the other. From 
the latter buttresses a ridge runs backward 
near each free border of the hinder lobe, and 
thru these the thickness is 17 mm. The 
central part of the hinder lobe is concave. 
The skull (plate 21, figs. 3, 4; plate 23, fig. i; text-figs. 78-81) of this specimen is nearly 
complete, lacking only a part of the left maxilla, and the premaxillae. At the time the writer 
publisht his figures of this skull, he had not yet discovered the differences between this 
specimen and that numbered 5962, described here as Chisternon undatum. In order to allow 
comparisons the measurements of the two skulls are given in the table on p. 89. 

There is a difference of only 5 mm. in the lengths of the skulls. There is a difference of this 
same amount in the widths of the maxillae below the orbits, a difference of 8 mm. in the widths 
of the skulls at the quadrates, a difference of 6.5 mm. in the distances from the orbit to the 
tympanic cavity. 

The skull is short, broad behind, wedge-shaped in front. The temporal region is broadly 
rooft over and the squamosal comes into contact with the parietal. 




Fig. 77. — Chisternon hehratcum. Plastron. Xj. No. 
5961 A. M. N. H. Shows bones and scute areas. 



BAENID^. 



89 



Nasals are present. The frontals are triangular, with one apex directed to the corre- 
sponding orbit, without reaching it. The exoccipitals meet in the midline neither above nor 
below the occipital foramen. The occipital condyle belongs wholly to the basioccipital. On 
the lower side of the skull the pterygoids exclude the quadrates from contact with the basioc- 
cipital and the basisphenoid. The latter bone does not quite reach the vomer. On each side 



Length from front of maxilla to occip. condyle . . . 

Width across the quadrates 

Diameter of tympanic cavity 

Breadth of temporal roof from orbit 

Diameter of orbit ■ 

Interorbital space 

Breadth of maxilla below orbit 

Width of pterygoids 

Width of hinder end of maxilla from outside of 

cutting-edge to suture with palatine 

Orbit to border of tympanic cavity 

Width of pedicel of quadrates on level with palate 16 



Chisternen 


Chiiternon 


hebraicuTttf 


undatum. 


No. 5961. 


No. 5962. 


67 


7» 


69 


77 


16.5 


21 


24 


29 


20 


23.5 


20 


^3 


8 


'3 


17-5 


>7-S 


II 


■5 


18.5 


^5 



of the basioccipital is a foramen, doubtless for a vein, wrongly regarded formerly by the 
author as for the internal carotid artery. 

The choanx are placed far forward. There is no masticatory ridge on the maxilla. Just 
within the rim of the orbit there is a distinct suture which cuts off the lacrimal from the 
prefrontal. 

The lower jaw (fig. 8i) presents a rather broad grinding surface. 

The femora of this specimen are present. The total length is 107 mm. The head is 
comprest. The plane passing through this head would come into contact with the tibial 



78. 





Figs. 78 and 79. — Chisternon hehraicum. Skull. Xf . No. 5961 A. M. N. H. 

78. Seen from above, jr, frontal; mx^ maxilla; na, nasal; pa^ parietal; pro, prootic; iq, squamosal. 

79. Seen from below, y'u, jugal ; mx-, maxilla ; /)d/, palatine; /)/, pterygoid; yu, quadrate; yw. ar/, articulation 

of lower jaw; sq, squamosal; vom, vomer. 

border of the distal end of the bone. In Trachemys elegans this plane makes an angle of 
perhaps 40° with the axis of the bone on the tibial side. The diameter of the shaft of the femur 
of the species here described is II mm. The width of the distal end is 31 mm. 

No. 5904 of the American Museum was also found at Grizzly Buttes. It is believed to 
belong to the present species. It furnishes a large shell nearly complete, a portion of the skull 
and lower jaw, the neck, the shoulder-girdle, and the complete pelvis. The carapace has an 
axial length of 505 mm., and a maximum width of 470 mm. The carapace is moderately convex 



9° 



FOSSIL TURTLES OF NORTH AMERICA. 



above and the bridges rise considerably above the bottom of the plastron. The outline of the 
carapace is somewhat pointed in front and furnisht behind with rather shallow scallops. 
In the midline behind is an excavation about 8o mm. wide. As in the other carapace the bones 
are rather thin. The specimen has the characteristics pointed out by Cope as distinguishing 
his Ba'ena hebratca, the presence of coarse grooves across the intercostal sutures and the high 
marginal scutes over the bridges. The bones are thoroly co-ossified and no certain traces 
can be seen of the suture between the nuchal and the preneural. The dermal sulci are mostly 
distinct, but even these are obscure in the front of the carapace. The vertebrals are as in No. 
5961. The marginal below the front of the first costal scute, probably the fourth, has a height 
of about 35 mm.; two over the bridge have a height of 85 mm. 

The plastron presents no novel features, its sutures and sulci being obscure. 

The hinder portion of the skull is present, as well as the lower jaw. Its width behind is 
90 mm. The temporal roof extended backward somewhat further than in No. 5961, but this 



con 






pmx 




Figs. 80 and 81. — Chisternon hebraicum. No. 
5961A.M.N. H. Fig.8o, xf. Fig.Si.X.^ 

80. Skull from right side. Cond, occipital condyle; /r, 
frontal; _/w, jugal ; lay lacrimal; mXf maxilla; 
nd, nasal ; pa^ parietal ; pmx, premaxilla ; qj, 
quadra-tojugal; qu, quadrate; sq, squamosal. 



Fig. 82. — Chisternon hebraicum. 
X'i. No. 5904 A. M. N. H. 

End views of third, fourth, sixth, and 
eighth cervical vertebrae. On the right 
side the anterior ends; on the left, the 
hinder ends. 



may be due to greater age. Over the brain-case the bone is 9 mm. thick. The lower jaw is 
nearly complete. From the tip to the middle of a line joining the hinder ends of the rami the 
distance is about 60 mm. The symphysis measured about 20 mm. The triturating surfaces 
are concave in both directions; their width, 9 mm. The coronoid process stood 23 mm. above 
the lower border of the bone. 

The neck had a length of 165 mm., about one-half of the length of the dorsal part of the 
column (figs. 82, 83). The zygapophyses are high and not far removed from the midline. 
There is a sharp crest on the lower midline of each centrum. The second and third are con- 
vexo-concave; the fourth, biconcave; the fifth to the eighth, concavo-convex. The neural 
arches appear to be co-ossified with the centra. Fig. 84 represents the scapula. 

The pelvis is shown in figs. 85 and 86. The ilia, the ischia, the pubes, and the epipubic 
process are all solidly co-ossified. The expanded upper end of the ilium has a height of 52 mm. 
and a width of 42 mm. The posterior articular end of the centrum of the second sacral 



BAENID-a:. 



91 



(fig. 87) has its upper half very little concave, while the lower half is slightly convex and uneven. 
The anterior articular surface of the first caudal is decidedly concave, but not so much so as is 
the hinder end. 

On the upper surface of each xiphiplastron is a depression about 30 mm. long and half as 
wide. The inner borders of the two are 55 mm. apart. The tuberosities of the ischia appear 
not to have fitted into these depressions, for they are less than 55 mm. apart. From each of the 




Figs. 83-87. — Chisternon hehraicutn 
5904 A. M. N. H. 

83. side view of all the cervical vertebrsc. 

ends toward the left. Xn- 

84. Scapula. Xi- 

81;. Pelvis, from right side. Xi- 

86. Pelvis, from below. Xi. 

87. Sacral vertebrae and ribs. Xj. 



tuberosities there projects backward a long pointed process that must have extended somewhat 
behind the hinder border of the plastron. The lateral processes of the pubes rested on the 
hypoplastra at points about 25 mm. inside the free borders of the hinder lobe. 

Genus BOREMYS Lambe. 

Boremys, Lambe, Ottawa Naturalist, xix, 1906, p. 232. 

Like Baena, but having on each side supramarginal scutes, which alternate with the 
costal scutes. Nuchal bone short and wide. A preneural present. 
Type : Boremys pulchra Lambe. 



g2 FOSSIL TURTLES OF NORTH AMKRICA. 

Boremys pulchra Lambe. 

Figs. 88, 89. 

Baena hatcheri, Lambe, Geol. Surv. Canada, Contrib. to Canad. Palaeont., Ill (410), pt. 2, 1902, p. 43, 

fig. 8. 
Bdena pulchra, Lambe, Ottawa Naturalist, xix, 1906, p. 187, plate iii, fig. 4; pi. iv. 
Boremys pulchra, Lambe, Ottawa Naturalist, xix, 1906, p. 232. 

The type of the present species belongs in the collection of the Geological Survey of Canada. 
It, together with at least one other specimen, was collected by Mr. Lawrence M. Lambe, of the 
Survey, from beds belonging to the Belly River series, equivalent to the Judith River beds. The 
locality is the mouth of Berry Creek, on the Red Deer River, Alberta. The type consists of 
the anterior half of the carapace and the complete plastron. The other specimen furnishes the 
anterior portion of the carapace only. Through the kindness of the discoverer of the species the 
writer has had the opportunity of examining it. 




Fig. 88. — Boremys pulchra. Carapace of type. Xj. From Lambe's figure. 
pren, preneural; sm, supramarginal scutes. 

The specimen was originally referred to Baena hatcheri for the reasons that it was not then 
generally accepted that the Judith River formation was distinct from the Laramie, that the 
specimen is somewhat crusht, that it resembles in various ways B. hatcheri; and for the reason 
finally that the presence of the supramarginals was then overlookt. The broader front of the 
carapace was noted and caused some hesitation. The presence of the supramarginals and 
the small preneural makes the separation of the species as the type of a new genus justifiable. 

The type specimen was a rather small individual, having close to three-fifths the length of 
the type of Baena riparia and a little more than one-half that of B. hatcheri. The carapace 
(fig. 88) had a length of about 195 mm. It is doubtful whether the width has been increast 
by the crushing to which it was subjected. 

The front of the carapace is considerably broader and more rounded than that of B. 
hatcheri. The neurals, so far as preserved, appear to differ in no important respect. The 
first appears to be transversely divided into two parts. The anterior portion is to be regarded 
as a preneural, such as is seen in Chisternon. The shortness of the nuchal bone is remarkable. 
Whereas, in B. hatcheri and other specimens oi Baena which reveal the sutures, the nuchal has 
about the same fore-and-aft length as the first neural, in Boremys pulchra the nuchal is not 
one-half as long as the neural. Its width is about 4 times its length. 



BAENID^. 



93 



The scutes in tront of the first vertebral are more symmetrically arranged than in Ba'ena 
hatcheri; but in Ba'ena and possibly in Boremys these scutes are subject to great variation. 
The vertebrals are slightly longer than broad. In B. hatcheri they are much broader than long. 
There is an accessory, or supernumerary, costal scute on each side of the first vertebral. In 
species oi Ba'ena one or both of these may be absent. The presence of large supramarginals 
(fig. 88, sm) is surprising. In Macrochelys there are three or four of these on each side; but 
these are comparable in size and position with the marginals. In Boremys pulchra, on the 
contrary, the supramarginals are as long fore and aft as are the costals and alternate with them. 

The plastron (fig. 89) has a length of about 172 mm. The anterior lobe is slightly narrower 
than that of B. hatcheri. The entoplastron is long and narrow. The bridge is somewhat 
narrower relatively to the length of the plastron than in B. hatcheri. The mesoplastra join 
along the midline for a space of about 14 mm. The hinder lobe seems to differ little from that 
of the species just mentioned. The intergulars are small and do not reach back on the ento- 
plastron, thus differing from those of 5. hatcheri. 




Fig. 89. — Boremys pulchra. Plastron of type. X^. From Lambe's figure. 
Genus NEURANKYLUS Lambe. 

A genus of uncertain position and known only from a portion of the carapace of the type 
species. Eighth neural large, followed by an expanded suprapygal. In the type a ninth pair 
of costal bones. The vertebral scutes nearly twice as wide as long. 

Type: Neurankylus eximtushambe. 

This genus is placed provisionally in the Ba'enidce. When the last neural of Neurankylus 
eximius is compared with that of Ba'ena riparia they are seen to be very similar. The pre- 
ceding neural in the latter species is elongated and appears to occupy the place of two neurals; 
and it is possible that the sixth and seventh neurals of Lambe's figures were consolidated. The 
presence of the ninth pair of costals is probably an individual variation and of no classificatory 
value, as suggested by the Yale specimen oi Echmatemys wyomingensis{'Le^iAy),v!\\'ic\\ possesses 
ten pairs of costals. The very broad vertebral scutes indicate that the genus is distinct 
from Ba'ena. Mr. Lambe placed the genus provisionally among the Chelydridx, but as no 
genera of this family are known from deposits older than the Tertiary and as the type has some 



94 



FOSSIL TURTLES OF NORTH AMERICA. 



resemblances to the Ba'enida, which flourisht at that time, it seems better to refer Neurankylus 
to this family until more is known about it. 

Neurankylus eximius Lambe. 

Neurankylus eximius, Lambe, Contrib. Canad. Palaeont., lii (4 to), 1902, p. 42, fig. 7. 

The remains on which this species was based were collected by Mr. Lawrence M. Lambe 
in 1901, from Judith River deposits, Belly River series, on Red Deer River, Alberta. They 
consist of the costals of the third pair; the right fourth; the left fifth, sixth, seventh, eighth, 
and the supernumerary ninth; the most posterior neural; and the suprapygal. No peripheral 
bones were secured. The individual appears to have had a carapace 360 mm. long. The 
eighth neural is elongated and wider behind than in front. It articulates laterally with the 




Fig. 90. — Neurankylus eximius. Hinder portion of carapace of type. 
From Lambe's figure. Xj. 

c. p. 3, c. p. 4, etc., costal plates; n. 3, n. 4, etc., neural plates; spy, suprapygal. 

costals of the seventh, eighth, and ninth pairs. The posterior neural of Baena riparia artic- 
ulates with the seventh and eighth pairs of costals. The suprapygal of Neurankylus eximius 
was probably followed by a pygal. 

The vertebral scutes are relatively broad, the third being nearly twice as wide as long. 
The sides are bracket-shaped. The costo-marginal sulci evidently ran along on the peripheral 
bones. The costal scutes had relatively little height. 

Mr. Lambe states that no very decided sculpture is shown on the surface of the bones. 
Striations occur adjoining and at right angles with the sutures; elsewhere, especially near the 
proximal ends of the costals, there is some roughness, produced by small, obscure, and irregular 
depressions. On two of the costals there occur some comparatively large, concentrically 
curved groove-like markings. 

Genus THESCELUS nov. 

Carapace with an enamel-like surface, which is sculptured into raised dots and lines, the 
latter irregular in length and direction, with intervening pits and valleys. The front of the 
carapace shortened and excavated in the midline; the rear somewhat pointed. The plastron 
like that of Baena. Bridges broad, extending far forward. The buttresses feebly developt. 

Type : Thescelus insiliens Hay. 

The bridges of the members of this genus extend far forward, so that the opening for the 
head and fore legs is narrowed. The movements of the fore legs must have been a good deal 



BAENIDiS. 



95 



restricted. On the other hand, the openings for the hind legs were large. It seems probable 
that these turtles were accustomed to lying in the water in wait for passing victims and 
leaping on them and seizing them. The hinder limbs were probably large and strong. 

Quaere alium, tua quem moveant miracula, dixit 
Thescelus; utque manu jaculum fatale parabat 
Mittere, in hoc hsesit signum de marmore gestu. 

— Ovid, Mel., V, i8l. 
Thescelus insiliens sp. nov. 
Plates 24, 25. 

The basis of this species is a specimen which was collected for the American Museum of 
Natural History by Mr. Barnum Brown, in 1900, in the Laramie beds of Wyoming. The 
locality more accurately stated is on Seven Mile Creek, about 5 miles north of the Cheyenne 
River, and about 40 miles west of the town of Edgemont, South Dakota. 

The specimen is a very complete one, presenting both the carapace and the plastron. The 
carapace is in some parts, especially at the peripherals over the bridges, considerably fractured. 
Very few parts are, however, missing, and the form and the general structure can be deter- 
mined. Unfortunately, both the bone and the matrix filling the interior are very friable. 

Traces of the sutures between the costals are present and have been indicated in the figures. 
It has been found impossible to determine the boundaries of the neurals. Faint traces of the 
sutures have lead to the provisional delimitation of the nuchal bone. The first peripherals are 
probably correctly represented. It is believed also that the sutures between the various bones 
of the plastron are correctly determined, where indicated definitely. The form and extent of 
the epiplastra and entoplastron are conjectural, as no traces of the sutures can be made out. 

The form of this turtle is rather remarkable. Seen from above, the shell resembles that of 
Caretta caretta. It is broad, not greatly elevated, with a median frontal excavation for the 
neck, and narrowed behind. The plastron resembles greatly that of the species of Baena. 
It extends, however, far beyond the front of the carapace, while it fails equally as much to 
reach the hinder border of the carapace. The bones are thin. 

The length of the carapace (plate 24) in the midline is 397 mm. The first peripherals 
extend 21 mm. in front of the bottom of the anterior excavation; thus the total length is 418 mm. 
The greatest breadth, across the middle, is also 397 mm. The height above the plastron is 
140 mm., but in life it has evidently been somewhat greater. 

From the ends of the axis of greatest width the border of the carapace curves forward to 
the anterior excavation. Passing backward from the axis referred to, the border is at first 
very slightly concave to just behind the inguinal notches; then rather strongly convex for some 
distance; then again rather strongly concave; at length convex to the midline behind. The 
last concavity in the border would be over the hind legs, when extended backward. Beyond 
the sinuosities mentioned, there are no notches, scallops, nor indentations in the free borders of 
the carapace. The edge of the shell just behind the inguinal notches appears to have been 
somewhat flared upward; but this appearance may be due to some distortion. 

In the hinder region of the carapace the peripherals are about 7 mm. thick and with acute 
free borders. As the border of the carapace is followed forward, it becomes more obtuse. The 
nuchal and the first peripherals are about 9 mm. thick. There are nowhere any carinse or 
bosses on either the carapace or the plastron. 

The whole surface of the carapace is covered with a hard, enamel-like layer, like that of 
Compsemys, Glyptops, and Trtonyx. The ornamentation consists of raised dots and lines. 
The latter are sometimes straight, sometimes bent, or brancht, or anastomosing. The general 
effect is that of shagreened leather. On each side of the sutures between the costals a band of 
the surface is striated at right angles with the suture. It is from this striation, when present, 
that the position of the sutures can be made out. Near the rear of the carapace there are such 
indications of sutures as to justify the outlining of a suprapygal similar to that of Glyptops 
plicatulus. 

The anterior portion of the carapace is unusually short, the abbreviation being at the 
expense of the first costals, the anterior peripherals, and the nuchal. The form and position 
of the latter are indicated provisionally, but there seems to be sufficient evidence to show that 



q6 fossil turtles of north AMERICA. 

its anteio-posterior extent was only about 30 mm. Were the anterior excavation not present, 
the fore-and-aft extent of the nuchal would be about normal. 

The first peripheral has a fore-and-aft extent of about 43 mm. Its length, parallel with the 
border, can not be accurately determined; it was about 65 mm. From this specimen it can not 
be learned where the sutures between the costal and the peripheral bones were situated, except 
in the case of the first peripherals. However, since in both Glyptops and Ba'ena these sutures, 
over the bridges, follow the sulci between the costal and marginal scutes, it is probable that 
they do so in Thescelus. In Glyptops plicatulus, behind the bridges, the sutures rise a 
considerable distance above the epiderrtial sulci; in Ba'ena emilice, a very little above. In 
Thescelus insiliens the structure of the surface of the bone appears to indicate that behind the 
bridges the sutures are placed somewhat above the scutal sulci, and they are accordingly so 
represented provisionally. 

The number and the extent of the peripherals along the border can not be made out with 
certainty. 

The epidermal scutes and their limits are for the most part determinable. The sulci are 
narrow and shallow, but usually distinct. The first vertebral is 60 mm. long in the midline, 
concave in front, behind, and on each side. The width behind is 75 mm., but in front it is 
expanded to 98 mm. The next three vertebrals are from 90 mm. to 95 mm. wide. The exact 
limit between the fourth and the fifth can not be determined. The fifth vertebral is i lomm. wide. 

There seems to have been no nuchal scute. The first marginal on each side is very narrow, 
8 mm. to 10 mm., and extends along the free border of the carapace 30 mm. The succeeding 
marginals increase in height and length to the fourth, which is 55 mm. high and occupies 
85 mm. of the free border. The succeeding marginals retain this width to beyond the inguinal 
notch; the posterior are much narrower. There were probably paired supracaudal scutes. 

The plastron (plate 25) has a median length of 420 mm. The anterior lobe has a length of 
117 mm. The base is 170 mm. wide, but the lobe narrows forward so rapidly that at the 
crossings of the gular sulci the width is only 91 mm. The posterior lobe is no mm. long, 
168 mm. wide at the base, and 130 mm. wide at the ends of the femoro-anal sulci. The 
posterior end is broad, and occupied by a wide emargination 10 mm. deep. 

The bridge is 194 mm. wide, fore and aft. From its inner end to the border of the carapace 
is about 120 mm. 

The sutures bounding the epiplastron and the entoplastron are not demonstrable; hence 
they are represented provisionally. The thickness of the epiplastra is about 9 mm. 

There are very broad mesoplastra extending across the plastron. The width of the outer 
end of each bone is about 100 mm., being apparently a little greater on one side than on the 
other. Where the bones meet at the midline they are 54 mm. wide. These mesoplastra differ 
from those oiGlyptops in being proportionally larger and in having their median ends narrower 
than the outer. They are much like those oi Ba'ena emilta. 

The extent of the hyoplastra along the midline equals about 105 mm.; that of the hypo- 
plastra 100 mm. The anterior borders of the xiphiplastra run straight across the plastron, 
except near the border of the plastron, where they send forward on each side an angular 
process into the hypoplastron. Just behind this process the xiphiplastron is 10 mm. thick; 
near the hinder end, 6 mm. 

The intergulars and gulars of this species are much like those of Ba'ena emilia. The 
former, taken together, extend 30 mm. from side to side; 16 mm. fore and aft. The gulars are 
very large, the sulci bounding them behind meeting the midline 54 mm. behind the front of 
the plastron, and diverging with an angle of about 140°. If the entoplastron has been even 
approximately defined, the humero-pectoral sulcus falls far behind it. The fore-and-aft 
extent of the humerals along the midline is 87 mm. The sulci between the pectorals and the 
abdominals are deflected backward near the midline on each side. The pectorals occupy only 
55 mm. of the midline. The femorals are 60 mm. fore and aft; the anals 72 mm. The femoro- 
anal sulci are directed far forward as they approach the midline, exactly as in Ba'ena. 

On the bridge there are 4 large inframarginals whose boundaries have been satisfactorily 
determined. 

The buttresses of the plastron are intermediate, in extent of development, between those ot 
Glyptops and Ba'ena. 



BAENID^. 



97 



Thescelus rapiens sp. nov. 

Figs. 91, 92. 

This species is represented by a single shell, which was collected from Laramie deposits, 
at Ojo Alamo, San Juan County, New Mexico, in 1904, by Mr. Barnum Brown, of the 
American Museum of Natural History. The catalog number of the specimen is 6066. 
The shell has been damaged considerably by weathering, and lacks a portion of the carapace 
in the nuchal region, some portions of the right costals, most of the peripherals, the front of the 
plastron, and the rear of the xiphiplastrals. 

The length of the carapace must have been close to 400 mm.; the width about 375 mm. 
Apparently the shell was considerably deprest. The front of the carapace over the neck was 
excavated, but not so deeply as in T. instUens. The area occupied by the vertebral scutes 
presents a broad, shallow longitudinal channel; but in this, over the neural bones, there is a 
low ridge. The free borders of the anterior peripherals are rather obtuse. 

The sutures of the shell are obliterated, but a few of them may be traced by the fine stria- 
tions which cross them. So far as they can be made out, they are shown in the diagrammatic 




92. 




Figs. 91 and 92. — Thescelus rapiens. Carapace and plastron. Type. xj. 
91. Carapace. 92. Plastron. 

figures. The scutal areas are distinctly markt on the shell. They present various irregularities. 
The vertebrals (fig. 91) are broader than long; their dimensions are shown in the table 
on page 98. 

On the left side there is a supernumerary costal scute. This has been cut off mostly from 
the first costal proper, but to some extent from the second marginal. The fourth marginal, 
shown on the left side, has a height of 57 mm., rising somewhat on the costals. 

The plastron (fig. 92) is large. From a low ridge which joins the free border of the front 
lobe with that of the hinder lobe the bridges ascend at an angle with the remainder of the 
plastron. The axillary notch is far forward, falling about 55 mm. behind the front of the 
carapace. The opening for the head and legs is thus considerably restricted. The front lobe 
extended evidently much beyond the front of the carapace. Its length can not be determined. 

7 



98' 



FOSSIL TURTLES OK NORTH AMERICA. 



Vertebral. 


Length . 


Width. 


I 


5o± 


8i± 


2 


75 


92 


3 


81 


92 


4 


61 


92 


5 


• 


86 



The width of the base is 150 mm. The bridge is 167 mm. wide The length of the hinder lobe 

was approximately 100 mm.; the width at the base is 165 mm. It narrows rather rapidly 

backward, so that at the femoro-anal sulcus the width is 104 mm. 

There are present large mesoplastra, the boundaries of which can be pretty satisfactorily 

determined. These are about 35 mm. wide at the midline, but they expand to about 85 mm. 

at the peripherals. 

The median longitudinal sulcus runs a very irregular course, and across the femorals it 

can not be distinguisht with certainty. The humerals occupy 70 mm. of the midline; the 

_^ pectorals, about 90 mm.; the abdominals, about 35 mm.; the 

femorals, about 52 mm. The femoro-anal sulcus runs far forward 
from its starting point on the border of the plastron. Probably on 
account of weathering, the sculpture of the carapace is nearly 
obliterated, appearing only in a few spots. On the plastron it is 
more distinct. It appears to have resembled that of T . insihens 
and consists of narrow and low ridges and tubercles. Some traces 
are observed of the ridges due to the growth of the scutes. 

This species differs from T. insiltens in having the nuchal 

less deeply excavated, in having a median depression along the back, and in having the hinder 

lobe of the plastron more rapidly reduced in width backward. In T. insilietis the bridges are 

considerably wider than the base of the hinder lobe. 

Genus CHARITEMYS nov. 

A genus of Baenidae. So far as known like Thescelus, but with the axillary buttresses 
ascending to near the neural borders of the first costals. Inguinal buttresses probably ascend- 
ing on inner surfaces of the fifth and sixth costals, but not to so great a height as did the axillary 
buttresses. 

Type: Charitemys captans Hay. 

Charitemys captans sp. nov. 
Telt-figs. 93-95- 

The type of the present species is No. 6098 of the American Museum of Natural His- 
tory. It forms a part of the Cope collection of fossil reptiles and was collected in 1876, by 
Messrs. Sternberg and Isaac, in the Judith River deposits of Montana. There are present 
considerable parts of both the carapace and the plastron, but unfortunately important parts 
are missing. 

In size this species appears to have been somewhat smaller than the type of Thescelus 
insiltens, judging from the plastral bones, but of the same size, if we judge from the widths of 
6 costal bones. 

Of neurals there are portions of only two. One of these, probably the eighth, has a width 
of 44 mm. Its length can not be determined, what is regarded as the posterior end being 
broken away. On the supposed anterior end is a rounded carina. The broader end is crost 
by a sulcus, probably that between the fourth and the fifth vertebral scutes. On the under side 
are three impressions for three neural spines. The other neural is only 30 mm. wide. It 
probably belonged near the beginning of the series. 

Of the costals there are present the proximal end of the first of the left side, the right 
second, third, and sixth, and the left fourth, fifth, sixth, and seventh. Fig. 93 represents the 
second and third right costals; fig. 94, the fourth to the seventh of the left side. Of the latter 
three, more or less of the distal ends are missing. The supposed first presents difficulties. 
On the upper surface are found portions of the first and second scute areas and of the first 
costal area. The area of the first vertebral scute on this costal is only 16 mm. wide. The 
whole width of this scute could hardly have exceeded 65 mm. On the lower side is a large tri- 
angular articular scar for the axillary buttress of the plastron. This approacht within 21 
mm. of the neural border of the costal. Between the scar and the neural border is a sharp 
ridge from which appears to have been broken the rib-head of the costal. This was much 
slenderer than those of the succeeding costals. The slenderness of this rib-head was hardly to 



BAENID^. 



99 



have been expected. There is present a portion of one plastral buttress, the length of which is 
72 mm. ; but this has the appearance of being the inguinal buttress. 

The second costal (fig. 93) has a length of 142 mm., a width of 54 mm. at the costo-vertebral 
sulcus, and of 60 mm. at the distal end. The proximal end is crost by the sulcus bounding 
laterally the second vertebral. This had a width of about no mm. Anteriorly it narrowed 
considerably. Its anterior end occupied only 18 mm. on the first costal plate. The distal end 
of the costal is crost by the costo-marginal sulci, a condition showing that the fourth and fifth 
marginal scutes overlapt on the costal bone. 

The third costal plate (fig. 93) is slightly narrower than the second at the proximal end and 
wider than the latter at the distal end. The fifth and sixth marginal scutes overlapt slightly 
on the distal end. The proximal end was occupied by a part of the second and a small part of 
the third vertebral scutes. The fourth left costal (fig. 94) is 48 mm. wide at the costo-vertebral 
sulcus; 66 mm. at the distal end. That portion of the third vertebral scute on the proximal 
end of this costal is 48 mm. wide. The costo-marginal sulcus skirts along the distal end of the 






Figs. g^-g^.—Charitemys captans. Costal bones and plastron of type. Xj. 

93. Second and third right costals, the second on the right. 94. Fourth to seventh costals of left side. 

95. Plastron considerably restored. 

bone. The fourth and fifth costals are each 45 mm. wide. Of the seventh there is present a 
fragment 46 mm. long and 31 mm. wide at the sulcus. The rib-heads of the fifth and sixth 
costals have a diameter of about 6 mm. No trace of the articulation for the inguinal buttress 
appears on the parts preserved of the fifth and sixth costals. It is evident, therefore, that this 
buttress did not ascend to as high a point as did the axillary. From the form of the sutural 
border of the supposed inguinal buttress it is believed that the latter was articulated to the 
fifth and sixth at their junction. 

Of the plastron (fig. 95) there are present a fragment of the left epiplastron, a large part 
of the right hyoplastron, the left hypoplastron, and a portion of the free border of the right 
xiphiplastron. These are represented in the diagrammatic figure. 

That this turtle possest a mesoplastron is evident; otherwise, the bridges would have been 
only about 100 mm. wide, about one-half as wide as the costals spanned by the two buttresses 
of one side. No part of the mesoplastrals appears to be included among the bones present. 
Their antero-posterior width is only conjectural. 



lOO FOSSIL TURTLES OF NORTH AMERICA. 

The piece of epiplastron present is 9 mm. thick. The gulo-humeral sulcus crosses the 
hinder end as in Glyptops and Ba'ena. 

The length of the hyoplastron, from the epiplastral suture to the mesoplastron, is 120 mm. 
The width of the anterior lobe was about 142 mm. The distance from the axillary notch to 
the mesoplastron measured very close to 50 mm. The thickness of the bone at the entoplastral 
suture is 6 mm. The free border in front of the axillary notch is subacute. Most of the border 
which rose to meet the peripherals is broken away. A portion of the sulcus between the 
abdominal scute and the anterior inframarginal is present. 

The length of the hypoplastral at the midline is 90 mm.; the width at the base of the 
hinder lobe, 80 mm.; the width from the midline to the union with the bridge peripherals, 
130 mm. A portion of the outer end of the bone is missing, but a section of the sulcus is seen 
starting forward from the inguinal notch and section of another sulcus between the hinder 
inframarginal and the contiguous marginals. The hinder inframarginal has a width of about 
45 mm. Its anterior end appears to have extended on the mesoplastron. 

The fragment of xiphiplastral is 53 mm. long. It shows the free border. This is subacute, 
and from it the bone thickens soon to 10 mm. No portion of the upper surface was covered 
with scutes. On the lower surface the femoro-anal sulcus crost the bone about 30 mm. behind 
the suture with the hypoplastron. The form of the hinder border of the lobe can not be 
determined. 

Of the skull there is present the pedicel of the left quadrate. The condyle for the lower 
jaw is concave, 1 1 mm. from side to side, and less than 5 mm. antero-posteriorly. At the inner 
side of this condyle there ascends toward the lower end of the parietal plate a sharp ridge. The 
rough surface for the pterygoid lacks 8 mm. of reaching the condyle, a fact that shows that 
this genus did not belong to the Pleurodira. 

The upper surface of the carapace was more or less uneven, especially along the midline. 
All the articular borders of the bones are striated perpendicularly to the sutures. Besides this, 
there is a delicate pitting of the surface which gives the effect of leather. The lower halves 
of the costals are markt by coarse ridges, which have been produced during the growth of the 
costal scutes. 

The plastral bones have all the sutures conspicuously markt by striae, which run at right 
angles with the sutures. The whole surface is occupied by a fine network of delicate lines. 

Genus POLYTHORAX Cope. 

An insufficiently known genus of uncertain position. Plastron suturally united with the 
carapace; furnisht with the usual scutes, besides intergulars and interhumerals. Lower jaw 
with narrow ramus; the triturating surface bounded outwardly by a sharp margin; the 
symphysis short. 

Type: Polythorax missurtensis Cope. 

This genus is arranged provisionally among the Baenidae; but it is probable that it and 
Archceochelys Lydekker belong to a distinct family. 

Polythorax missuriensis Cope. 

Polythorax missuriensis, CoPE, Proc. Acad. Nat. Sci. Phiia. 1876, p. 258; Bull. U. S. Geo), and Geog. 
Surv. Terrs., Ill, 1877, p. 573. — Hay, Bibliog. and Cat. Yoss. Ven. N. A., 1902, p. 438. — Hatcher, 
Bull. U. S. Geol. Surv. 257, 1905, p. 77. 

It is not at present known what has become of the type of this species. It was found in the 
Judith River deposits of Montana, in 1876. The plastron appears to have been pretty complete, 
but we are not told how much of the carapace was secured. No part of the species has ever 
been figured. 

The plastron had a total length of 183 mm.; hence the individual was not a large one, 
perhaps attaining about the size of our Trachemys elegans. The anterior lobe had a length of 
49 mm. The bridge was 76 mm. wide and as long. The anterior lobe is stated to have been 
narrower at the base than the bridge. We must conclude therefore that this lobe was not one- 
third as wide as the carapace. Its anterior extremity was rounded. The width of the base of 



BAENID^.. lOI 

the hinder lobe is not given, but its posterior extremity was 35 mm. wide, truncated, and 
with rounded angles. It was shorter than the anterior lobe. Its thickness in the inguinal 
region was 10 mm. 

The surface of the plastron was obsoietely, but coarsely, rugose; roughest in front, where 
the sculpture consisted of short, raised lines irregularly disposed. 

The intergulars were distinct. These were followed by a pair of interhumerals, which were 
longer than wide and crowded the humerals away from each other, and they seem to have 
extended themselves backward between the pectorals likewise. The pectoro-humeral sulcus 
appears to have been advanced well forward. Cope states that it was impossible to determine 
whether or not "intermarginal " scutes were present, and that if they existed their position was 
quite external. It is probable that by "intermarginals" was meant inframarginals. 

The carapace is stated to have possest an openly dentate posterior border. The surface 
was irregularly swollen, especially along the margins of the vertebral scutes. The latter were 
wide; the marginals are said to be narrow, by which is probably meant that they rose but a 
short distance from the free margins. 

The description of this species given by Cope indicates that it was related to Ba'ena rather 
than to Adocus. The thoro co-ossification of the bones, so that the presence of mesoplastrals 
could not be proved or disproved, the uneven surfaces of the shell, the notcht border of the 
carapace, all point toward Ba'ena. At the same time, the presence of the interhumerals 
marks it off as different from all North American turtles hitherto described. Archceochelys 
(Lydekker, Cat. Foss. Rept., pt. in, 1889, p. 219), from the Wealden of England, has the 
humerals separated by what has been regarded as an intergular, but which is quite as likel\' 
an interhumeral. Behind this come in succession an interpectoral, an interabdominai. 
and an interfemoral. The latter extends itself backward between the anals also. That is, the 
scutes which usually join in pairs along the median line are here separated the length of the 
plastron by a series supposed to be azygous. These median scutes in both Polythorax and 
Archceochelys are probably homologous with the median series o( Dermochelys. 

Mr. Lydekker places his genus provisionally in the Amphichelydia. 

Genus NAOMICHELYS nov. 

A genus known only from the entoplastron. Outer surface ornamented with elevations 
resembling small shot. A long narrow scute (intergular or interhumeral) occupies most of the 
length of the bone. Gulars ? and humerals ? present. 

Type: N aomtchelys speciosci Hay. 

The relationships of this genus are not certain. It may belong among the Pleurosternidx 
rather than among the Baenidx. It is here put in the vicinity o{ Polythorax. 

Naomichelys speciosa sp. nov. 

Plate 40, figs. 2, 5. 

The only portion of this species at present known is an entoplastron which was collected 
in 1904, by Mr. Barnum Brown, of the American Museum of Natural History. It was secured 
in the Upper Jurassic, Morrison beds, 25 miles east of Pryor, Montana. The catalog number 
is 6136. The bone is complete, except that the extreme anterior end is broken away. The bone 
is 85 mm. long, and was originally about 10 mm. longer. The width is 78 mm. The thickness 
is quite uniformly close to 7 mm. Where the bone joined the epiplastra the upper surface 
extends out a little farther than the lower. The hyoplastrals overlapt extensively the ento- 
plastron, as may be seen from plate 42, fig. 3. Fig. 2 of the same plate shows the scutes and 
the ornamentation of the inferior surface. Five scutes are represented in the bone. There 
is a long median scute which narrows forward, as well as backward. It seems probable that 
anteriorly it did not extend beyond the bone. This scute may be the intergular which was 
crowded backward by the gulars as in Chelodina novceguince (Boulenger, Cat. Chelonians. 
pi. vi), or it is possibly an interhumeral or an interpectoral. Attention is called to Cope's 
Polythorax and Lydekker's Archceochelys. 

On each side of the scute just described is another which may be either an mtergular or a 
gular. Behind this is a large scute which is assumed to be the humeral. 



I02 FOSSIL TURTLES OF NORTH AMERICA. 

The surface of the bone is covered with rounded elevations which resemble small bird shot. 
There are about eight in a line lo mm. long. The basis of each elevation is often of less 
diameter than the body of it. Many of them are broken off near the surface of the bone, 
leaving circular scars. Along the edges of the bone which joined the hyoplastra there is a 
narrow border nearly free from the pustules. 

This turtle differed from Polythorax missuriensis in the character of the ornamentation, 
this consisting in the latter species of short raised lines. In that species, too, the pectoro- 
humeral sulcus appears to have been pushed well forward. In the species here described 
there is no trace of the presence of this scute. 

Superfamily PLEURODIRA Cope. 

Thecophorous turtles having a carapace composed of costals and peripheral bones and 
usually a series of neurals and a plastron in which the epiplastra are in contact with the hyo- 
plastra. Mesoplastra present or absent. Intergular scutes developt, the inframarginals 
wanting. Temporal roof of the skull varying from nearly complete to nearly obsolete. Ptery- 
goids not extending backward between the quadrates and the basisphenoid; broad, with the 
outer border uprolled. Neck bending sideways; not capable of being withdrawn between the 
scapulae. Ilia suturally joined to the eighth costals; the pubes and the ischia, to the xiphi- 
plastra. 

The living Pleurodira are divided by Boulenger into 2 families, the Pelomedusidae and the 
Chelydidae. About 30 species are known. None of these have had the anterior limbs trans- 
formed into flippers, like those of the Cheloniidx. The geographical distribution of the living 
species is illustrated by fig. 15, on page 34. The earliest turtles certainly known to belong to 
this superfamily occur in the Upper Cretaceous of North America. Cope referred these to the 
Pelomedusidae; but the present writer, following Baur, accepts for them the family Bothremy- 
didae. So far as is known, no species of the superfamily lived in North America after the end 
of the Upper Cretaceous. 

FamUy BOTHREMYDID.ffi; Baur. 

Extinct pleurodire turtles having the skull probably extensively rooft over in the temporal 
region. Vomer present. Triturating surfaces of the jaws, upper and lower, broad and deeply 
excavated. Shell as in the Pelomedusidae, with small mesoplastra. 

Baur was the author who proposed this family, making it include Bothremy s and Taphro- 
sphys. Cope had arranged these genera under the Podocnemididae. To the present writer 
it appears that the presence of a vomer, but still more the extraordinary excavations found 
in the jaws, upper and lower, are sufficient to set off Bothremys as a member of a distinct family. 
With it must go for the present Taphrosphys. 

Key to the Genera. 
A. Known from skull only: 

Each side of jaws, upper and lower, with a deep pit Bothremys 

A A. Known from shell only: 

1. Nuchal bone not shortened; free borders of peripherals acute Taphrosphys 

2. Nuchal short and broad; free borders of peripheral obtuse Amhlypeza 

3. Only the xiphiplastron known; the ischiadic scar extending to the midline Natadochelys 

Genus BOTHREMYS Leidy. 

Vomer well developt, not separating the palatines. Choanae behind the centers of the 
orbits. The nasal passages underfloored by the surrounding bones. Crushing surfaces of jaws 
broad and occupying portions of the maxilla and of the palatines; the excavation contracting 
to a pit in each. Lower jaw with the dentaries co-ossified. Shell unknown. 

Type: Bothremys cookt Leidy. 

It has been suspected that the skull represented by the type of Bothrem\s is that of some 
species of Taphrosphys, all the species of which are known only from shells. This is entirely 
possible, but nothing is to be gained at present by reducing Taphrosphys to a synonym of 
Bothremys. 



BOTHREMYDID^. 

Bothremys cooki Leidy. 
Plate 23, figs. I, 3; text-figs. 96, 97. 



103 



Bothremys cookt, Leidy, Smitlison. Contrib. Knovvl., xiv, art. vi, 1865, pp. no, 120, plate xviii, figs. 
4-8.— Cope, Cook'.s Geol. New Jersey, 1868 (1869), p. 735; Amer. Naturalist, iii, 1869, p. 89; 
Ext. Batrach., Reptilia, Aves N. A., 1870, p. 157; Vert. Cret. Form. West, 1875, p. 263.— Maack, 
Palaeontograph., .xviii, 1869, p. 280.— Baur, Ann. and Mag. Nat. Hist. (6), iv, 1889, p. 38.— Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 

The skull which has furnisht all that we know of this species is a most extraordinary one. 
It was found in the lower bed of greensand, belonging to the upper Cretaceous, near Barnes- 
boro, Gloucester County, New Jersey, and is now in the geological collection of Rutger's 
College, New Brunswick, New Jersey, where the writer has been permitted to examine it. It 
was fully described and figured by Leidy in his original description. His figures are stated 
to be of the size of nature, but they are really somewhat reduced. Plate 23, figs. 2, 3, of the 
present work is reproduced from drawings belonging to the U. S. Geological Survey. These 
were prepared in 1888 for Dr. George Baur, who was then preparing to monograph the fossil 
turtles. The one showing the lower surface of the skull differs from that of Dr. Leidy in 
indicating the positions of the sutures. It will be observed that in this drawing the missing 
quadrate regions are restored in outline. 

The skull, from the tip of the snout to the occipital condyle, had originally a length of 
clo,se to 70 mm. The width at the hinder end of the maxillae is 70 mm. From the latter point 





Figs. 96 and 97. — Bothremys cooki. Skull of type. Xjj. 
96. .Seen from above. 97. Seen from right side. 

the outline of the skull rounds rapidly to near the end of the snout. Just before this is reacht 
the curves change somewhat, so that the snout is slightly prolonged. The skull is flat above 
(text-figs. 96, 97) there being a slight descent from the orbits forward. The interorbital 
space is 17 mm. wide. The eyes lookt strongly upward. Both diameters of the orbits 
measure 14 mm. From the upper borders of the orbits the sides of the face sloped downward 
and outward with a moderate curvature. The outline of the upper jaw, seen from the side, 
is very convex. The nasals are absent. Whether or not the temporal region was widely 
rooft over is uncertain, but it is probable that such was the case. 

A view of the lower surface of the skull shows many interesting features. The premaxillae 
are large, extending backward a distance of 18 mm. Behind these comes the well-developt 
vomer, which presents feeble palatine plates, to aid in underflooring the nasal passages. 
The length of the vomer as seen from below is 15 mm. It lacks much of reaching the 
pterygoids. The palatines meet the vomer in advance of the choanae. The anterior borders of 
the choanae are placed 24 mm. behind the tip of the snout. These choanx lie in a vaulted 
excavation, which, beginning on the premaxillae and expanding backward, reaches to the post- 
palatine foramina, being shallow in front of the choanae. The excavation is bounded on each 
side by a prominent tootht ridge, the inner boundary of the triturating surface of the jaw. 
The pterygoids meet along the midline a distance of only 7 mm. As in the Pleurodira gener- 



I04 FOSSIL TURTLES OF NORTH AMERICA. 

ally, the pterygoids are wide, and the outer border is uprolled in a scroll-like manner. The 
basisphenoid, most of which is present, is large, the width being 13 mm. 

The most striking feature of the skull is presented by the triturating surfaces of the upper 
jaws. On the premaxillae they are very narrow. Backward each expands rapidly and occupies 
most of both the maxilla and the palatine. The greatest width is 24 mm. Each, instead of 
being flat, is deeply excavated. At the suture between the maxilla and the palatine the exca- 
vation contracts into a circular pit which rises in the maxilla to the height of the floor of the 
orbit. The walls inclosing this pit are smooth. The remainder of the triturating surface is 
perforated by openings for blood-vessels. 

The lower jaw shows little else than the co-ossified dentaries. These are of very solid 
construction. The jaw as a whole is thin and pointed in front, but the coronoid processes rise 
to a height of 27 mm. The symphysis has a length of 20 mm. The triturating surfaces are as 
remarkable as those of the upper jaw. Each may be described as containing a deep pit, 
situated at the hinder end of the dentary and opening forward and upward, trumpet-like, on 
the upper surface of the dentary. The trumpet-shaped mouth extends forward to near the tip 
of the jaw. It is bounded outwardly by the cutting-edge of the jaw; inwardly by a ridge, which 
rising at the tip of the jaw, runs backward and upward, increasing in height to the coronoid 
process, along the inner border of the ramus. 

The purpose of the pit-like excavations in the jaws, upper and lower, is problematical. 
In speaking of the pit in the upper jaw Leidy said that it did not appear like an alveolus for a 
tooth, but that it may have accommodated a corneous tooth-like process springing from the 
corresponding hollow of the lower jaw. Baur thought that the pits lookt much like the alveoli 
of large tusk-like teeth. 

It does not appear probable that there were any teeth in this turtle. It seems far more 
probable that both jaws were covered with plates of horn, as are those of all other known 
turtles. The whole construction of the skull of Bothremys indicates that it was accustomed to 
crush hard objects as food. Probably these objects were of sucK a nature that economy of 
force demanded that they should be brought to a particular spot on the jaw for crushing. To 
provide for the rapid reproduction of the horn beneath these areas for crushing, these pits 
became developt in a way analogous to the human "nail-bed." 

Genus TAPHROSPHYS Cope. 
Prochonias CoPE. 

A genus of pleurodirid turtles known only from the shell. Carapace with y neurals, the 
costals of the seventh and eighth pairs meeting their fellows at the midline; a large suprapygal; 
and 1 1 pairs of peripherals, the posterior thin and with acute free borders. No nuchal scute. 
Plastron with 1 1 bones, the mesoplastrals small and well out on the bridges. A single intergular 
almost wholly confined to the entoplastron. Hinder lobe with large notch. Large pits in the 
first and the fifth costals for the axillary and inguinal buttresses. Ilium firmly articulated with 
the carapace at the junction of the seventh and eighth costals. Ischium and pubis articulated 
to the xiphiplastron. 

Type: Platemys sulcatus Leidy. 

In Cook's Geology of New Jersey, 1868 (1869), page 735, Cope mentions the generic name 
Taphrosphys in connection with 3 specific names, as follows: T. molops, T. princeps, and 
T. sulcatus. The first two had not yet been described, the last was Leidy's Platemys sulcatus. 
In the April (1869) number of the American Naturalist, Cope again mentions the name 
Taphrosphys, this time in connection with molops only, while to the new genus, Prochonias, 
were referred the species P. sulcatus, P. strenuus, and P. princeps. Of these again none had 
yet been described except P. sulcatus (Leidy). The latter therefore is the type both of 
Taphrosphys and Prochonias. Which of these names has precedence depends on which was 
issued first to the public, the April number of the American Naturalist or Cook's Geology of 
New Jersey. Investigations not wholly satisfactory seem to show that the latter was first 
publisht, probably some time about the first of March, 1869. This conclusion enables us to 



BOTHREMYDID^. IO5 

retain the name to which Cope finally referred all the species named above and some others. 
In his monograph of 1869 and 1870, he described all his species and made Prochonias a 
subgenus of 7aphrosphys. Here T . molops was regarded as the type of Taphrosphys. 

All the species known to belong to this genus are represented by fragmentary individuals, 
but these furnish us the means of obtaining a pretty clear idea pf the structure of the carapace 
and the plastron. Nothing is known regarding the skull, unless it be that the skull known as 
Bothremys cookt belongs to a species generically identical with Taphrosphys. Of the limbs 
extremely little is known. Evidently the genus belonged to the Pleurodira and was not far 
removed from Podocnemis. There were 8 pairs of costal bones, the last two pairs meeting on 
the midline. The nuchal bone is large and expanded behind. There were seven neurals, the 
first large, the last small. There were 1 1 pairs of peripherals, a suprapypal and a pygal. The 
peripherals of the hinder part of the carapace were thin and acute. Those of the anterior 
portion of the bridge, the fourth and fifth, appear to have had the free border thickened and 
rounded or with faces at right angles; while those succeeding them had the free borders acute 
and the faces, upper and lower, meeting at an angle less than right. 

On the inferior side of the first costal was a deep pit for the reception of the axillary buttress; 
on the fifth was another pit for the inguinal buttress. An extensive excavation, partly in 
the seventh costal and partly in the eighth, received the upper end of the ilium. This excava- 
tion occupied more than a half of the length of these costals. 

The upper surface of the carapacial bones is markt by irregular grooves, which anastomose 
more or less and divide it into areas differing in size and form in the different species and on 
diflFerent parts of the same individual. The sulci are shallow and sometimes obscure. Evi- 
dently, the epidermis was thin. There was no nuchal scute. The vertebrals were rather 
broad. The marginals did not overlap on the costal bones. 

The plastron was well developt, but the anterior lobe was short and broad, and rounded. 
Strong buttresses rose from the plastron to articulate with the carapace. On the xiphiplastrals 
were well-developt articulatory surfaces for union with the ischia and the pubes. The posterior 
notch was large and rounded. As stated by Cope, and as shown by the borders of various 
hyoplastra and hypoplastra, there were small triangular mesoplastra, which occupied each a 
position on its bridge. The free borders of the anterior lobe were mostly obtuse; those of the 
hinder lobe were mostly acute. The inferior surface is sculptured like the carapace; but 
often the markings are obscure. The scutes of the anterior lobe are not all satisfactorily 
determined. There was a large intergular that occupied a considerable part of the entoplastron. 
Apparently, as shown in the figure of the anterior lobe of 7". mo/o /ix (fig. 116), this was bounded 
in front by a sulcus across the entoplastron, thus permitting the gulars to meet each other at the 
midline. It is possible that the intergular extends to the front of the lobe, as represented in 
fig. 106, and that the gulars do not join each other. The humerals lie on the outer ends of the 
epiplastra, overlapping on the hyoplastra. The arrangement of the other plastral scutes may be 
seen from the figures. Those on the bridges are not known. 

//'. Species with shell having an even surface, except that it bears a network of vascular grooves, 
a'. Surface of shell usually with a close network of rather broad grooves. 

1. A large species with bones of moderate thickness; the fourth vertebral scute 

nearly a half wider than long sulcatus 

2. A species of moderate size; second and fourth vertebral scutes little wider 

than long longinuchus 

3. A small species with thin bones; second vertebral scute twice as wide as long; 

the fourth probably as wide as the second leshanus 

4. A large species with thick bones; front of plastron broad, truncated, or concave 

on each side of the thickened epiplastral symphysis strenuus 

5. A large species with bones of moderate thickness; front of plastron rounded; 

the first and third vertebral scutes about one-half wider than long molops 

(?. Surface with thread-like grooves which form large meshes. 

A large species with thick bones; entoplastron broader than long, its postero- 
lateral sides excavated i/ar« 

A"^. Surface of shell coarsely sculptured like that of the Trionychidae nodosus 



ta5 



FOSSII. TURTLES OF NORTH AMERICA. 

Taphrosphys sulcatus L.eidy. 
Teit-figs. 98-100. 



Pliitemys sulcatus, Leidy, Proc. Acad. Nat. Sci. Phila., viii, 1856, p. 303; Smithson. Contrib. Know!., 

XIV, an. VI, 1865, pp. log, 120, plate xix, fig. 4. — Maack, Palseontographica, xviii, 1869, p. 281. 
Taphrosphys sulcatus, CoPE, Cook's Geol. New Jersey, t868 (1869), p. 735; Ext. Batrach., Reptilia, 

Aves N. A., 1870, pp. 159, 164, text-figs., 45, 45 bis; Vert. Cret. Form. West, 1875, p. 264. — Hay, 

Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 439. 
Prochonias sulcatus. Cope, Atner. Naturalist, iii, 1869, pp. 89, 90; Ext. Batrach., etc., p. 165, line 8, 

plate xi, fig. 2. 

As has occurred too often in the history of paleontology, the present species was based on 
very meager materials. These consisted of 3 peripheral bones, regarded as the fifth, sixth, and 
seventh, and a xiphiplastral. Only the peripherals were figured. These were large, measuring 
altogether 8 inches along the free border. They came from the Cretaceous greensand at Tinton 
Falls, Monmouth County, New Jersey, and are preserved in the geological collection of Rutgers 
College, New Brunswick, New Jersey. Leidy's description of these bones is very brief. Each 
bone has two faces, an upper and a lower, the lower broad and flat, the upper inclining toward 
it at an angle of nearly 45°, the two meeting along an acute margin. The fifth is 54 mm. long on 




99. 



Figs. 98 and 99. — Taphrosphys sulcatus. No. 1468 A. M. N. H. 
98. Section of seventh peripheral of type. X^. 99. Rear of carapace. Xj. 

the free border; the sixth, 60 mm.; the seventh, 76 mm. The sixth rises from the free border to 
the costal border, 69 mm.; the seventh, 70 mm. The anterior end of the seventh is much thick- 
ened and has afforded an articulation with the inguinal buttress. In front of this articulation 
the bone is somewhat excavated by the sternal chamber. The hinder end of this peripheral is 
thin, not exceeding 14 mm. (fig. 98). The free borders of all these peripherals are acute. 
The superior surface is ornamented by a close articulation of grooves. Fig. 98 represents a 
section along the sulcus between the marginal scutes that overlapt this bone. The piece of 
xiphiplastron displayed the scar for union with the pelvis. 

With this species Cope identified a specimen which he obtained from the upper greensand 
bed at Barnesboro, Gloucester County, New Jersey. This specimen furnisht him the three 
hinder pairs of costal plates, the suprapygal, the pygal, and a number of the hinder peripherals. 
There are present also portions of two bridge peripherals and some fragments of other costals. 
There appears to be no reason for doubting the correctness of Cope's identification. This 
specimen (figs. 99, 100) is now in the American Museum and has the catalog number 1468. 
It now lacks all the peripherals that Cope figured, except one. According to his figure. Cope 
lackt the eleventh peripheral. The one now present was certainly in Cope's hands, having 
his marks on it; and yet, after careful examination, that bone is found to fit in the place of the 



BOTHREMYDID^. IO7 

light eleventh peripheral and nowhere else. With it is connected a portion of the pygal. The 
proximal half of the left sixth costal is now missing. On the other hand, the distal end of the 
right seventh costal has been found and included in the figure. 

The individual was a large one, the length of the carapace being estimated at 650 mm. 
Cope states that his figure is one-third the natural size, but in reality it is in width only a little 
more than twenty-two hundredths of the original. As regards the length of his figure, it is 
much foreshortened. 

As in the other species, the costals of the last two pairs (fig. 99) meet at the midline. The 
eighth neural was not developt and the seventh was short. The sixth costals are 66 mm. wide 
at their distal ends; the seventh, 70 mm., the eighth, 54 mm. The sixth is 9 mm. thick where 
it joined the neural; 5 mm. at the distal end. 

The suprapygal, described by Cope under the name of pygal, is triangular, pointed above, 
83 mm. long and 99 mm. wide behind. The eleventh peripheral measures 72 mm. along the free 
border and is 65 mm. high. The free edge is acute. It is slightly thicker at the hinder end than 
in front, being 10 mm. posteriorly. 

Fragments of two bridge peripherals are present. One, probably belonging near the 
hinder end of the bridge, has the two faces meeting with an angle of about 50 degrees between 




Fig. 100. — Taphrosphys sulcatus. Under side of rear of carapace. X^. No. 1468 A. M. N. H. 

AA, excavated area for ilium; x, sacral rib. 

them at,one end, probably the anterior. At the other end the faces meet at an angle of about 
30 mm., the free border being acute. The other fragment has the two faces meeting at an angle 
of about 90°. This bone probably belonged near the front end of the bridge. 

As Cope states, the sculpture of the upper surface of the carapace is coarsely reticulate, 
tending to enclose areas longitudinal with the costals toward their middle and distal portions, 
while that of the peripherals is closer. The sulci are shallow and narrow. The fourth vertebral 
scute was about no mm. long and 154 mm. wide; the fifth was no mm. long, 162 mm. wide, 
only 50 mm. anteriorly. Its lateral extremities are sharply angled. The costo-marginal sulci, 
so far as they are represented, are confined to the peripherals. 

On the inferior surface of the carapace (fig. 100) we find, excavated partly in the seventh, 
partly in the eighth costals, a large pit, 78 mm. long and 28 mm. wide, for the reception of the 
upper end of the ilium. The pit is bounded anteriorly by a sharp ridge proceeding from the 
rib-head of the seventh costal. This ridge is highest at the upper end, lowest in the middle. 
Behind, the pit is bounded by a low rough ridge running along the middle of the eighth costal. 
Both the costals are much thickened at the lower end of the pit. The upper end of the pit is 
inclosed in front by a low ridge derived from the base of the rib-head of each costal; behind, 
by a distinct squarish bone, which is to be regarded as the tenth dorsal rib, corresponding to the 



io8 



KOSSII. TURTi.ES OF NORTH AMERICA. 



enlarged extremity of the tenth dorsal rib of the Cryptodira. On its hinder angle is a broken 
process, apparently the base of the rib-head. The distal end of this bone abutted squarely 
against the ilium. IJehind this squarish bone is an irregular and rough excavation in the 
eighth costal, which seems to have received another bone, probably the first sacral rib. Behind 
the rough surface just mentioned is another, lying partly on the anterior border of the suprapy- 
gal; and this may have supported the second sacral rib, not yet lost in these early Pleurodira. 

On the contiguous ends of the seventh and the eighth costals, in the midline, are j rough 
articular surfaces which were in contact with the neural arches of three vertebrae. Cope speaks 
of these as having been in contact with "rudimental and inferiorly placed vertebral pieces." 
It seems evident that the rib-head of the eighth costal was connected with the most anterior; 
the rib-head of the tenth rib with the second; while the first sacral rib-head joined the third. 

The portion of the xiphiplastron present shows this part of the shell to have been thinner 
than in T. molops. The thickness at the hypoxiphiplastral suture is 7 mm. The edge of the 
bone at the bottom of the posterior notch is present. This edge is acute, while from it the bone 
thickens to only 9 mm. The scar for the pubis is somewhat elongated, 46 mm. long and 9 mm. 
wide; therefore, much narrower than in T. molops. On the inferior surface is seen a distinct 
reticulate sculpture of moderate closeness. 

No. 1469 of the American Museum, a part of the Cope collection, is labeled by Cope as 
having been found at Barnesboro, New Jersey, in 1869; but it has not been identified as any 
one of those mentioned in his monograph so often quoted here. The left second costal bone is 
39 mm. wide at the middle of the length and 8 mm. thick. The third costal is 49 mm. wide at the 
middle of its length. Besides these costals, there are present portions of the three posterior of 
the right side. These agree with those of No. 1468 described above. Attacht to the sixth 
costal is the sixth neural. It is hexagonal, 35 mm. long, 36 mm. wide, and 8 mm. thick. The 
epidermal scute areas also are like those of number 1468. The lateral apex of the second 
vertebral is 67 mm. from the neural border of the costal. Most of the right hypoplastron is 
preserved. The length at the midline is about 105 mm.; the width at the abdomino-femoral 
sulcus 130 mm.; along the hyohypoplastral suture, 100 mm. The bone is 8 mm. thick at the 
anterior inner angle; 6 mm. at the hypoxiphiplastral suture. 

This species differs from T . longtnuchiis in having the suprapygal wider than long and in 
having the fourth vertebral scute relatively much wider. 

Taphrosphys longinuchus Cope. 

Test-figs. lOl, 102. 

Taphrosphys (Proihonins) Inngimichus, CoPE, Ext. I'atrach., Reptilia, Aves N. A., 1870, p. 159. 
Taphrosphys longinuchus. Cope, op. cit., p. 162; Vert. Cret. Form. West, 1875, p. 263. — Hay, Bibliog. 
and Cat. Foss. Vert. N. A., iqo2, p. +58. 

Cope stated in his description of this turtle that it had been obtained from the excavations 
of David Haines, New Jersey. The label accompanying the specimen, now number 1 1^5 of the 
American Museum of Natural History, informs us that the locality was Medford, which is in 

Burlington County. The level is stated by Cope in his Vertebrata 
of the Cretaceous Formations, page 263, as being "Greensand 
No. 5," which would be the upper bed of Cretaceous greensand. 
The type specimen furnishes a large portion of the carapace 
and of the plastron, but it was much fractured. Fig. 101 repre- 
sents the restored carapace; fig. 102 the restored plastron. A con- 
siderable number of other fragments remain, but can not be fitted 
to their places. 

The species was one of moderate size and one whose shell 
was of rather light construction. The length of the carapace (fig. 
101) was close to 415 mm.; the width about 390 mm. The 
form was deprest and convex in all directions. Only the eighth peripheral shows any tendency 
toward upward flaring. Only 3 neurals have been preserved — the fourth, fifth, and seventh. 
The forms of most of the others are indicated by the proximal ends of the contiguous costals. 
The dimensions, so far as determinable, are given in the accompanying table. 



Neural. 


Length. 


Width. 




48 






34 






35 






35 


16 




3» 


22 




26 


22 


7 


21 


20 



BOTHREMYDID^. 



109 



The borders of the fourth and fifth neurals are 8 mm. thick. On the under side of each 
is attacht the neural arch of the corresponding vertebra. The eighth neural was not developt 
and the costals of the seventh and eighth pairs met at the midline. The ninth and tenth dorsal 
vertebrae and the first sacral appear to have had their arches articulated with the inferior 
surface of the seventh and eighth costals at their junction. The accompanying table gives the 
dimensions of the three posterior neurals. 

The nuchal bone is urn-shaped, 90 mm. long, 43 mm. wide in front, 86 mm. across the 
widest part, and 10 mm. thick. Its free border is acute. The first peripheral measures 58 mm. 

along its free border; the second, 53 mm. The first appears to 
have been about 60 mm. high, measured at the suture with the 
second. The free border of these two peripherals is subacute. 
The greatest thickness of the second, at the distal end, is 12 mm. 
On the right side most of the peripherals are wanting from the 
second to the eighth (exclusive of both); all are missing behind the 
second on the left side, except one, probably the sixth. The upper 
and lower faces of this sixth meet at the acute free border at an 
angle of about 45°. This border is 45 mm. long and from this the bone rises 56 mm. to the 
costals. In the restoration (fig. loi), this bone has been omitted from its supposed place. 
The lower face of the bone, that proceeding to the plastron, is mostly missing. 



Neural. 


Length . 


Height. 1 
67 


8 


66 


9 


57 


58 


10 


5° 


49 




Fig. \o\.^Taphrosphys longinuchus. Carapace of the type. Xj. The stippled areas 

represent the known bones. 

All of the peripherals have acute free borders. Of the eighth, that portion to which the 
inguinal buttress was attacht is broken away. From the free border each of these bones 
thickens on the under side to half its height, then becomes gradually thinner. 

The suprapygal is triangular, 62 mm. long and 60 mm. wide posteriorly. Evidently it 
articulated on each side with the eleventh peripheral and medially with the pygal. 



no 



FOSSIL TURTLES OK NORTH AMERICA. 



VertebraL 


Length. 


Width. 


, 


75 


8o 


2 


75 


77 


3 


75 


9° 


4 


75 


86 


s 




no 



The fore-and-aft width of the first costal is 64 mm. at the proximal end; its greatest width 
was about 90 mm. Its length is estimated at 120 mm. On the lower side, at the distal end, is a 
deep triangular excavation, 40 mm. long, for the axillary buttress. From it a broad ridge 
ascends to the rib-head of the costal. In front of the ridge, along its proximal third or more, 
is another ridge, sharper and more prominent, representing the first rib. 

The fifth costal is 6 mm. thick at its distal end. On the under surface of the distal end is an 

excavation for the inguinal buttress, a groove ascending about 60 mm. above the peripheral 

border and 6 mm. wide. It is deepest at the upper end, becoming very shallow at the lower end. 

The seventh and the eighth costals are modified for close articulation with the ilium. On 

the seventh the thickening produced by the rib proper lies near the hinder border of the bone. 

The hinder part of the thickening is excavated somewhat, espe- 
cially near the proximal end of the costal, to form a broad groove 
for the ilium. The proximal end of the groove is closed partly 
by the ridge proceeding from the rib-head of the eighth costal and 
partly by a subcubic bone, which appears to be the tenth rib. 
This lies in a depression of the eighth costal. The iliac groove 
is 18 mm. wide at its upper end; and here its bounding walls are 
most prominent. Behind the ridge limiting the groove posteri- 
- - Qj.jy jj afiother groove, shallower and roughly excavated, which 
appears to have lodged a bone, probably the first sacral rib. 

The surface of the carapace is even, but it is sculptured everywhere by a network of 
shallow grooves. On the costals the network is the coarsest, the grooves lying from 2 mm. to 

5 mm. apart and mostly directed parallel 
with the length of the costal. On the 
neurals and peripherals the network is 
much closer. 

The sulci of the carapace are broad 
and shallow. There is no nuchal scute, 
the first marginals joining at the midline a 
distance of 44 mm. The length of the sul- 
cus between the first and the second margi- 
nals is 44 mm.; that between the second 
and the third, 23 mm. The sulcus between 
the eighth and ninth marginals, on the 
eighth peripheral, is 37 mm. long; the next 
one, 31 mm.; the next, 27 mm. 

The vertebral scutes of this species are 
much narrower than those of T. leslianus, 
as shown by the table above. 

The sulcus between the fifth vertebral 
and the hindermost marginals falls behind 
the suprapygal. 

The exact length of the plastron (fig. 
102) can not be determined, the connection 
between the epiplastron and the hyoplas- 
trals not being present. The length was, 
however, not far from 340 mm. The notch 
in the rear of the plastron was about 30 
mm. deep, so that the length along the 




KiG. 102. — Taphrosphys longmuchus. Plastron of 
type. Xj. Known portions represented by 
stippled areas. 



midline was about 310 mm. The epiplastrals are relatively small, especially when compared 
with those of Hydromedusa. The hinder end of each is broken off, but each was probably 
about 70 mm. long. The width was about 33 mm., while the greatest thickness of the outer 
end is 7 mm. The free border is acute at the midline, becoming subacute distally. Cope 
describes, under the name of mesosternal, a portion of the entoplastron, but this is now lost. 
He did not give the dimensions. He states that the extremities are acute-angled and that 
the bone was even more transverse than it is in T. molops. 



bothremyuida;. fi^i' 

At the midline the hyoplastra are 77 mm. long. The usual thickness of the bones is 6 mm. 
Laterally, each rises into a rather broad, but thin, axillary buttress. The bridge was probably 
about 125 mm. long. 

The hypoplastrals are 87 mm. long at the midlin . The bridge portions of the bones are 
mostly missing. There is no trace of the mesoplastrals, tho these doubtless were present. 

The xiphiplastrals extend 82 mm. along the midline. The notch in the rear is 90 mm. 
wide. The borders of the hinder lobe are thin and acute. On the upper surface of the xiphi- 
plastrals are the articular scars for the pubes and the ischia. The scars for the latter are 
mammiform, 17 mm. long and u mm. wide, and are sharply ridged and cleft. The pubic 
scars are somewhat elevated, 40 mm. long, 9 mm. wide, and rough. 

The arrangement of the scutes of the anterior lobe can not be wholly determined. On the 
epiplastra appear a pair possibly coalesct at the midline, the gulars. There was probably an 
intergular on the entoplastron. The sulci that separated the humerals from the pectorals is not 
seen. The latter scutes crost the plastron about 18 mm. in front of the hyohypoplastral suture. 
The abdominals are 40 mm. wide at the midline; the femorals, 90 mm.; the anals, 60 mm. 

Cope described limb bones which he regarded as two humeri and a small part of the prox- 
imal end of femur, but it is quite certain that what he called humeri are femora. The right 
femur lacks the fibular process and the distal end. Of the left femur there is the distal end. 
These bones agree closely with those of Hydromedusa, except that the tibial process extends 
down farther on the shaft. Cope estimates from these bones that the length was 97 mm. It 
was probably 10 mm. shorter. What seems to be the head of a humerus is too imperfect for 
definite conclusions. 




Fig. 103. — Taphrosphysleslianus. Anterior half of carapace of type. Xj. Known bones 

shown by stippled areas. 

Taphrosphys leslianus Cope. 

Text-figs. 105-106. 

Taphrosphysleslianus, CoPE, Ext. Batrach., Reptilia, AvesN. A., 1870, pp. 159, l66; Vert. Cret. Korm. 

West, 1875, p. 264.— Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 
Prochonias leslianus, CoPE, Ext. Batrach., etc., p. 165, line 14. 

The present species is, up to this time, known from only a single specimen. Cope's type. 
No. 1467, of the American Museum of Natural History. This specimen has not, until this 
time, been figured. In his description of the specimen Cope did not state the locality or the 
level from which it had been derived; but his label accompanying the specimen informs us that 
it was found at Hornersville, New Jersey. This is in Monmouth County. In his Cretaceous 
Vertebrata, page 264, he informs us that it belongs to "Greensand No. 5;" so called because 
he regarded the uppermost bed of Cretaceous greensand as representing the Fox Hills group. 

The type specimen consists of the left side of the nuchal, the first and second left periph- 
erals, a posterior peripheral, a part of both costals of the first pair, the whole of the thud 



112 



FOSSII, TURTLES OK NORTH AMERICA. 



costal of the left side, parts of the second and the fourth left costals, the distal end of the fifth 
right costal, the entoplastron, the left hypoplastron, and a portion of the right xiphiplastron. 

The species was one of relatively small size, with a deprest carapace (fig. 103), probably 
about 260 mm. long. The carapace is thin, the first costal being 6 mm. thick at the center; 
the fourth at its sutural border, 5 mm. thick. The first neural has a length of 35 mm. and a 
width of 18 mm.; the second, a length of 20 mm. and a width of 24 mm. The next two were 
somewhat longer. The broader end of each was in front, as in the genus generally. The 
nuchal bone was relatively long and narrow, the length being close to 67 mm., the width close to 
60 mm. The width in front was only 28 mm. This bone resembles closely that of Hydrome- 
dusa. Its anterior border was thin and acute. 

The first costal bone is 62 mm. wide fore and aft, and 75 mm. long and 6 mm. thick posteri- 
orly. On its inferior surface at the distal end is an excavation for the axillary buttress. This 
rises 30 mm. above the lower end of the bone and is 9 mm. wide. The third costal is 21 mm. 
wide and 105 mm. long. The right fifth is 33 mm. wide distally. On its inner surface, near 
the distal end, is an excavation for the inguinal buttress, 33 mm. long and 7 mm. wide. The 
first and the second, and probably all the other costals articulated with the peripheral bones. 
The rib-heads were moderately developt. 




Figs. 104 and 105. — Taphrosphys hsUanus. Portions of type. 

104. Entoplastron. X§. 105. Portions of reir of plastron. X^. 

Known bones shown by stippling. 

The first peripheral has a length of 42 mm. along the free border, and rises from this a 
distance of 49 mm. The second is 37 mm. along the free border and 33 mm. high. The free 
border of the first is acute; that of the second, subacute. The upper surface of each is convex 
in all directions. The thickness of the hinder end of the second peripheral is 8 mm. A posterior 
peripheral is 35 mm. long. It flares upward toward the free border. The latter is acute. 
The surface of the carapace is smooth, but there appears ever3rwhere a rather indistinct 
reticulation of grooves, which are narrower than the inclosed spaces. 

The sulci are shallow but not diflicult to trace. There is no nuchal scute. The first 
marginals join at the midline a distance of about 30 mm. The sulcus between the first and 

second marginals is 38 mm. long; that between the second and 
the third, 22 mm. Posteriorly the marginals rose rather high on 
the peripherals. The intermarginal sulci are nearer the anterior 
ends of the peripherals. The vertebral scutes have the dimensions 
given in the accompanying table. 

The entoplastron (fig. 104) is diamond-shaped, with rounded 
angles. The length is 30 mm.; the width, 31 mm.; the thick- 
ness, 3.5 mm. No other part of the anterior lobe is present. 
A considerable portion of the left hypoplastron is preserved (fig. 105). The hyoplastral 
border makes an angle of about 60° with the free border of the hinder lobe and a right angle 
with the median border, so far as the latter is represented. Cope appeared to think that the 



Vertebral. 


Length . 


i 

Width. 


2 
3 


48 


64 

•'5 



bothremydida:. 



uj 



/■ 



mesoplastron continued to the midline. This is not probable. The mesoplastron evidently 
extended inward only to the change in the direction of the anterior border of the hypoplastron; 
that is about one-third the distance from the peripherals to the midline. 

The inguinal buttress is prominent, but thin. The hinder lobe narrowed rapidly, so that, 
while about 150 mm. wide at the inguinal notch, it was only about 120 mm. at the hypo- 
xiphiplastral suture. The thickness of the bone behind the inguinal notch is 4 mm. Only a 
fragment of the right xiphiplastral is preserved. It extends from the midline to the free border 
along the anterior end; backward to behind the scar for the pubis. The free border was acute. 
The ischiadic scar is elevated, 28 mm. long, and 1 1 mm. wide. 

The surface of the plastral bones shows no sculpture. On the entoplastron may be traced 
sulci bounding laterally and posteriorly the intergular scute. Its anterior boundary can not be 
made out. On the xiphiplastron is seen the femoro-anal sulcus, 18 mm. behind the front border 
at the midline; 26 mm. toward the free border. 

No. 1471 of the American Museum of Natural History is referred provisionally to this 
species. The specimen was one of the Cope collection and accompanied another specimen 
that was labeled as coming from Barnesboro, Gloucester County, New Jersey. Without 
doubt it came from the Upper Cretaceous. It consists of the right epiplastron (fig. 106), a part 
of the left epiplastron, a portion of the left hyoplastron, a part of the left hypoplastron, and a 
few other fragments. The individual was nearly as large as the type of T. molops, and there- 
fore considerably larger than the type of T . hslianus. The plastral bones are thin, the thick- 
ness of the hinder end of the epiplastron being 8 mm., that of the hyoplastral border near the 
axilla, 9 mm. They are thinner than most of the corresponding bones of the type of T. loti- 
ginuchus, a considerably smaller individual. 

The epiplastron measures, in a straight line from the epiplastral symphysis to the hyo- 
epiplastral suture, 86 mm. The length of the symphysis is 20 mm.; the greatest width of the 

epiplastron is 37 mm. An abrupt ridge 
\ I I j^\ at the symphysis increases the thick- 

ness to 10 mm. The free border is 
subacute for a short distance on each 
side of the midline; elsewhere, obtuse. 
Most of the free border of the hyo- 
plastron is obtuse. 

The entoplastron had a width of 
close to 70 mm.; it was probably not 
over 60 mm. long. The thickness of 
the hyoplastron immediately behind the 
entoplastron is 6 mm. 

The fragment of hypoplastron ex- 
tends along the midline 90 mm. This 
suture was very jagged. At a ridge 
on the upper surface near the front of this bone the thickness amounts to 12 mm. Posteriorly 
it be:omes reduced to 5 mm. Of the hyohypoplastral suture there is present no mm. 
The hinder bone was somewhat overlapt by the hyoplastron. 

The inferior surface of these bones shows little sculpture. Only faint traces are seen of the 
network of grooves present in most of the species of the genus. On the hypoplastron are seen 
some faint grooves running at right angles with the median longitudinal suture. 

About certain of the anterior sulci there is some doubt. Those which appear to be present 
are represented in fig. 106. There is some doubt about the first sulcus represented on each 
side of the midline. Probably there ought to be a sulcus drawn across the anterior end of the 
entoplastron, but since this bone is missing we can not determine this. There is certainly a 
gulo-humeral sulcus across the epiplastron, and a humero-pectoral across the front ends of the 
hyoplastrals. The abdomino-femoral sulcus crost the hypoplastron 39 mm. behind the 
hyohypoplastral suture. Mainly on account of the thinness of these bones they are referred 
to T. leslianus; for there are no parts common to this specimen and the type. The parts of 
the hypoplastra present hardly coincide. No. 1471 was considerably larger. 





Fig. 106. — Taphrosphys leslianus. Anterior lobe of 
plastron. Xj. ' No. 1471 A. M. N. H. Known 
bones shown by stippling. 



8 



114 FOSSIL TURTLES OF NORTH AMERICA. 

Taphrosphys strenuus Cope. 
Figs. 107-11 I, 

Taphrosphys princeps. Cope, Cook's Gcol. New Jersey, 1868 (1869), p. 7^5 (name only). 

Taphrosphys strenuus. Cope, Ext. Batrach., Reptilia, Aves N. A., 1870, pp. 157, 166-B; Vert. Cret. 
Form. West, 1875, p. 264; Kerr's Report Geol. Surv. N. C, 1875, Append. B, p. ;?4; Amer. Nat- 
uralist, XII, 1878, p. 128. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 439. 

Prochonias strenuus. Cope, Amer. Naturalist, iii, 1869, pp. 89, 90; Ext. Batrach., etc., pp. 159, 167. 

Prochonias princeps, CoPE, Amer. Naturalist, in, 1869, p. 89; Ext. Batrach., etc., pp. 160, 167, line 44. 

Altho the present species had been previously mentioned, the earliest description of it is 
found in Cope's monograph on the Extinct Batrachia, Reptilia, and Aves of North America, 
page 166-B, issued in April, 1870. Here Cope states that he had in his possession 3 specimens. 
Only one of these, the second mentioned by him, has been found in his collection in the 
American Museum of Natural History. This has the number 1126. It appears that the first 
specimen mentioned by him had been intended as the type of the species, while the one now 
numbered 11 26 had been intended as the type of his species princeps. Before the description 
of the latter was printed it appears that he concluded to abandon it. Cope's description of 
T. strenuus bears evidences of imperfect revision. The second specimen, number 1 126, is 
labeled by Cope as having been obtained from the West Jersey Marl Company's pits at Barnes- 
boro, Gloucester County, New Jersey. The level is the Upper Cretaceous. The remains 
are much broken, consisting of about 75 pieces; and so many parts are missing that it is 
impossible to determine the exact position of many of those which remain. Of the neurals 
none is preserved. A few fragments of the costals remain. One, probably the fragment 




Fig. 107. — Taphrosphys strenuus. Anterior lobe of plastron. X^. No. 1 126 A. M. N. H. 
Known portions shown by stippled areas. 

whose width and thickness are given by Cope, is 91 mm. long, 57 mm. wide, and 10 mm. thick. 
The rib scarcely shows on the inferior surface. The upper surface presents a network ot 
shallow grooves at one end, but at the other the grooves inosculate but little and run nearly 
parallel with the sutural borders. Cope states that the peripherals are rough from the reticu- 
late sculpture. A fragment of what is believed to be an anterior peripheral shows a close 
network of grooves. The greatest thickness of this bone is 21 mm. Its free border is obtuse. 

Large portions of the plastron are preserved. The bones are thick and heavy. Pieces 
which belong at the crossings of the sutures measure in thickness about 18 mm., increasing in 
places to 20 mm. As in other species of the genus, the transverse sutural faces are oblique to 
the upper and lower surfaces of the plastron, so that the hyoplastron overlapt somewhat the 
hypoplastron; and the latter, the xiphiplastron. On the inferior surface the network ot 
grooves is coarse. On one fragment is seen a narrow and shallow sulcus. 

The anterior lobe of the plastron was broad and short (fig. 107). The right epiplastron is 
present and shows the whole of its free border, but some of the entoplastral border is broken 
away. To this is attacht a part of the free border of the hyoplastron. The width of the lobe 
at the hyoepiplastral suture was close to 300 mm. The front of the lobe was concave for a 
considerable distance on each side the midline. The fragment of hyoplastron is 18 mm. thick, 
but it thins to the subacute free border. On the epiplastron the free border becomes obtuse, 
the thickened part of the bone coming nearer the edge than on the hypoplastron. At the 
epiplastral symphysis the bone rather suddenly thickens to 22 mm. 



BOTHREMYDIDi*. 



"5 



The entoplastron must have been unusually large. Its anterior end approacht within 
32 mm. of the anterior border. The anterior angle was slightly greater than 100°. The sides 
bounding this angle were approximately 130 mm. long. The width must have been about 
160 mm. The inferior surface of the epiplastron displays an obscure reticulation, but the 
hypoplastron is smooth. 

There are present 2 fragments of the right xiphiplastron. One of these is the hinder angle 
and bears the ischiadic articulation; the other shows the bottom of the great notch at the rear 

109. and a part of the median suture. These 

fragments join and are represented by fig. 
108. The angular extremity had a very obtuse 
no. 'ree border. A short distance from the edge 

the thickness is 17 mm. The ischiadic articu- 
~~I latory (fig. 108, E) surface is elevated and 
about 40 mm. long and 24 mm. wide. It is 
now much eroded. In front of this articula- 
tion the thickness is 13 mm. The median 
longitudinal suture is coarse and jagged. Fig. 
109 represents a section across the hinderouter 
angle along the line CD of fig. 112. Fig. no 
is a section along the line AB of fig. 108. The 
posterior notch was about 180 mm. wide and 
relatively shallow. It appears to differ much 
from the notch in other species of the genus. 
While the free border of the extremity of 
the xiphiplastron is very obtuse, more anteri- 




p'lGS. 108-III. — Taphrosphys stretiuus. 

No. 1126 A. M.N. H. 



xi 



108. Right xiphiplastron, upper surface. <4B, line of section 

represented by figure no; C£), line of section 
represented by figure 109; £, ischiadic articulation. 

109. Section along line CD of figure 108. 
no. Section along line AB of figure 108. 
III. Section at hypoiiphiplastral suture. 



orly it becomes acute. Fig. in is a section at the hypoxiphiplastral suture. 

Cope described a bone which he regarded as the proximal end of the femur. With little 
or no doubt the bone is the left humerus. It presents close resemblances to the corre- 
sponding bone of Chelydra, the radial and ulnar processes, however, not being so thin as in 
the latter genus. Cope also described as a coracoid a bone which certainly belongs to the 
pelvis, having, as Cope states, 2 sutural faces and I cotyloid face. 

Taphrosphys molops Cope. 
Figs. 112-120. 

Taphrosphys molops, CoPE, Cook's Geol. New Jersey, 1868 (1869), p. 735 (name only); Anier. Naturalist, 
III, 1869, p. 89; Proc. Amer. Philos. Soc, xi, 1870, p. 274; Ext. Batrach., Reptilia, Aves N. A., 
1870, pp. 158, 159, plate vii, fig. 16, text-figs. 43, 44; Vert. Cret. Form. West, 1875, p. 263.— Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 

Taphrosphys molops var. enodis. Cope, Fxt. Batrach., etc., p. 162. 

Prochonias enodis. Cope, Ext. Batrach., etc., pp. 158, 160. 

Bothremys {Taphrosphys) molops, Zittei., Handbuch Palaeontologie, 1889, p. 547. 

Of this species Cope had a number of specimens, none wholly complete, most of them, 
very incomplete. The one which presented large portions of the carapace and the plastron 
had been obtained from the upper bed of Cretaceous greensand, at Barnesboro, Gloucester 
County, New Jersey. This specimen is now in the American Museum of Natural History and 
has the'number 1472. Portions were figured by Cope, and it seems proper to regard it as the 
type of the species. It is probable that the description of a specimen from Hornerstown 
appeared a short time before the detailed description given in the Extinct Batrachia, etc.; but 
that earlier description is not one that would enable us to determine the species, no part was 
figured, and the specimen was not intended by Cope to stand as the type. 

Of the carapace (fig. n2 ) Cope figured the nuchal and the right and left first peripherals. 
Portions of all these bones are now missing. The anterior outHne of the carapace was rounded 
as in r. longinuchus, and the free border was acute. The shell appears to have been of only 
moderate convexity. The width of the nuchal anteriorly was 50 mm.; its greatest width, close 
to 115 mm.; its length was probably about n5 mm. Its proportions were therefore as in T. 



ii6 



FOSSIL TURTLES OF NORTH AMERICA. 



longiriuchus. From the acute edge the bone thickens, at first rapidly,then gradually, to 12 mm., 
at the middle of the length. The first peripheral has an extent of 82 mm. along the free border, 
and 80 mm. from this to the hinder border. Its thickness is about that of the nuchal. The 
second peripheral measures 65 mm. along the free border. The edge is acute. 

None of the hinder peripherals is present, but there are parts of two from the bridge 
region. One of these is 65 mm. long and presents 2 faces, which meet at a right angle along an 




Fig. 112. — Taphrosphys tiwlops. Restoration of carapace of type. Xj. 
Known portions represented by stippled areas. 



No. 1472 A. M. N. H. 



obtuse lateral carina. Fig. 113 presents sections of the ends of this bone, a showing the ante- 
rior end, b, the posterior. A sulcus crosses both faces a little nearer the thicker end. The width 
of one face, probably that parallel with the plastron, is 43 mm. The other peripheral presents 
2 faces meeting at an acute angle. Fig. 1 14 shows sections of the ends of this bone, c being the 
anterior end, (/, the posterior. The length of the bone is 60 mm. It seems quite certain that 



BOTHREMYDIDiE. 



117 



the peripheral with the obtuse carina is the more anterior, the one with the acute carina 
belonging near the inguinal notch. 

Portions of the right and left first costals are present. These fragments show that these 
bones had an antero-posterior width ot about no mm. The thickness at the neural border is 
between 9 mm. and 10 mm. On the inferior side of the bone is seen the base of the rib-head; 
in front of this a sharp ridge corresponding to the first rib. Each of the first costals articulated 
with four peripherals. A ridge proceeding from the rib-head becomes, toward the peripheral 
border, high and broad. In this is excavated a large pit, 20 mm. wide and rising about 50 mm. 



b 






113. 114. 115. 

Figs. 113-115. — Taphrosphys molops. Xj. Xo. 1472 A. M. N. H. 

113. Sections of a bridge peripheral, a, anterior end; 6, posterior end. 

114. Sections of another peripheral of bridge, c, anterior end; d, posterior end. 

115. First costal, inner surface. Shows axillary pit. 

above the lower border of the costal (fig. 115 ). This is for the reception of the axillary buttress. 
Its upper end is much the deeper. 

There are fragments of the second, third, fourth, fifth, and sixth costals. These are 
represented in the restoration (fig. 112). From the proximal end of costals three and four we 
get an idea of the forms of neurals, but only approximate information regarding their widths. 
The third costal is 12 mm. thick at the neural border but only 6 mm. at the distal end. The 
fifth and the sixth costals are wider than those preceding them, as in T. longinuchus. 




Fig. 116. — Taphrosphys molops. Anterior half of p]a,stron of type. X}. 
Known portion.s stippled, m.p, mesoplastron. 

The upper surface of the nuchal and the anterior peripherals is rather strongly sculptured 
with a network of grooves. The interspaces vary greatly in form and size, few being less than 
5 mm. in diameter. Of the bridge peripherals one face is distinctly sculptured, the other 
obsoletely so. The sculpture on the costals is distinct, but usually not so strongly exprest as on 
the nuchal. The deepest furrows are mostly nearly parallel with the long axis of the costal. 

The sulci are shallow but distinct. There is no nuchal scute. The sulcus between the 
first marginals is 58 mm. long. Each measures 66 mm. along the free border. The second 
marginals had an equal extent along the free border. The width at the anterior end is 60 mm.; 
at the distal end, 40 mm. 



Il8 FOSSIL TURTLES OF NORTH AMERICA. 

The first vertebral scute had a length of about 90 mm., a width of about 140 mm. in front 
and of about 80 mm. behind. The approximate proportions of the next three are shown in the 
restoration. 

Cope figured (Ext. Batr.,Rept., etc., p. 160, fig. 43) a considerable part of the anterior lobe 
of the plastron. Another portion of the same specimen has been found, the border of the left 
axillary region, and this is included in fig. 1 16. This specimen suflices to give us a clear idea 
of the form of the anterior half of the plastron. This lobe had a length of about 135 mm. and 
a width of about 260 mm. It was rounded in front, with a slight median concavity. The free 
edges are obtuse, except at the union of the epiplastrals with the hyoplastrals. The thick- 
ness is everywhere close to 10 mm. The entoplastron was diamond-shaped, 65 mm. long and 
86 mm. wide. The suture of the hyoplastron with the hypoplastron was oblique to the surfaces 
of the bones, so that the hyoplastron overlaps the hypoplastron somewhat. A portion of the 
axillary region is preserved. The base of the buttress did not extend far within the free border 
of the anterior lobe. 

It is unfortunate that the epiplastron is not complete to the midline, for we are left in some 
doubt regarding the more anterior scutes. An intergular occupied a large part of the entoplas- 
tron. Cope represented this as overlapping some distance on the epiplastrals, but it seems to 
the writer that a sulcus crosses the entoplastron close to its anterior border. Probably the 
gulars met, possibly coalesct, at the midline, in front of the intergular. The humerals occu- 
pied the hinder half of each of the epiplastra. In some specimens of this genus there seems to 
be a scute cut oflF from the inner end of each gular. Such a scute, or such scutes, would be 
without name. Better specimens are required to settle this matter. The arrangement of the 
scutes in this region appears to resemble that of Chelodina. The pectorals measure 87 
mm. along the midline; the abdominals occupy the posterior 26 mm. of the hyoplastra. 

Cope presents a figure of the hinder half of the plastron of this specimen. It is difficult to 
determine just how much of that part of the plastron was in his hands. At present there is 
with the specimen only a fragment of the left inguinal region, a fragment of the left xiphiplas- 
tron, and the hinder angle of the right xiphiplastron. The latter is marked in Cope's figure 
with the letters Is. The fragment of the inguinal region extends forward to the suture with 
some bone, probably the mesoplastron. On the upper surface about 40 mm. behind this 
suture is a prominent ridge, the base of the inguinal buttress. This ridge is much more 
strongly developt than in T. longinuchus. 

The base of the xiphiplastron presents a coarse suture with the hypoplastron. The free 
border of the bone is acute. From the edge the bone thickens to 12 mm. On the upper 
surface of this bone is a part of the much elevated and rough articulating surface for the pubis. 
On the hinder angle of the xiphiplastron is the circular elevated and rough surface for articu- 
lation with the ischium. The notch in the rear of the plastron was about 140 mm. wide. 

On the anterior half of the plastron there is little evidence of sculpture. It is more conspic- 
uous on fragments of the hinder half, where it consists of a network of grooves. 

Cope mentions a specimen of this species from Hornerstown, New Jersey, which displayed 
the mesoplastral bones. These presented a rounded interior outline and were applied to an 
equal extent of the hyoplastrals and the hypoplastrals. They reacht one-third the distance 
toward the midline. The plastron was 10.5 inches between the inguinal notches. The speci- 
men is now lost. 

Another specimen. No. 1343 of the American Museum, an individual a little larger than 
the type, shows a portion of the right hyoplastron from front to rear. The length is 170 mm. 
Just behind the axillary buttress the posterior sutural border makes a turn forward at nearly 
a right angle. It appears evident that this was to receive the mesoplastron. No. 1474 of 
the American Museum, a part of the Cope collection of fossil reptiles, was obtained by Cope, 
February 22, 1871, and therefore not mentioned in his monograph of 1869 and 1870. It 
came from Birmingham, Burlington County, New Jersey. It furnishes, besides some fragments 
of costals, a large part of both hypoplastra and the complete left xiphiplastron (figs. 1 17, 1 18). 
The individual was of almost exactly the same size as the type. The distance along the median 
line, from the hyohypoplastral suture to the bottom of the notch in the rear, is 243 mm. The 
left hypoplastral came into contact with the right xiphiplastron, an irregularity not uncommon 
in the early turtles. The right hypoplastron is 115 mm. long; the left xiphiplastron, 105 mm.; 



BOTHRK.MYDIDiE. 



119 



both measured at the midhne. Neither hypoplastron exhibits either the inguinal region or the 
border for the mesoplastron. 

The hyoplastron overlapt somewhat the hypoplastron, and the latter similarly overlapt 
the xiphiplastron. At the antero-interior angle the hypoplastra are 16 mm. thick; at the 
postero-interior angle, 8 mm. The whole free border of the hinder lobe is acute. The hinder 
notch is 135 mm. wide, and 42 mm. deep. On the upper surface of the xiphiplastron (fig. 1 18) 




-Taphrosphys molops. 

117. Hinder half of plastron seen from below. X}. No. 1474 A. M. N. H. Known hones inclosed hy solid lines. 

118. Upper surface of left xiphiplastron. Xl- No. 1474 A. M. N. H. Shows ischiadic and puhic articulations. 

119. Three neural hones. Xj. No. 1470 A. M. N. H. 

are seen the circular scar for the ischium and the elongated one for the pubis. Both are elevated 
and furnisht with sharp ridges. 

The inferior surface of this part of the plastron is rough, due partly at least to erosion. 
The abdominal scutes occupy about the anterior 30 mm. of the hypoplastra. The femorals 
are large, measuring about 135 mm. along the midline; the anals, 75 mm. 

The specimen of this species mentioned by Cope as having come from Birmingham is now 
No. iiZQofthe American Museum. The femur supposed by Cope to belong with the specimen 
is missing. The remaining fragments throw no light on the species. 

No. 1470 of the American Museum is labeled by 
^^-v^ Cope as having been received by him "9/8, 1870," and 

was therefore not mentioned in his monograph. It was 
secured at Barnesboro. The individual was somewhat 
larger than the type. The nuchal bone has a length ot 
107 mm., a width anteriorly of 64 mm., and a maximum 
width of 117 mm. The notch in the midline behind, for 
the first neural, is only 24 mm. wide. Three neural 
bones (fig. 119) accompany the lot, but the exact position 
of none of them can be determined. None shows a cross- 
ing sulcus, and yet two of them were in contact. Figures 
\ of these are presented. 

\ The right first costal shows a great pit for the axillary 

,^--'' buttress. A fragment of the right fifth presents the some- 

r cr ./ .; ; ., i> - what eroded ridge and elongated pit for the inguinal 

Fig. 120. — Taphrosphys mnhps. Vox- """»•- ^ _, , *^ . ^ ■ .'^ ^, ,■ „.,..■, 

f .J ■ A ■ 1 lu o^oi buttress The atter is 10 mm. wide. I he pubic scai is 

tions of seventh and eighth costal uumcss. ± nv, lan^. .0 ., , ,1 1 tl 

bones and part of suprapygal. No. 53 mm. long and 1 5 mm. wide, elevated and rough. 1 he 

1477 A. M. N. H. pubic scar is circular. 




120 FOSSIL TURTLES OF NORTH AMERICA. 

Cope described a specimen from Barnesboro (Ext. Batr., Rept., etc., p. i6i) which is 
important because on it he based the distinction between his Taphrosphys and Prochonias. 
The specimen is No. 1477 of the American Museum. Cope states that this specimen exhibits 
an azygous bone in contact with the caudal marginal. As a matter of fact, all the species 
possess such a bone, the suprapygal, but Cope evidently meant a bone still in front of this. 
He states that this appeared to be the co-ossified proximal portions of the last pair of costals 
and that the fragment appeared to be bounded posteriorly by a continuous suture. A close 
examination of the region in question shows that it is identical in structure with the same 
region in T. sulcatus. A figure of the fragment is presented (fig. 120). The costals of the 
eighth pair meet in the midline, as usual. Behind them there is the anterior end of the 
suprapygal. Cope overlookt the sutures between the suprapygal and the eighth costals and 
the suture between the contiguous ends of the costals just mentioned. The xiphiplastron is 
present and shows the features described by Cope. The epiplastron lacks the outer end. On 
the free border, at a distance of 48 mm. from the symphysis, begins the gulo-humeral sulcus, as 
in the figure of the type. There appears to be no sulcus nearer the symphysis. Furthermore, no 
sulcus is seen running in front of the suture with the hyoplastron and toward the opposite side. 

Cope described a variety enodis of this species. The specimen on which this was based has 
not been seen by the present writer. According to Cope's description the free border of the 
hypoplastron was of equal thickness and equally obtuse, differing thus from the typical speci- 
mens of T. molops. Also the free margin of the hyoplastral was comprest and acute. It may 
be a distinct species. 

Taphrosphys dares sp. nov. 
Figs. 121-124. 

No. II 27 of the American Museum of Natural History belongs to portions of a fossil 
turtle which is a part of the Cope collection of fossil reptiles. No label came with the speci- 
men to tell what was its origin. The matrix adhering to the bones shows that the fossil did not 
come from the greensand of New Jersey. It consists of a yellowish or reddish sand in which 
are small flakes of mica. In his monograph of 1869 and 1870 Cope states, on page 167, that 
he had received some portions of a Taphrosphys from North Carolina, but the brief descrip- 
tion given by him does not agree sufficiently with the specimens here numbered 1127. Cope 
had also seen specimens of what he regarded as T. strenuus from Georgia, and it appears proba- 
ble that these are the ones. Further attention is given this matter below. It had evidently been 
Cope's intention to describe and figure these bones for he has indicated on them that they were 
to be numbered I, 2, 3, and 4. 

Wherever these bones were found, it is quite certain that they belong to a species hitherto 
undescribed, and were from the Upper Cretaceous. The lot presents the distal end of a fifth 
costal, probably the right, most of a right peripheral, the seventh or the eighth, the entoplastron, 
a large portion of the left xiphiplastron, and a fragment of the right xiphiplastron. 

The fragment of costal has a length of 180 mm. and a width of 85 mm. One border has 
a thickness of 11 mm.; the other, of 16 mm. The thicker sutural border presents a sort of 
tongue, the middle layer of the bone projecting beyond the outer and the inner. The thinner 
sutural border has the outer and the inner layers projecting beyond the middle, so that the edge 
is grooved. The sutures between the costals seem therefore to have formed what carpenters 
call a tongue-and-groove joint. At the distal end of the costal, on the thicker side, is a rough 
surface which indicates that the costal was slightly overlapt by one of the peripherals. 

The upper surface of this bone is smooth, but it is markt by a coarse network of shallow 
and thread-like grooves. 

On the inferior side of this costal, nearer the thicker side, is a pit for the reception of the 
inguinal buttress of the plastron. This pit is excavated in the summit of a ridge, the rib proper. 
The pit has a length of 60 mm. and a width of 23 mm. Its upper end is placed 105 mm. 
above the lower border of the costal. Below it is a rough surface which probably joined a 
portion of the buttress. Altogether it appears that this costal belonged to the right side; in 
which case the thicker border was the hinder one. 

The peripheral, the seventh or the eighth of the right side, is massive (fig. 121). Unfor- 
tunately the free border is everywhere broken away, so that we can not be certain whether it 



BOTHREMYDIDj*. 



121 



was acute or obtuse; but the probability is that it was acute. At one point it runs down to a 
thickness of only 11.5 mm. The fore-and-aft extent of the bone is 84 mm. The anterior 
border is very thick, 52 mm. at one section; and is excavated to form a part of the sternal 
chamber. The hinder border was not more than 15 mm. thick. The upper border joined the 
ends of 2 costal bones, proof that the peripheral does not belong to the axillary region of the 
left side. 

F~igure 122 is a section which is taken 20 mm. to the left of the front border. The costal 
that articulated with the anterior half overlapt the peripheral, but the succeeding one was 
overlapt by the peripheral. Satisfactory contact is not obtained between the peripheral here 
described and the fifth costal above described, so that their exact relations are not known. 

The upper surface of the peripheral (fig. 121) is ornamented by a network of grooves 
similar to those of the costal, but forming a much closer reticulation. That portion of the 
inferior surface of the peripheral covered by horn has a still closer network of grooves. On the 
upper surface is seen a triradiate sulcus, which bounds a portion of the third costal scute and 
portions of two marginals. 

Fig. 123 represents the entoplastron. Its length is 84 mm.; its width, 109 mm.; its 
greatest thickness, 14 mm. In the hinder border is a constriction. The outer surface presents 
neither sculpture nor distinct traces of sulci. 




Figs. 121-124. — Taphrosphys dares. Parts of the type. X^. No. 1127 A. M. N. H. 



121. Seventh or eighth peripheral, upper surface. 

122. Section of peripheral of fig. 121. 



123. Entoplastron 

124. Section along hypoxiphiplastral suture. 



The left xiphiplastron is present from the anterior border to the hinder end of the pubic 
scar. Its greatest width is 140 mm.; so that the hinder lobe was 280 mm. wide at the hypo- 
xiphiplastral suture. This suture was, as seen from below, a very close one; seen from above, 
the adjoining bones sent coarse digitations into each other. The anterior end of the right 
xiphiplastron overlapt the left as much as 28 mm. The median suture was jagged above, 
but more even on the under side. Near the antero-median angle the bone is 17 mm. thick; 
the postero-median portion, 12 mm. The free border, for some distance behind the hypo- 
xiphiplastral suture, is thin and acute. Fig. 124 is a section taken near the suture. The notch 
in the upper surface was filled by a digitation from the hypoplastron. On the upper surface 
of the bone is a large elevated area which articulated with the pubis. This articulation is 
much eroded. Its length was about 66 mm.; its width, about 27 mm. The lower surface of 
the bone shows no distinct sculpture. The femoro-anal sulcus crosses the bone, beginning at 
the median line about 45 mm. behind the hypoxiphiplastral suture and meeting the free border 
about 66 mm. behind the suture. 

What appears to be a portion of the right xiphiplastron is preserved. It bears the elevated 
articulation for the ischium. On the left is a part of the median suture. The articulation for 
the ischium is about 48 mm. long and 17 mm. wide. Unless there is some error regarding this 
bone, the notch in the hinder lobe must have been quite different from that of the other species 
of the genus. 



122 FOSSIL TURTLES OF NORTH AMERICA. 

While related to T. strenuus, this species shows several differences. So far as the sculpture 
of the costals can be compared, that of T. strenuus consisted of" more numerous and deeper 
grooves. The entoplastron of T. strenuus was much larger than that of the species here 
described. As shown by the section taken at the junction with the hypoplastron the xiphi- 
plastron of T. strenuus thickened much more rapidly and from a less acute edge, and its 
hinder portion was considerably thicker than in T. dares. 

In the collection of the Geological Survey of Georgia, at Atlanta, are some portions of a 
turtle which appears to belong to this species. Indeed, there are reasons for believing that they 
are portions of the same individual as the type bones. They are believed to have been secured 
in the same locality and formation as the carapace of Peritresius ornatus; that is, on Bonna- 
hachee Creek, Stewart County, Georgia, in the Ripley formation, of the Upper Cretaceous. 

Among the fragments is one including apparently the anterior inner angle of the hypo- 
plastron. Sixty mm. behind the supposed hyohypoplastral suture the thickness is 26 mm. 
Toward the suture mentioned the thickness is reduced. Here the upper two-thirds of the bone 
is beveled off, showing that the hyoplastron somewhat overlapt the hypoplastron. 

Another plastral fragment belongs probably to the hypoplastron behind the inguinal notch. 
Toward the median longitudinal suture the thickness is 16 mm. Toward the free border the 
thickness is much reduced, but the edge is rounded. The xiphiplastral bone in the American 
Museum shows that as the free border was continued backward it became acute. 

Another bone appears to be the second peripheral. It is 100 mm. long on the subacute 
free border. The height was originally at least 82 mm. and the greatest thickness is 25 mm. 
The upper surface is convex from end to end, nearly plane up and down. 

Named after Dares, a pugilist beaten in an encounter described in the MneiA, book v. 

Taphrosphys nodosus Cope. 

Taphrosphys nodosus, CoPE, Ext. Batrach., Reptilia, Aves N. A., 1870, pp. 159, 167, plate i, fig. 16; Vert. 
Cret. Form. West, 1875, p. 264. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 438. 

The type of the present species forms No. 1480 of the American Museum of Natural 
History. The remains are evidently those of a large, thin-shelled turtle; but these remains 
are meager and fragmentary. They were obtained at Hornerstown, Monmouth County, New 
Jersey, apparently from the uppermost bed of Cretaceous greensand. The fragments are 
charged with iron pyrites and are disposed to fall to pieces. Portions of costals are to be 
recognized and a peripheral or two. 

Cope figured portions of 2 costals. His fig. 16 is from a fragment 58 mm. wide and 10 mm. 
thick, but the inferior layer of the bone has peeled off. Another bone which comes down to an 
acute edge is probably a peripheral. Its thickness at a distance of 25 mm. from the edge is 
9 mm.; still farther away, it becomes 12 mm. Another piece of bone is part of a bridge 
peripheral, having two sculptured faces at about a right angle with each other. 

The sculpture will, more than anything else, assist in the recognition of the species. This 
consists of pits and grooves, the latter anastamosing more or less and separating tortuous 
ridges and pustules. The general effect is that seen on the carapace of a coarsely sculptured 
trionychid. About 4 ridges are crost by a line 20 mm. long. 

This species will perhaps eventually be found to belong to a genus distinct from Taph- 
rosphys. Indeed, the present writer knows of no characters distinguishing it from Peritresius 
ornatus (Leidy). 

Genus AMBLYPEZA nov. 

A genus of pleurodirid turtles which differs from Taphrosphys in having the nuchal bone 
shorter and its front relatively broader and in having the free borders of the hinder peripherals 
thick and obtuse. Apparently a nuchal scute was present. 

Type: J mhly peza entellus Hay. 

Amblypeza entellus sp. nov. 

Figs. 125-132. 

The type of this species is a lot of bones which belong to the collection of the Geological 
Survey of New Jersey, and which were loaned to the writer by the present State geologist, Dr, 



BOTHREMYDID^. 



123 



Henry B. Kiimmel. These bones had lain for many years in the basement of the capitol and 
all knowledge of their origin had been lost. Without doubt, they had been obtained from the 
Upper Cretaceous greensand of New Jersey. 

Of this individual there are large portions preserved, but there are so many parts missing 
that the shell can be only partially restored. Of the carapace there were secured a considerable 
part of the anterior and posterior free borders and some fragments of costals. Of the plastron 
some important parts can be identified. The individual is estimated to have had a carapace 
about 700 mm. long. 

Most of the nuchal bone is present (fig. 125), but, on account of the absence of a section of 
it, its exact width can not be determined. It was not far from 120 mm. The hinder portion is 
missing. The thickness near the midline in front is 13 mm.; backward the bone thins to 
6 mm., while at its outer ends it is 18 mm. thick. The whole free edge is obtuse. The first 
peripheral (fig. 125) has a length along the free border of 83 mm., a fore-and-aft extent of 
65 mm. The thickness at the suture with the second peripheral is 24 mm.; at the suture 
with the first costal, 8 mm. The second peripheral (fig. 125) extends 90 mm. along the free 
border; 70mm. fore and aft; and is 26 mm. thick where it joined the third. Its hinder 
border somewhat overlapt the first costal. 






Figs. 125-130. — Amhlypeza entellus. Portions of the type in State collection of New Jersey. 

125. Nuchal and anterior peripherals of type. X}. 127. .Section along intermarginal sulcus of peripheral 

nu.pj nuchal plate; nu. 5, nuchal scute; pfr. i, of fig. 126. Xj. 

first peripheral. 128. Hinder peripheral. Xj. 

126. Hinderperipherals(7?and8!')ofleft sideof type. X}. 129. Section of peripheral of fig. 128. Xj. 

130. Inner surface of fifth costal. Xj. Shows surface for inguinal buttress. 

The peripherals behind the bridges were larger and thicker than those in front. One 
whole one and portions of two others are present. The free borders of these are thickened and 
very obtuse, thus contrasting strongly with the corresponding bones of Taphrosphys. The 
exact positions of these posterior peripherals can not be made out. Fig. 126 represents portions 
of two; and from the thickness of the bone at the left hand, 27 mm., and the height of the 
costo-marginal sulcus, that peripheral is believed to belong not far from the inguinal notch, 
being possibly the left eighth. Fig. 127 is a section taken along the intermarginal sulcus. The 
upper surface is convex in all directions. On the under side the horn-covered surface rose 
above the free border about 45 mm., descending somewhat backward. Fig. 128 represents a 
complete peripheral, probably the tenth of the right side; fig. 129 is a section of the anterior 
end. It measures 104 mm. along the free border and is 104 mm. high. The thickness near the 
lower border is 21 mm.; at the upper border, 13 mm. On the visceral side the surface covered 
with horn is 40 mm. wide anteriorly, but toward the hinder end is only 15 mm. wide. The free 
border is very obtuse. 

A fragment of a costal has a length of 130 mm., a width of JJ mm., and a thickness of 
15 mm. at the sutural border, 20 mm. through the rib. Another fragment is part of the fifth 



124 



FOSSIL TURTLES OK NORTH AMERICA. 



costal (fig. 130) and shows the scar for the articulation of the inguinal buttress. This fragment 
is 91 mm. wide, 13 mm. thick at the sutural border, and 29 mm. thick through the ridge in 
which is excavated the pit for the inguinal buttress. This pit is shallow and quite different 
from that of any species of Taphrosphys. 

The sculpture of the anterior peripherals is obscure, due probably to weathering; that 
of the hinder peripherals is more distinct. It is very different from that of Taphrosphys dares, 
and consists of a pretty close network of rather broad grooves. On the costals the interven- 
ing spaces are about as broad as the grooves and the latter run mostly parallel with the long 
axis of the bone. 




Figs. 131 and 132. — Amhlypeza entellus. Known parts shown by stippling. 
131. Restoration of anterior lobe of plastron. Xj. iji. Restoration of hinder half of plastron of type. X^. 

Appearances indicate that there was a nuchal scute about 60 mm. wide. If this be true, 
the generic distinctions are strengthened. The sulci are, however, obscure. The first vertebral 
scute extends much nearer the front of the nuchal bone than in any species of Taphrosphys. 
At the midline the distance is only 20 mm. If there is a nuchal scute, the first marginal 
measures only 64 mm. along the free border of the carapace. The width at the proximal end 
is 24 mm.; at the distal end it has increast to 40 mm. The second marginal is 86 mm. long 
and 60 mm. high at the middle of the length. The marginal lying on the supposed eighth and 
ninth peripherals is 102 mm. long and 85 mm. high in front. On the supposed tenth 
peripheral the marginal descended to within 42 mm. of the lower border of the bone. 



BOTHREMYDID^. 



'25 



The bones of the plastron (figs. 131, 132) are so fragmentary and contacts between the 
pieces so rare that it is difficult to obtain measurements. The right epiplastron (fig. 131) is 
represented by two fragments. One of these furnishes the symphysis. This is 36 mm. long 
and the bone is 22 mm. thick. The hinder border was in contact with the entoplastron and is 
18 mm. thick. The other fragment furnishes the hinder end of the epiplastron. There is 
missing probably only a few millimeters of bone between the two pieces. The epiplastron, and 
therefore the whole anterior lobe, was of a different form from what we see in Taphrosphys 
strenuus. From the obtuse free border of the epiplastron to the entoplastron was nearly 
70 mm. If the restoration here attempted approaches correctness the entoplastron must have 
been at least 200 mm. wide. 

The hypoplastra at their inner anterior angles are 23 mm. thick. The upper layers of 
the hyoplastra overlapt somewhat the hypoplastra. 

Of the hinder lobe (fig. 132) there are preserved several pieces. The restoration of this 
lobe has been attempted and the recognized pieces of the lobe are represented by the stippled 
areas. On the right side is seen a fragment which extends from near the inguinal notch to the 
hypoxiphiplastral sulcus. The free border is rather obtuse, but becomes less so toward the 
suture. The upper surface rises rapidly about 40 mm. and the thickness becomes 20 mm. On 
the left side is a fragment presenting a portion of the hypoplastron and no mm. of the free 
border of the xiphiplastron. The border may be called subacute. Three pieces of the right 
xiphiplastron enable us to make out its characters; two of these form close contact and give us 
the hinder angle and the notch. The other piece bears on its upper surface the eroded elevated 
scar for articulation with the pubis. It appears to have the size and form seen in the species of 
Taphrosphys. Just outside of this surface the bone is 17 mm. thick. 

The notch in the rear of the plastron had a width of about 185 mm. and a depth of about 
80 mm. As the backwardly projecting angle of the xiphiplastron is approacht the bone 
thickens and the free border becomes very obtuse. The thickness just outside the ischiadic 
scar is 18 mm. The latter was elevated and rough, and apparently pear-shaped in outline. 

The anterior end of the epiplastron is ornamented with a close network of grooves, which 
inclose spaces extremely irregular in size and form. On the hinder end of the bone the inclosed 
areas are larger, more elongated, and parallel with the free border of the bone. The sculpture 
of the rear of the plastron is similar to that just described. It is obscure on the central portions 
of the plastron. The sulci of the plastron are obscure. On the epiplastron there is a gulo- 
humeral sulcus beginning 38 mm. from the epiplastral symphysis and running backward 
and a little outward to the suture with the entoplastron. 

This species is dedicated to Entellus, who, though old and lacking confidence, had endur- 
ance and beat his younger opponent (Virgil's ^neid, book v). 

Genus NAIADOCHELYS nov. 

An imperfectly known genus of Pleurodira, having the plastral surface smooth, the hinder 
lobe deeply and broadly notcht, and a large elevated ischial articular surface which extends to 
the midline. 

Type : Naiadochelys ingravata Hay. 

This genus differs from Taphrosphys in having the lower surface of the plastron smooth, 
instead of ornamented with longitudinal or anastomosing grooves, and in having a much more 
extensive articular surface for the ischium. At present, only the hinder half of the xiphiplastron 
is known. 

Naiadochelys ingravata sp. nov. 

Fig- 133- 

This species is based on a fragment furnishing about the hinder half of a left xiphiplastron. 
It was collected in the year 1900, by Professor F. W. Putnam, having been brought to him by 
Indians, at Chaco Canyon, New Mexico. The geological formation whence it was derived is 
uncertain, but it was probably the Laramie, which is well developt in that region. The 
specimen has been transferred from the department of anthropology of the American Museum 
of Natural History to the department of vertebrate paleontology. The present number of the 
specimen is 6078. The small amount of matrix yet clinging to specimen is a yellow sandstone. 




126 FOSSIL TURTLES OF NORTH AMERICA. 

The fragment of xiphiplastron present indicates a turtle of moderate size, but furnisht 
with a very thick and heavy plastron. It is estimated that the plastron had a total length of 
i8 inches (about 460 mm.). The thickness, to the summit of the ischial articular surface, 

is 26 mm.; at the base of this, where it appears to be rising 
toward the pubic articular surface, 19 mm.; at the sutural 
border for union with the bone of the opposite side, 11 mm. 
In a specimen oiTnphros phys molops. No. 1474, these measure- 
ments, in the order given, are 15 mm., 10 mm., and 10 mm. 
This specimen is estimated to have had a plastron 21 inches 
long. 

The lower surface of the bone is very flat and smooth. 

From the outer border the upper surface rises at first rapidly, 

then more slowly, to the base of the articular eminence, being 

thus convex. From the hinder border the upper surface rises 

more and more steeply, being thus concave. The articular 

surface for the ischium is much larger than in Taphrosphys. 

"~"^ It is approximately triangular in outline, the hinder border 

Vni- 133- Naiadochelys itigia- running somewhat parallel with the hinder border of the bone, 

vata. Portion of left xiphi- ^j^n^ j|^g ^^j^j. border runs parallel with the outer border 

plastron forminc the type. r u u j i »». r » .. i- -^ 'i-l- >• 1 

' , ^^ , o A .« -.- .. 01 the bone and about 2'; mm. distant irom it. Inis articular 
XA. No. 6078 A. M. N. H. ^ , ■ u I. jr Jir • l r 

surface extends mesially to the midline, difienng thus from 

Taphrosphys and resembling Hydromedusa. The figure presented will show the form and 

extent of the surface. At its summit it has been somewhat eroded, and the border at the 

anterior angle may have been slightly extended. Where not eroded, the summit is roughened 

to afford attachment to the ischium. At the anterior angle of the eminence the smooth surface 

of the plastron at first descends, then begins to ascend, as if rising toward the articular eminence 

for the pubis; but no part of this is present. 

SuperfamUy CRYPTODIRA Cope. 

Thecophorous turtles having the carapace composed of neurals, costals, and peripherals. 
The neurals in a few cases greatly red\iced. The plastron having the epiplastra in contact with 
the hyoplastra. Entoplastron occasionally wanting. Mesoplastrals, so far as known, never 
present. Temporal roof varying from complete to obsolete. Pterygoids extending backward 
between the basisphenoid and the quadrates. Neck bending in a sigmoid curve in a vertical 
plane and capable of being retracted between the scapulae. Elements of the pelvis never 
suturally joined to the carapace and the plastron. 

Of the Cryptodira there are 8 families and about 140 living species. Their geographical 
distribution is discust on page 31 and illustrated by fig. 10. To a greater extent than the mem- 
bers of any other superfamily the Cryptodira have been able to adapt themselves to the varying 
conditions of the globe. All lands, except the very coldest and the dryest, have been occupied 
by them. Most deserts have their species. Species inhabit forests and prairies, swamps, 
rivers, lakes, and the high seas. Their structure varies accordingly. By their wide geograph- 
ical distribution, the number of their species, and their great differentiation of structure, 
the Cryptodira proclaim themselves to be the successful group among the turtles. 

Geologically they reach back, according to present knowledge, to the Jurassic, being 
represented in the Lower Kimeridgian of Europe by species of Thalassemydidae. 

Fig. 8 represents the author's present views regarding the origin and relationships of the 
various families. Much remains to be determined as to these relationships. 

Family THALASSEMYDIDiE Rijtimeyer. 

Shell more or less incompletely ossified. Usually at least a central plastral fontanel 
present; often also costo-peripheral vacuities. Plastron loosely connected with the carapace; 
never closely sutured thereto. Limbs fitted for walking; never developt as flippers. Skull, 
when known, with the temporal fossae more or less rooft over. Triturating surfaces of the 
jaws probably always broad. Neck short. 



THALASSEMYDID^. 127 

The present writer unites what have usually been regarded as two distinct groups of turtles. 
For the one there have been employed the names Thalassemydes, Thalassemydidje, Eury- 
sternidse, Aciehelyidae, for the other the family names Propleuridae, Lytolomidae, Chelonemy- 
didae. The first includes mostly Jurassic genera, the second, Cretaceous and Lower Tertiary 
forms. Recently a number of writers have grouped the latter in the family Cheloniidae. 

The relationships of the Jurassic genera to Osteopygis and its kindred appear to be too 
close to permit the recognition of two distinct families. Much remains to be learned about the 
skulls of both groups; but so far as they are known, there appear to be no violent disagree- 
ments. In all, the temporal region is more or less completely rooft over by bone, and the jaws 
are, usually at least, fitted for crushing hard food. Nevertheless, among the Cheloniidae, and 
some other families, there is the greatest variation in respect to the character of the jaws. 

A remarkable resemblance is to be observed between the shells of Aplax {Eurysternum) 
and Osteopygis. Zittel's figure of the former (Paiaeontographica, xxiv, pi. xxvii) shows that 
the hyoplastron sent foi-ward a long process that came into contact with the second peripheral, 
just as in Osteopygis. The hypoplastron, too, reacht backward to the eighth peripheral. 
There were, likewise, extensive fontanels enclosed by the outer ends of these plastral bones 
and the peripherals. 

As indicating on the part of writers a recognition of close relationship between the various 
elements united here into one family, it may be recalled that, while the later forms have been 
actually incorporated with the Cheloniidae, the Jurassic Thalassemydidse have been regarded 
as the source from which our living sea-turtles have been originally derived. 

Kev to the Genera of Thalassemydidj!;. 

A. A pit in the second peripheral for the hyoplastron. 

a. At least the two anterior peripherals suturally joined with disk of carapace. Rib of 

eighth costal entering a pit in the tenth peripheral. Shell smooth or pitted Osteopygis 

AA. No pit, so far as known, in the second peripheral for hyoplastron. 

h. Two anterior peripherals of each side articulating with the disk of the carapace. 
c. Rib of eighth costal entering pit in eleventh peripheral ; the skull and lower 

jaw unknown Catapleura 

bh. None of the peripherals, so far as known, articulating with the disk. 
</. Lower jaw not furnisht with a beak. 

e. Symphysis of lower jaw not more tlian two-thirds the width of the 

jaws at the mental foramina Lytoloma 

ee. Symphysis three-fourths the width given Erquehnnesui 

dd. Lower jaw with beak. Skull with rooft temporal region. Choan;c in 

anterior half of roof of mouth. Shell not known Rhetechelys 

Genus OSTEOPYGIS Cope. 

Carapace including 8 pairs of costal plates and 1 1 pairs of peripherals, with all or only a 
part of the peripherals suturally articulated with the costals and the suprapygals. All the 
costals sending the ends of their ribs into pits of the corresponding peripherals. Five vertebral 
and 4 pairs of costal scutes. The nuchal scute much wider than long. Plastron relatively 
small; its connection with the peripherals extensive, reaching from the second to the eighth 
peripherals, not by close sutures. Bridge relatively narrow. Fontanels in the midline and at 
the ends of the hyohypoplastral suture. Inframarginal scutes present. Lower jaw with a 
broad and flat crushing surface; not beakt. 
Type: Osteopygis emarginatus Cope. 

This genus was establisht by Cope in i868 (Proc. Acad. Nat. Sci. Phila., p. i47)> and 
had for its type O. emarginatus. With it were included these species described at a later date: 
0. sopitus, 0. clulydrinus, and 0. repandus. In his next publication on the subject (Amer. 
Naturalist, in, 1869, p. 88) Cope subdivided the genus, setting up Propleura with O. sopitus 
( = 0. horealts) as the type. The two genera were regarded as differing in this, that Osteopygis 
had all the peripherals suturally united with the disk of the carapace, while in Propleura only 
the most anterior peripherals were so joined. 



128 FOSSIL TURTLES OF NORTH AMERICA. 

When this author's work (Synopsis of the Extinct Batrachia, Reptilia, and Aves of North 
America) was issued in 1870, he described (pp. 105-234) both Osteopygis and Propleura 
as possessing 10 pairs of costal plates. In the latter genus he included only the species 
sopitiu, his repandus being made the type of a new genus Catapleura, and his chelydrinus 
being referred to Osteopygis. Cope concluded that there were 10 pairs of costals because he 
found a pit, as if for a rib, in the second peripherals and supposed that he had found a pit in 
each of the eleventh peripherals. 

In that portion of the Synopsis (pp. 235-252) which appeared in December, 1870, Cope 
stated that as regards Osteopygis the ascription to it of 10 pair of costals was an error, the last 
peripheral not having had a costal corresponding to it. As to Propleura, he adhered to his 
previous opinion that it possest 10 pairs of costals. 

In 1875 Cope (Vert. Cret. Form. West, p. 257) had concluded that the possession by Pro- 
pleura sopita of 10 pairs of costals was very doubtful; and this species, with platylomus and 
his new erosus were referred to Osteopygis; while chelydrinus went to Catapleura. Cope 
still believed that Osteopygis possest at least 9 pairs of costals. 

In 1882 (Proc. Amer. Philos. Soc, xx, p. 144) and again in 1884 (Vert. Tert. Form. 
West, p. 112), Cope defined Osteopygis as having 10 pairs of costals and Propleura as having 
9, statements directly opposite to those formerly made. 

The correction of Cope's errors regarding the number of costals in the species of this group 
was made by Dr. Baur (Zool. Anzeiger, xiv, 1889, p. 42). He studied the very complete 
specimen which has since served Dr. Wieland as the type of 0. gibhi; and from this he 
concluded that there were only 8 pairs of costals, and that the pit in the second peripheral 
was for the reception of a process of the hyoplastron. Baur examined also Cope's types of 
the species of Osteopygis, Propleura, and Catapleura and concluded that there were no generic 
differences among them. 

Baur's results respecting the number of costals have been confirmed by Wieland. Never- 
theless, Wieland adopts Cope's genus Propleura. He holds that Propleura differs in having 
costo-peripheral fontanels, conical rib-pits, and humeri grooved on their distal ends. 

So far as concerns the grooving of the distal articular ends of the humeri, the present 
writer does not believe that enough is known about the humeri, not only of the species of the 
group in question but of the 'living species, to justify the use of the character proposed by 
Wieland to separate genera. Among species of Testudo it is found that the distal end of the 
humerus of many, perhaps of most, is smooth and rounded; but that of Testudo orthopygia 
has a broad trochlear groove. 

Analysis of the Species of Osteopygis. 

1. All the peripherals sutured to the costals {Osteopygis). 

A. Posterior peripherals emarginate; upper borders of peripherals not notcht by the 

rib pits; thickness of outer end of nuchal about one-eighth its width emarginatus 

AA . Posterior peripherals not emarginate. 

a. Outer end of nuchal about one-eighth the width in front ; upper borders of 

peripherals notcht by rib-pits gibbi 

aa. Thickness of outer end of nuchal about one-sixth its width in front; upper 

borders of peripherals not notcht by rib-pits robustus 

2. Peripherals 3 to 10 inclusive free from the peripherals (Propleura). 

A. Hinder peripherals angulated at end of sulcus chelydrinus 

A A. Hinder peripherals neither angulated nor emarginate. 

a. Rib-pits of eighth and succeeding peripherals flattened; one face or both notcht 
by rib-pits. The seventh at least two-thirds as wide as long. 
b. Bones thick and heavy; thickness of distal end of first peripheral in its length 

3.5 times; only upper face of hinder peripherals notcht by rib-pits. .. erosus 

bb. Bones thinner, thickness of distal end of first peripheral in its length 
4.4 times; both faces of upper border of hinder peripherals notcht by 

rib-pits borealis 

bbh. Bones thinner; thickness of first peripheral in its length 4.4times; rib-pits 

of sixth and seventh peripherals flattened; both faces of peripherals notcht platylomus 
aa. Seventh peripheral only half as wide as long sopitus 



THALASSEMYDID^. 



129 



The possession of conical rib-pits on the part of Wieland's Propleura borealts, if a good 
generic character, removes it from Propleura, for the type of the latter, P. sopita, has the pits 
in the hinder peripherals all flat. This statement is true as regards Leidy's type of his Chelone 
sopita and of Cope's specimen, now regarded as belonging to Osteopygis boreaUs. 

There remains therefore only the presence of the costo-peripheral fontanels to separate 
Propleura from Osteopygis. This is one of those characters which can not be sharply defined 
and which may be expected to exhibit in closely related species all gradations. We can not 
be sure that at any time a species may not be found in which a number of the lateral peripherals 
are joined suturally with the costals, while others are free. Indeed, we can not be certain that 
in some of the described species of Propleura some of the lateral peripherals did not become 
sutured to the contiguous costals. An aged Colpochelys kempt has a perfectly solid carapace. 

Therefore, until better characters have been proposed for the separation of Osteopygis 
and Propleura, the present writer prefers to employ only the former name. 

Osteoygis emarginatus Cope. 
Telt-figs. 134-141. 

Osteopygis emarginatus, Cope, Proc. Acad. Nat. Sci., 1868, p. 147 (nom. nud.); Cook's Geol. New Jersey, 
l868 (1869), p. 735 (nom. nud.); Amer. Naturalist, in, 1869, p. 89; Ext. Batrach., Reptilia, Aves 
N. A., 1869, pp. 135, 136, 235, plate vii, fig. 3; Vert. Cret. Form. West, 1875, p. 259. — Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 

Osteopygis platylomus, Cope, Ext. Batrach., etc., p. 134, fig. 39 in part. 

The two specimens described by Cope under this name are in the American Museum of 
Natural History. Both had been discovered in the upper bed of greensand of the Upper 
Cretaceous, at Barnesboro, Gloucester County, New Jersey. The bones figured by Cope 




Fig. 134. — Osteopygis emarginatus. Nuchal, right first peripheral, and portions of first 
costals. Xi No. 1485 A. M. N. H. 

c.p. I, First costal bone; nu.p, nuchal bone; nu.s, nuchal scute; per.i, first peripheral. 

belong to the second individual described by him. This is in the American Museum and bears 
the number 1485. , 

There is, however, some doubt attached to the peripheral which furnisht Professor Cope s 
figure y. In his explanation of the figure. Cope says that it is the tenth of the left side. 
In reality, it is the eighth. He states that the eleventh peripheral of the right side is present, but 
it is not in the collection. It seems probable that the one he called the eleventh is the same one 
he called the tenth of the left side. On the bone there has at some time been written, probably 



130 



FOSSIL TURTLES OF NORTH AMERICA. 



by Cope, " lO R," but the digit on the right had evidently been changed from " i " to "o" and 
an "L" to an "R." Finally ink lines had been drawn across these characters and "8" 
written near by. These changes indicate that originally Cope regarded the peripheral as the 
eleventh; that before he went into print he came to regard the bone as the tenth; and 
that at some later period he became convinct that it was the eighth. The measurements 
of the bone do not at all agree with those of the tenth peripheral of Cope's first specimen, 
but they do agree quite closely with those of the tenth of the second. 

Cope (his plate vii, fig. 3«) has represented the nuchal, the right first peripheral, and the 
proximal end of both first costals. These elements are here shown in fig. 134. The free 
border of the nuchal and first peripherals is obtuse. At the midline, back from the free 
border, the thickness is 15 mm. The free border of the nuchal is 122 mm. long, in a straight 
line. The first peripheral is 65 mm. along the free border, and 48 mm. at right angles with 
this. It is 17 mm. thick at the proximal end (fig. 135) and 19 mm. at the distal (fig. 136). 
The upper surface is convex, with a low concavity running parallel with and just behind the 
free border. 

The fifth left peripheral (Cope, pi. vii, fig. 3^, seen from the lower and inner faces) 
measures 77 mm. along the free border; 58 mm. on the upper face anteriorly, 60 mm. poste- 
riorly; 52 mm. across the inner face anteriorly, 48 mm. posteriorly. The inner face contains 
a large pit, circular in section, for the end of the rib of the third costal. This pit occupies 
about one-third the length of the peripheral. The upper face is concave up and down; the 
lower face is convex. There was no sutural connection with the plastron, but the upper 
border of the upper face was suturally joined to the costal. Fig. 137 represents the anterior 
end of this bone; 138 the posterior end. The hinder end of the bone corresponds exactly with 
the anterior end of the sixth peripheral of 0. erosus. 




139- 



KlGS. 135-141. — Osteopygis emarginatus. Portions of shell. Xj. No. 1485 A. M. N. H. 

135. Section of proximal end of first left peripheral. 139. Anterior end of eighth left peripheral. 

136. Section of distal end of first left peripheral. 140. Hinder end of eighth left peripheral. 

137. Anterior end of fifth left peripheral. 141. Neurals. 

138. Posterior end of fifth left peripheral. 

The eighth peripheral (Cope, plate vii, fig. y) is nearly plane above. The free border is 
mostly missing, but it had apparently about the form shown restored in Cope's figure. It 
was therefore rather strongly emarginated, the bottom of the emargination being at the end of 
the sulcus. The fore-and-aft extent of the bone at the middle of the height is 90 mm.; the 
height from the end of the sulcus, lOO mm. It must have been about 115 mm. high at the ends 
of the bone. The greatest thickness at the anterior border (fig. 139) is 24 mm.; on the 
posterior border (fig. 140), 22 mm. On the upper border the bone was sutured to the costal 
touching it. The rib-pit, mostly in the posterior half of the inner face, is 30 mm. long and is 
flat. It does not notch the upper face. 

The first costals (fig. 134) present only their proximal halves. The greatest width fore 
and aft is 97 mm. The thickness in front is 12 mm.; posteriorly, 8 mm. The rib-head was 
prominent. In front of the ridge descending from it is a rough surface to which was articulated 
the rudimentary first rib. 

Among other fragments of costals is the distal two-thirds of one, probably the fourth. It 
is possibly the one mentioned by Cope as having a width of 3 inches and 2 lines, this being the 



thalassemydidj^. 131 

width not far from the distal end. Its thickness is about 9 mm. It is interesting, because it 
shows plainly that it was articulated suturally with the contiguous peripheral. The bone is 
traverst longitudinally by a deep sulcus. Its surface is pitted just like a costal of O. erosus. 

The neural figured by Cope (fig. 141) is present, as well as fragments of two others. The 
one figured is 55 mm. long and 36 mm. wide, deeply notcht in front, and crost behind by a 
transverse sulcus. It is probably one of the more posterior neurals, the seventh or the eight. 

The surface of the anterior bones of the carapace is relatively smooth. The fifth peripheral 
is somewhat pitted, but the result probably of accident. 

The nuchal scute measures 60 mm. in front, no mm. behind, and 25 mm. fore and aft. 
The first marginal measures 52 mm. along the free border and 39 mm. across the end next the 
second marginal. 

The first vertebral had a width anteriorly of 185 mm. and a length of 82 mm. The second 
vertebral appears to have been about 75 mm. wide. No trace is seen of the costo-marginal 
sulcus on the upper border of the fifth peripheral; but doubtless on the sides of the shell the 
sulci followed closely the costo-peripheral sutures. On the eighth peripheral the costo-mar- 
ginal sulci lie from 12 mm. to 25 mm. below the upper border of the bone. 

The femur is represented by a portion of the proximal end; but the head and both trochan- 
ters are missing. The shaft has a diameter of 15 mm. 

The first specimen described by Cope bears the American Museum's number 1344. It 
was an individual of almost exactly the same size as that regarded as the type. It furnishes 
the nuchal, the first right peripheral, the first, second, fourth, fifth left peripherals, the proximal 
half of the first left costal, some other unimportant costal fragments, a part of the right hyo- 
plastron, a part of the right hypoplastron, and the greater part of both xiphiplastra. Cope 
mentions additional peripherals, but they do not accompany the bones mentioned above, and 
have not been recognized in the Cope collection. 

That paragraph of Cope's description which occupies the upper two-fifths of page 137 of 
the Synopsis may be regarded as a riddle; for in it Cope constantly compares the species he is 
describing with itself. The explanation appears to be the following: With the specimen, in 
Cope's writing, is a label "Osteopygis platylomus. Cope, type: nr. Barnesboro, Gloucester 
Co., N. J. " At some subsequent time two pencil lines have been drawn through "platylomus." 
There can be no doubt that the specimen is the one Cope describes as O. emarginatus; and 
there can be little doubt that the plastral bones furnisht the right hand portion of Cope's 
fig. 39, said to be that of the plastron of 0. platylomus. We may suppose therefore that at one 
time Cope regarded this specimen as 0. platylomus and intended to make it the type of the 
species; but coming to see that it was 0. emarginatus, a portion of the manuscript was 
transferred to the latter species without proper changes. 

The parts common to this specimen and the type of the species present no important 
differences. The second peripheral is 75 mm. long; 57 mm. at right angles with the free border 
and at the proximal end, and 21 mm. thick at the same end. The distal end has a large exca- 
vation for the process of the hyoplastron. The fourth peripheral is 67 mm. on the free border, 
38 mm. across the lower face. Most of the upper face is broken away. An obtuse keel 
separates the upper face from the lower. The inner face of the fifth was more excavated than 
in the same bone of the type; and, as Cope states, the pit for the end of the rib is much 
smaller. 

The bones belonging to this specimen which Cope appears to have employed in his fig. 39 are 
the hyoplastron, the hypoplastron, and xiphiplastron of the right side. The figure shows 
these bones and those of the type of 0. platylomus as seen from above. A fontanel existed in 
the midline where it was crost by the hyohypoplastral suture. Where the plastral bones 
joined along the midline the sutures are coarse and jagged. The xiphiplastron sent a strong 
process into the outer border of the hypoplastron and the latter sent one outside of this mto the 
xiphiplastron. Just in front of this exchange of digitations the hypoplastron is 15 mm. thick. 
At this level the hinder lobe of the plastron was about 165 mm. wide. On the lower side of the 
hypoplastron the abdomino-femoral sulcus is seen in the position represented by Cope in his 
figure 39. "Crossing the xiphiplastron the femoro-anal sulcus falls a little further forward 
than represented by Cope in the figure quoted. 

None of the bones of this specimen is pitted. 



132 



FOSSIL TURTLES OF NORTH AMERICA. 



Osteopygis gibbi Wieland. 
Plate 26, fig. 1; plate 27, figs. I, z; text-figs. 142-146. 

Osteopygis gibbi, Wieland, Amer. Jour. Sci. (4), xvii, 1904, p. 118, plates v-viii and text-figs. 3-7. 

The type of this species is No. 783 ot the Marsh collection of Yale University. It was 
obtained from the upper bed of Cretaceous greensand, at Barnesboro, Gloucester County, 
New Jersey, in 1870. It was originally studied by Dr. George Baur (Zool. Anzeiger, xii, 
1889, p. 42), who determined from it that Cope had been in error when he stated that the 
genus Osteopygis possest 10 pairs of costal plates. Fig. I, plate 26, is reproduced from a 

drawing prepared under Baur's direc- 
tions and shows the nuchal, the periph- 
erals, and the pygal as seen from below. 
In 1904 the specimen was fully prepared 
and the parts put together under the 
direction of Dr. Wieland. A number of 
the figures made by Dr. Wieland are 
here reproduced. 

The specimen is the most complete 
that is known of any species of the family 
and it serves to give us a clear idea of 
the form and the constituents of the 
shell. It will be observed that the out- 
line of the carapace as restored by Dr. 
Baur (plate 26, fig. l) diflFers from that 
as restored by Wieland (text-fig. 142). 
Since, however, Dr. Wieland fitted the 
costals to one another and to the periph- 
erals, and brought the plastron into 
relation with the carapace, which Baur 
did not do, it is quite certain that the 
later restoration is the more accurate 
one. It can hardly be wrong except in 
small details. Fig. 143 shows the shell 
from the side. 

In form the carapace is elongated 
oval, rounded in front and somewhat 
pointed behind. It is somewhat deprest 
and especially the hinder peripherals look 
more upward than outward. The length 
in a straight line is given as 690 mm.; the 
extreme width, as about 580 mm. The nuchal bone is 127 mm. wide in front and has a maximum 
width of 145 mm. Its length is 75 mm. The dimensions of the neural bones are shown in the table. 
The eighth neural is apparently followed by a small first suprapygal. This is succeeded 
by an irregularly shaped second suprapygal, 60 mm. long and 162 mm. wide. Behind this 
comes the posterior suprapygal, which has a length of 60 mm. and a width of 97 mm. 

All the peripherals are suturally articulated with the contiguous ends of costal bones, except 
the eleventh, which articulates with the suprapygals The peripherals, except the first, second, 




Fig. 142. — Osteopygis gibbi. Carapace of type. Xj. 

C.J. I, first costal bone; m. 5. 12, twelfth marginal scute; n. i, 
first neural; n. 8, eighth neural; nu./>, nuchal bune; nu.j,nuchal 
scute; py, pygal; spy. i, .'/>y. 2, spy. 3, suprapygals. 



Neural. 

I 


Length. 


Width. 


95 


4> 


2 


65 


47 


3 


65 


47 


4 


65 


43 


S 


5o± 


37 


6 


+5± 


33 


7 


45± 


30 


8 


6s± 


38± 




-Osteopygis gibbi. 



THALASSEMYDID^. 



13.^ 







Width. 




Peripheral. 


Length. 




Thickness. 












Upper face. 


Lower face. 




I 


79 


60 




'7 


z 


82 


60 




21 


3 


75 


61 






4 


76 


60 






5 


80 


64 


42 




6 


85 


62 


4' 




7 


9Z 


Si 






8 


95 


T05 




26 


9 


93 


105 




>4 


10 


90 


1 1 1 




H 


II 


83 


110 







and the eleventh, have each a pit in the inner face to receive the end of" a rib extending beyond 
the costal plate. In the hinder peripherals these pits are flattened; also they produce notches 
in the upper face of a number of the hinder peripherals, as they do in O. borealis. This 

deficiency in the upper wall of some of the pits 
marks one difference between this species and 
0. emargtnatus, the type of the genus. The 
inner face of the second peripheral has a large 
pit for the reception of the outer anterior exten- 
sion of the hvoplastron. The inner face of the 
third, fourth, fifth, sixth, and seventh periph- 
erals is broad and longitudinally excavated. 
These bones have thus three borders, the outer, 
or free border; the upper border, which articu- 
lates with the costals; and the inferior border, 
which comes into contact with the plastron. In 
the anterior end of the eighth there is a cavit\' 
into which the outer posterior process of the 
hypoplastron projects. The inner face of the peripherals behind the eighth becomes narrow 
and curves into the lower face. Thus, these hinder peripherals are thin and wedge-shaped. 
The dimensions of the peripherals are shown in the table herewith. 

The acute free border of the hinder peripherals may be traced forward on the more anterior 
ones, where it forms a keel separating the upper face from the lower. The peripherals, from 

the seventh to the eleventh inclusive, are slightly concave on the 
upper surface. 

The pygal bone measures about 85 mm. along the free border 
and has a height of about 75 mm. 

The sulci between the various scutes of the carapace are 
rather deeply sunken. The dimensions of the vertebral scutes 
are given in the table. 

The hinder border of the fifth lies on the posterior supra- 
pygal. The supracaudals join along the midline a distance of 
70 mm. and each is 40 mm. wide. The costo-marginal sulci lie wholly on the peripheral bones, 
close to their upper margins, except at the rear, as just noted. 
There are four pairs of costal scutes. 

The surface of the bones of the carapace is usually smooth; but in places there appear 
striations, which are directed outward and backward. There are no pits. 



Vertebral. 


Length. 


Width. 
210 




no 




140 


120 




■33 


"5 




142 


■35 




.48 


180 





145- '46- 

Figs. 144-146. — Osteopygis gthhi. Plastron and limb bones of type. 

144. Plastron. Xj. ai, abdominal .scute ; on, anal scute; en(, entoplastron ; e/i/, epiplastron; /,/, median and 

posterior fontanels ; fem, femoral scute ; hyo, hyoplastron ; injmf, supposed inframargmal scute ; pec, pec- 
toral scute; xiph, xiphiplastron. 

145. Humerus, dorsal surface. Xj. 146. Femur, dorsal surface. Xj. 



134 



FOSSIL TURTLES OF NORTH AMERICA. 



Relatively to the carapace the plastron (plate 27, fig. 2; text-fig. 144) is smaller than in 
Caretta caretta. Nevertheless, the connection between the borders of the plastron and the 
peripherals is more extensive than in the genus just mentioned, extending from the second to 
the eighth peripherals. The outer anterior prolongation of the hyoplastron reaches forward 
as far as does the anterior lobe, and the outer posterior prolongation of the hypoplastron 
extends backward nearly as far as does the hinder lobe. The hyoplastron sends a process into 
the second peripheral, and the hypoplastron has its hinder prolongation inserted in an excava- 
tion of the seventh and eighth peripherals. In the fourth and sixth peripherals are small 
pits for digitations of the plastral bones. The median longitudinal suture is a coarse one. 
There is a median fontanel at the crossing of the hyohypoplastral suture and the median 
longitudinal. On each side, at the ends of the hyohypoplastral suture, is another fontanel. 
A fourth is found on the median line just in front of the xiphiplastra. 

The epiplastra are narrow bones which have a length of about 85 mm. and a width of 
15 mm. The entoplastron is only in part preserved. It appears to have been 85 mm. long 
and 59 mm. wide. 

The least width across the bridges is 1 14 mm. The hinder lobe is much reduced, leaving 
free play for the hinder limbs. The xiphiplastra are 185 mm. long and 55 mm. wide. 

The sulci of the plastron are very obscure, but Wieland appears to have mapt them 
correctly. There were quite certainly inframarginals on the outer ends of the bridges. The 
sulcus between the gular and the humeral scutes has not been observed; nor that between the 
humeral and the pectoral. Wieland calls the pectoral scutes the humerals; the abdominals, 
the pectorals; the femorals, the ventrals; the anals, the femorals. The abdominals have a 
width, at the midline, of about 65 mm.; the femorals, a width of 78 mm.; the anals, a width 
of nearly 150 mm. 

Wieland has figured the humerus (fig. 145). The total length is 145 mm.; the short 
diameter of the flattened shaft, 18 mm.; the long diameter, 21 mm. It resembles the humerus 
of Chelydra. The angle between the planes of the ulnar and radial crests is obtuse. The 
distal end of the bone is grooved, as in some species of Emydidte and of Testudinidce. The 
ectepicondylar passage is a deep perforation. The femur has a length of 150 mm., therefore is 
longer than the humerus. It resembles that of Chelydra, except that the distal end is grooved. 
In this respect too it differs from the femur of 0. borealts. 

Wieland has described and figured the ulna, the tibia, 2 metatarsals, and I cervical 
vertebra. Fig. 146, from Wieland, represents the femur. 

This species is most nearly related to the type of the genus, Osteopygts emargtnatus 
Cope. The latter differs in having the posterior peripherals emarginated on the free borders 
at the end of the intermarginal sulci, in not having the upper borders notcht so as to expose 
the end of the rib, in having a shorter first vertebral scute, and apparently in having narrower 
second and third vertebral scutes. The type of O. emarginatus is only slightly smaller than 
the type of 0. gtbbt, the nuchal of the former measuring along the front 122 mm.; that of 
the latter, 127 mm. The first vertebral scute of 0. emarginatus is close to 82 mm. long; that 
of 0. gihbi, no mm. The width of the second vertebral of O. emarginatus, at the anterior 
end, is close to 75 mm.; that of O. gibbi, about 102 mm. 

Osteopygis robustus sp. nov. 

Figs. i47-'5'- 

In the American Museum of Natural History is a lot of bones which is accompanied by a 
label written by Professor Cope, stating that they were found at Birmingham, New Jersey, 
that he regarded them as belonging to Osteopygis emarginatus, and that he received them 
November 13, 1870. Those bones which can be safely regarded as belonging to one individual 
are the nuchal, the first and second peripherals of both sides, the tenth and eleventh peripherals 
of both sides, the fourth costals of both sides, the left fifth, the left seventh and the eighth, and 
the proximal end of the right eighth. There are also fragments of other costals of unde- 
termined position. To this specimen is given the number 2360. 

A comparison of these bones with those of the types of 0. emarginatus and O. gihbt makes 
it evident that they belong to a hitherto undescribed species. The diflFerences will appear as we 



THALASSEMYDIDiE. 



135 



progress with the description. That which especially strikes one is the greater thickness of 
the bones here described, as compared with corresponding ones of 0. emarginatus and 0. gibhi. 
The three types are of nearly the same size. The dimensions of various bones are given in 
_the following table. Except the length, the dimensions of each bone are taken at the anterior 

end. The thickness of the nuchal is taken 
at the midline. The columns headed by 
I belong to O. emarginatus; those by 2, 
to 0. gibbi; those by 3, to 0. robustus. 

The nuchal bone (fig. 147) appears 
to have extended backward further in 
this than in the species with which it is 
compared above. The hinder portion 
of the bone is broken away, but the por- 
tion remaining is 80 mm. wide antero- 
posteriorly. The nuchal of 0. emargina- 
tus measured in the same place gives us 70 mm.; the nuchal of O. gibhi has a length of 75 mm. 
Fig. 148 is a section at the articulation between the nuchal and the first peripheral. 

The upper border of the first peripheral, articulating with the first costal, has a thickness 
of 10 mm. (fig. 148). The left second peripheral lacks the hinder end; and that of the right 
side has the hinder end of the inner face so eroded that it does not show the pit for the hyo- 
plastron. These peripherals articulated with the first costal. The other peripherals are 
missing to the ninth, and of these only unimportant fragments remain. The tenth and eleventh 
(fig. 149) are nearly plane above, or slightly convex. The rib-pits are flat; and that of the 



Element. 


Length . 


Height. 


Thickness. 


Nuchal ... 


I 
izz 


» 3 
IZ7 IZ5 


I 


z 


3 


I z 


3 




... 




IS 1 16 


zo 


Peripheral 1 


6^ 


79 


78 


48 


60 


60 


>9 i '7 


-,o 


z 




8z 


81 


46 


60 


60 


zo 21 


^"i 


10 




90 


89 




III 


1 10 


14 


18 


II 




»1 


90 




no 


IOO± 


. . ; . . 


•9 


Pygai 




«3 


,5 


■■ 


71 68 

1 


.. , .. 


zo 




Fig. 147. — Osteopygts robustus. Nuchal bone and first peripheral right and left, of type. Xj. 

nu. s, nuchal scute; per. i, first peripheral. 

tenth is rooft over to the articulation with the eighth costal plate with bone 7 mm. thick. It is 
possible, but not probable, that the ninth peripheral had its upper border notcht by the rib- 
pit, as it is in the case of all the hinder peripherals of O. gibbi. No rib entered the eleventh 
peripheral. This and the pygal articulated suturally with the last suprapygal. The upper 
sutural border of the pygal is 13 mm. thick. The free borders of the tenth and eleventh 
peripherals are acute. Fig. 150 represents the front end of the tenth peripheral. There are no 
indications of emarginations of the free border such as are supposed to characterize 0. emar- 
ginatus. The pygal (fig. 149) is notcht somewhat at the midline. Fig. 151 is a section thru 
the middle of the pygal. 

There are present what are regarded as the proximal and the distal portions of the left 
fourth costal; the proximal end of the right fourth; the left seventh, lacking most of the front 
border; the left eighth entire; and the proximal end of the right eighth. These bones are all 
thick. Where the suture with the neurals is shown the bone is 10 mm. or 11 mm. thick. At 
the middle of the length of the costals the sutural edges are about 6 mm. thick. The distal 
ends of costals four and five were suturally joined to the corresponding peripherals; and the 
same is true of the seventh and the eighth. The fourth costal has a width of 62 mm. at the 
costo-vertebral sulcus and 70 mm. at the distal end. The end of the rib of this costal projects 
from near the front border of the distal end, as it appears to do, likewise, in 0. gibbi. The width 



136 



FOSSIL TURTLES OF NORTH AMERICA. 



of the fifth costal at the distal end is jy mm. At the costo-vertebral sulcus the seventh and 
eighth costals (fig. 149) are each 39 mm. wide. The eighth is 47 mm. wide at the distal end. 
On the inferior side of the eighth costal is seen the base of the small rib-head. Behind this is 
the co-ossified end of the vestigial tenth rib. 

The surface of the bones of the carapace is almost everywhere more or less uneven. On 
the nuchal and the anterior peripherals the areas occupied by the scutes are tumid, and the 
sulci run in deep and broad valleys. The same remarks apply to the dorsal region of the 
carapace, so far as represented. The sulci of the distal portions ot the costals and of the hinder 

peripherals are deeply imprest. 
The upper surfaces of the hinder 
peripherals are more or less undu- 
lating. 

The nuchal scute (fig. 147) is 
smaller than that of either 0. 
emarginatus or 0. gtbht; its width 
anteriorly being 47 mm.; poste- 
riorly, 80 mm.; its fore-and-aft 
extent, 24 mm. The first marginal 
is 62 mm. along the front; 30 mm. 
where it joins the nuchal; 45 mm. 
where it joins the second marginal. 
On the tenth peripheral the costo- 
marginal sulcus runs 30 mm. 
below the upper border of the 
bone. At the midline behind, the 
sulcus crosses on the hinder supra- 
pygal. 

The anterior vertebral scute 
had a width of about 200 mm. 
On the fourth costal the costo- 
vertebral sulcus crosses the bone 
at a distance of about 44 mm. 
from the neural border. Esti- 
mating the width of the neural at 
45 mm. the width of the third ver- 
tebral would be about 135 mm. 
The fourth vertebral, at the ante- 
rior border of the seventh costal, 
appears to have been about 100 
mm. wide. That of 0. gtbbi was 




Figs, li 



151 

-151 



-Osteopygis robustus. Costals, peripherals, 
and pygal of type. 

148. Section at proximal end of first peripheraL Xj. 

149. Right seventh and eighth costals, hinder peripherals, and pvgal. xj. 

150. Section of anterior end of tenth peripheral. Xj. 

151. Section along middle of pygal. Xj. 



about 135 mm. wide. The fifth vertebral had a width posteriorly of 190 mm. Its length was 
close to 155 mm. 

On account of the common feature of sutural union of all the peripherals with the costals, 
this species needs comparison only with 0. emarginatus and O. gibhi, and such comparisons 
have already been made. 

Osteopygis chelydrinus Cope. 

Plate 23, figs. 4-7; plate 28, figs. 1-4; teit-figs. 152-154. 

Osteopygis chelydrinus, CoPE, Proc. Acad. Nat. Sci. Phila. 1868, p. 147 (nom. nud.); Geol. New Jersey, 
Cook, 1869, Append., p. 735 (nom. nud.); Amer. Naturalist, in, 1869, p. 89; Ext. Batrach.. 
Reptilia, Aves N. A., 1869, pp. 135, 138, plate vii, fig. 8.— Hay, Bibliog. and Cat. Foss. Vert. 
N. A., 1902, p. 441. 

Catapleura chelydrina. Cope, Vert. Cret. Form. West, 1875, p. 259. 

In his Synopsis of the Extinct Batrachia, Reptilia, and Aves of North America, Professor 
Cope stated that this species was represented by "only 10 marginal plates more or less perfect 
and some costals"; also that the species was referred to the genus Osteopygis because the 



THALASSEMYDID^. 



137 



"anterior rib-bearing marginal bone has been united with the middle disk by suture." In the 
Vertebrata of the Cretaceous Formations of the West he says that the reference of the species 
to Cataphura is not final, " as the anterior costals and marginals are not known. " 

Of Cope's type only a single bone was figured, the peripheral which he regarded as doubt- 
fully the tenth of the right side. In the Cope collection of fossil reptiles in the American 
Museum of Natural History this figured bone is found (plate 23, figs. 4, 5; text-fig. 152). It is 
accompanied by a number of other bones, some of which are markt in such a way that it is 
evident that Cope intended to figure them; besides other bones which probably do not belong 
to the species. It is evident that several of the bones belonging to the type have been lost, 
while it is probable that a few of other species have become mingled with it. It is certain, 
therefore, that our future identification of the species in new materials must depend princi- 
pally on the figured peripheral. The catalog number is 1131. Cope's label shows that the 
type came from Barnesboro, New Jersey. 

It is evident that the bone in question does not belong to the right side. Usually in the 
related species the pit for the rib lies nearer the hinder end of the bone and the sulcus reaches the 
upper border in front of the pit; but if this bone is assigned to the right side, this pit will lie 
nearer the front end and the sulcus will fall behind the pit. The bone appears to be the seventh 
of the left side. It resembles closely the seventh of a specimen of O. horealis, but with specific 
differences. 

Cope has given the length and breadth of this bone as being respectively 2 inches 9.3 lines 
(70 mm.) and 3 inches 2 lines (80 mm.), by length meaning evidently the distance from the 
suture with the bone in front to that with the bone behind, and by width the distance from the 
costal border to the free border. These dimensions will vary somewhat with the points selected 

[52. 




Figs. 152-154. — Osteopygis chelydrinus. Sections of peripherals of type. Xj. 

151. Section of seventh peripheral. 153. Section along intermarginal sulcus of second left peripheral. 

154. Section at front of third peripheral. 

on the borders. The free border of the bone originally measured at least 75 mm.; the 
upper border now measures 53 mm.; and the anterior border 80 mm. Cope states that 
these peripherals are remarkable for their shortness, but a careful comparison hardly confirms 
this statement. A more certain character appears to be found in the thickness of the bone. 
The thickness of the end regarded by the present writer as the anterior is slightly more than 
23 mm.; that of the other end is 19 mm. This is considerably more than the thickness of even 
the eighth peripheral of any known species, regard being had for the other dimensions. 

Another character has been noted by Cope, the angulation of the free border, at the end 
of the epidermal sulcus. The angle included between the two portions of this border is about 
130°. In other species the border is nearly straight or slightly concave where met by the 
sulcus. Usually in turtles, when the border of the carapace is notcht, the sulcus ends at the 
notch. Whether or not the angulation of the border is found in all of the posterior peripherals 
we have now no means of determining; but in all probability all were angulated. 

The pit for the extremity of the rib is elliptical in section and 29 mm. deep. The horizontal 
diameter is 15 mm.; the perpendicular, 11 mm. 

The bone may be regarded as having three faces, an upper, a lower, and an inner. The 
upper is slightly concave along a line from the costal to the free border. The epidermal 
sulcus is broad, but rather shallow. The sulci between the marginal scutes and the adjacent 
costal scutes appear to have run along close to the costal border. The lower face is consid- 
erably convex along a line from the free to the costal border. On this face there is a broad 
shallow sulcus, corresponding to the one above. The inner face contains the rib-pit. This 
face is concave and irregular, with the upper portion overhanging the lower. The bone did 
not form a sutural connection with the border of the first costal plate. 



13^8 FOSSIL TURTLES OF NORTH AMERICA. 

The second peripheral of the left side (plate 23, figs. 6, 7; text-fig. 153) measures 64 mm. 
along the free border and has a minimum width of 45 mm. From the thin costal border the 
bone thickens rapidly on the lower side until a thickness of 16 mm. is attained at the proximal 
end of the bone and of 19 mm. at the distal end. The inner half of the lower surface is a little 
concave; the outer half very convex and rising to meet the upper surface. The anterior half 
of this face looks forward. The distal end of the lower surface is deeply excavated for the 
outer anterior angle of the hyoplastron. There can be little doubt, it is believed, that this is 
the peripheral whose length and breadth Professor Cope has given respectively as 2 inches 
6 lines and i inch 9 lines. It was evidently suturally united with the first costal plate. 

The third peripheral (plate 28, figs. I, 2; text-fig. 154) of the right side is present. It has 
an extent of 61 mm. along the free margin and 42 mm. at right angles with this. It presents 
three faces, an upper, an inner, and a lower. The inner face is concave and is to a great extent 
occupied by an excavation for the reception of the rib of the first costal plate. Its width is 42 
mm. where widest. It is separated from the lower face by a sharp ridge. 

The upper face is nearly plane except in front where it rises to the summit of a ridge, 
on which it joins the lower face. A sulcus crosses this face nearer the proximal end. Its hinder 
border is grooved by the sulcus between the marginal and the first costal scute. The maximum 
width of this face is 34 mm. The lower face is quite convex vertically, the upper portion of it 
looking upward and forward, the remainder downward and forward. Its width is 23 mm. 
What distinguishes these anterior peripherals especially is the carina where the upper face 
meets the lower. 

Accompanying the bones above described is the lower jaw of a turtle, consisting of the 
united dentaries (plate 28, figs. 3, 4). This has written on it, doubtless by Professor Cope, the 
name "chelydrinus. " It is hardly conceivable that he would not have mentioned this jaw had 
it been present when he described the other bones. It is difficult to understand why he should 
have referred it to this genus and species without some good reason, when it would naturall}' 
have been placed in his genus Lytoloma. It is possible that he discovered after his description 
had been publisht that it belonged with the type of 0. chelydrinus, yet he does not mention 
the lower jaw in his reference of the species to Catapleura in 1875; but he does give, under 
the genus Osteopygis, a description of the lower jaw, which description might have been based 
on the jaw now under consideration; and no other jaw is known which has been referred to 
Osteopygis. The matrix clinging to the jaw is exactly like that on the peripherals. The 
matter is very obscure. 

This jaw resembles that of Lytoloma angusta, but there are at least specific differences. 
Figures of it are here presented. In the jaw called "chelydrinus" the outline is almost that of 
a semicircle whose center lies a little behind the posterior end of the symphysis and whose 
radius is 38 mm. In Lytoloma angusta the outlines of the jaw run in nearly direct lines from 
the front of the masseteric fossa to near the tip of the jaw. In the jaw "chelydrinus" a line 
joining the mental foramen, lying in the front of the left masseteric fossa, with that of the 
right side tails at or a little behind the posterior end of the symphysis. In the type of Lyto- 
loma angusta the same line falls in front of this end of the symphysis a distance equal to 
one-sixth the whole length of the symphysis. In "chelydrinus" the symphysis forms 47 per 
cent, of the width of the jaws at the front of the masseteric fossae; in Lytoloma, 58 per cent. 
It is quite evident, therefore, that the jaw labeled "chelydrinus" represents a species distinct 
from Lytoloma angusta. It differs fully as much from the jaw figured by Wieland under the 
name Lytoloma angusta, here described as Lytoloma wielandi. 

Osteopygis erosus Cope. 
Plate 26, Sg. 2; text-figs. 155-162. 

Osteopygis erosus. Cope, Vert. Cret. Form. West, 1875, p. 258. — Hay, Bibliog. and Cat. Foss. Vert. N.A., 
1902, p. 441. J 

The type of Cope's Osteopygis erosus is now in the American Museum of Natural History 
and bears the number 1 130. The specimen appears to have been discovered in the upper bed 
of Cretaceous greensand, at Barnesboro, New Jersey, in 1869. It was probably found too 
late for inclusion in the monograph of 1869 and was reserved for publication until 1875. The 



THALASSEMYDID^. 



139 




Fig. 155. — Osteopygis i-rosus. 

First and second peripherals and first costal of type. 
X§. First peripheral at the right. 



type specimen comprises all the peripherals of the left side, except the third, fourth, fifth, and 
eleventh; the second, fourth, eleventh and half of the ninth of the right side; the first left 
costal, lacking the distal end; the distal end of the first right costal, and many fragments of 
other costals; two neurals and a portion of a suprapygal; some fragments of the plastron; 
and two vertebrae. Cope mentions five vertebrae. 

An estimate, based on the dimensions of the peripherals, shows that the carapace was 

probably slightly shorter than that of the type of 
O. gibbi; that is, it was about 740 mm. long in a 
straight line. 

Professor Cope stated that this species is 
abundant in the upper bed of Cretaceous green- 
sand at several localities in New Jersey, but the 
present writer knows of but one other specimen. 
The nuchal bone is missing, but its form and 
proportions were probably similar to those of the 
nuchal of 0. emargmatus. The following table 
presents the dimensions of the peripherals (plate 
26, fig. 2; text fig. 155). The length is taken 
along the free border. The height is the distance 
at the anterior end of the bone, from the free 
border to the costal border. The thickness is the 
greatest taken at the anterior end of the periph- 
eral. Where a definite inner face presents itself, 
as from peripherals 4 to 8, the thickness is 
replaced by the dimensions of these faces. The 
dimensions of the hinder end of any bone are the same as the dimensions of the front end of 
the succeeding bone. 

The free borders of the first (fig. 156) and second (fig. 157) peripherals are thick and 
obtuse. On the fourth there is a subacute, slightly upturned free edge, which may be traced 
forward as an obtuse keel, even to the first peripheral. On the fourth peripheral (fig. 158) 
the upper and the lower faces form an angle with each other greater than a right angle; but on 
the sixth (fig. 159) this is already less than a right angle; and more posteriorly the two faces 

become more nearly parallel (figs. 160, 
161). The upper faces of the four ante- 
rior peripherals are irregularly convex; 
those of the sixth and seventh are some- 
what concave; those of the others are 
nearly plane. 

In the hinder end of the second 
peripheral (fig. 157) is a deep pit for the 
anterior prolongation of the hyoplas- 
tron. Cope thought that this pit was 
for the rib-end of the first costal. The 
pits in the greater number of the periph- 
erals are circular in section. Those of 
the ninth, tenth, and eleventh are flat- 
tened. In the last^mentioned cases the pits produce notches in the upper faces of the periph- 
erals. The anterior end of the inner face of the eighth peripheral is deeply excavated for the 
posterior outer angle of the hypoplastron. The inner face of the seventh is considerably 
excavated for the same purpose. Several shallow pits appear along the lower borders of the 
inner face of the sixth and seventh peripherals for digitations of the plastron. There was no pit 
in the eleventh peripheral. This bone had a thickness of 18 mm. where it joined the pygal. 
As regards the connection of the peripherals with the costals, we appear to have the fol- 
lowing: The first and second peripherals were closely sutured with the first costal. The distal 
end of this costal shows that at least the anterior half of the third peripheral was sutured with 
it. The anterior end of the upper border of the fourth costal is smooth; the posterior two- 



Peripheral. 


Length . 


Height. 


Thickness. 


Width. ' 






I 


83 


61 




Lower face. 


Inner face. 


21 


1 


8i 


62 


^3 






3 




5' 


3' 






4 


78 


53 




?8 


63 


5 




64 




43 


68 


6 


83 


65 ± 




57 


47± 


7 


85 


76 




57 


46 


8 


94 


9^ 




80 


3' 


9 


98± 


IOO± 


18 






10 


95 


97 


•7 


■■ 




II 


90± 


io5± 


'7 








140 



FOSSIL TURTLES OF NORTH AMERICA. 



thirds is rough, indicating sutural union with the second costal. Probably the sixth peripheral 
was free from union with a costal; also the seventh. The hinder portion of the border of 
the eighth peripheral is rough, as if it had formed a suture with the contiguous costal. The 
upper borders of the succeeding two peripherals are broken away, so that we can not determine 
their mode of connection with the costals. The eleventh peripheral articulated suturally with 
the suprapygals. 

The first costal bone (fig. 155) has an extreme width of 104 mm. The outer end of its 
rib was inserted in the third peripheral. In front, where it articulated with the nuchal, it is 
10 mm. thick and the suture is beveled in a manner to show that the nuchal slightly overlapt 
the costal. The hinder border is 9 mm. thick. Another costal has a width of 72 mm. and a 
thickness of 10 mm. The rib is not conspicuous on the under side. 

The two neural bones are probably the third and fourth (fig. 162). Measured along the 
midline the bone anterior is 84 mm. long, while the width is 42 mm. The anterior end is 
narrowly notcht for the reception of the preceding neural. There is no definite angle between 
the antero-lateral and the postero-lateral sides. The other neural is 61 mm. long and 40 mm. 
wide. 

The sulci which mark the boundaries of the horny scutes are extremely distinct, becoming 
sometimes deep and broad. The outer end of the first marginal is 46 mm. wide. The second 




Figs. 156-162. — Osteopygis erosus. Portions of shell of type. No. 1 130 A. M. N. H. 



156. Section of first periplieral. X5. 

157. Hinder end of second peripheral. 

pit for process of hyoplastron. 

158. Section of fourth peripheral. X| 



159. Section at anterior end of sixth peripheral. X3. 
Xjf. Shows 160. Section at middleof length of eighth peripheral. Xjf. 

161. Hinder end of tenth peripheral. XJJ. 

162. Two neurals. xj. 



extends from the free border 55 mm.; the third, 41 mm. Behind this, the costo-marginal 
sulci run along on the upper borders of the peripherals. From the upper borders of the 
eleventh peripheral the sulcus crost on the last suprapygal, not coming into contact with the 
pygal. The first vertebral scute appears to have been as in 0. emarginatus. Its width can 
not be determined. 

All the bones of the carapace are more or less rough and uneven, but that which especially 
distinguishes them is the presence of numerous pits. These vary in size, depth, and distri- 
bution. The average diameter is about 5 mm. These pits are relatively few on the anterior 
portion of the carapace. They are numerous on the costals, and present commonly on the 
peripherals (plate 26, fig. 2). 

The fragments of the plastron furnish no useful information, 

Accompanying the bones are a scapula and an ilium. The upper end of the scapula 
and the distal end of the procoracoid process are broken off. The remainder of the bone 
resembles the same bone in Caretta caretta. The ilium is broader and flatter above than in the 
genus just named. 



THALASSEMYDID^. I4I 

Osteopygis borealis (Wieland). 

Plate 26, fig. 3; text-figs. 163-171. 

Osteopygis sopita, CoPE, Proc. Acad. Nat. Sci. Phila. 1868, p. 147; Vert.Cret. Form. West, 1875, p. 258. — 

Hay, Bibliog. and Cat. Koss. Vert. N. A., 1902, p. 441. 
Propleura sopita, CoPE, Cook's Geol. New Jersey, 1868 (1869), p. 735; Amer. Naturalist, III, 1869, p. 88; 

Ext. Batrach., Rept., Aves N. A., 1869, pp. 140, 235, p. vii, figs. 4-7, text-fig. 39. 
Propleura borealis, Wieland, Atner. Jour. Sci., (4) xvii, 1904, p. 129, pi. ix; ihid, xviii, 1904, p. 190, 

fig- 4- 

Under Osteopygis sopitus the writer has presented his reasons tor concluding that Cope 
erred when he referred to that species the specimen of Osteopygis which he described in his 
Extinct Batrachia, etc., p. 140, plate vii, figs. 4-7. 

The type of Wieland's Propleura borealis is No. 778 of the Marsh collection, in the Yale 
University museum. It was obtained in 1870, from the upper bed of greensand, near Horners- 




FlG. 162.— Osteopygis borealis. The humerus, and parts of carapace, plastron and pelvis. X J. 

c p I, c.«. 2, etc., costal plates; Aum, humerus ; Ajo, hyoplastron ; A>/>o, hypoplastron ; ;7, ilium ; mcA, ischium; 
n.l,n,2, first and second neurals; nu.p, nuchal plate; /.«*, pubis; xifih, x.phiplastron. I, 2, 3, etc., right 
and left peripherals. 

town, Monmouth County, New Jersey. It furnishes the nuchal and the first and the second 
neural; the second, third, fifth, sixth, and seventh right peripherals; the first, second, 
third, fifth, and sixth left peripherals; the first, second, fourth, and filth right costals; the first 
and second left costals; the right hyoplastron and hypoplastron; both xiphiplastra; the 
left humerus; the left pubis and ilium; and both iha. These bones are in a fine state of 
preservation. 



142 



FOSSIL TURTLES OF NORTH AMERICA. 



Wieland suggested that his type might prove to belong to 0. erosus. However, the latter 
differs in having thicker bones and a longer nuchal. To illustrate this statement we will 
consider the seventh peripheral. The length of this is 88 mm., just three-fourths that of the 
same bone in the type of borealis, yet the thickness of the inner face is 47 mm.— 7 mm. more 
than in the latter species. This is too great to be due to age or individual variation. The 

length of the nuchal in borealis is 90 
mm. This bone is not present in the 
type of erosus, but the left peripheral 
and first costal show that it extended 
backward at least 90 mm., and it cer- 
tainly was still longer. If the animal 
had grown to be a fifth or a fourth 
larger the nuchal would have been 
much more than 90 mm. in length. 
The anterior peripherals of O. erosus 
are higher than those of the type of 
borealis, altho the latter belonged to a considerably larger individual. 

On comparing the bones of borealis with those of Cope's supposed sopitus in the 
American Museum of Natural History no important diiferences are observed. The nuchals 
agree. The surface of borealis is marked by pits resembling rain-drop impressions; but the 
surface of Cope's specimen is so markt to some degree, and a larger specimen referred to the 
species has such impressions in abundance. Some differences do appear, when careful compari- 
sons are made among the measurements of the peripherals, but these fall within a few 
millimeters. Greater differences may be observed between other specimens which are regarded 
as belonging to 0. borealis. Figures and measurements are presented above of various parts 
of Wieland's specimen. A portion of these are taken from Dr. Wieland's paper, but most 
of them have been kindly furnisht me by the author. 

Fig. 163 is redrawn from Wieland's figure in the American Journal of Science and reduced 
by one-fourth making the figures one-eighth the size of nature. 



PeripheraL 


Length. 


Height. 


Thickness. 


Width. 


Lower face. 


Upper face. 


2 
3 
4 
5 
6 

7 


103 
95 

75 

90 
104 
..0 


60 
60 

45 

58 
68 
80 


»3 
28 


40 

40 
60 


45 

'5 

50 

*° 1 




Figs. 164-168. — Osteopygis borealis. Peripherals of type. Xj. 



164. First left peripheral, with section (164/3) of the 

proximal end. In the section the upper surface 
is directed toward the left. 

165. Anterior end of third peripheral. 



166. Anterior end of fifth peripheral. 

167. Anterior end of sixth peripheral. 

168. Anterior end of seventh peripheral. 



Fig. 164 presents the first left peripheral from above, together with a view of the end 
which joins the nuchal bone; figs. 165, 166, 167, and 168 represent the anterior ends respect- 
ively of the third, fifth, sixth, and seventh right peripherals. 

The length of the first neural is 102 mm.; its greatest width is 55 mm. The first costal 
has a maximum width of about 120 mm. The second is 90 mm. wide at the costo-vertebral 
sulcus. The first vertebral scute is about 285 mm. wide; the second, about 180 mm. 

The plastron (fig. 163) in general resembles that of 0. gibbi; but the fontanels appear to 
have been larger and the bridge was wider. The latter has a width of 138 mm. The whole 
plastron had a width, taken across the hypoplastra, of about 520 mm. The hyoplastron 
extended forward from the hyohypoplastral suture 138 mm. 



THALASSEMYDID^. 



143 



The humerus (fig. 163, hum) has an extreme length of 170 mm. The shaft dorso-ventrally 
is 17 mm. thick. The smooth rounded end is 54 mm. wide. The ulnar crest rises ahove the 
head. Between the plane of the two proximal processes the angle is obtuse. 
The pelvis (fig. 163 11, isch, pub) resembles in general that of Chelydra. 
The specimen referred to above as having been described by Cope as Osteopygis sopitus 
is now in the American Museum of Natural History and has the number 2351. It consists 
of peripherals one to four, seven, eight, and ten, of the right side; peripherals one, three to 
five, seven, eight, and ten, of the left; the nuchal, the proximal portions of costals one to 
four of the left side; one nearly complete costal, perhaps the third of the right side; many 
fragments of other costals; a number of plastral bones; parts of both humeri; and a complete 
left femur. 

Cope has, from this specimen, produced a figured restoration of the carapace (Ext. Batr. 
Rept., etc., p. 139, fig. 39). This is represented as having 10 pairs of costal plates and a corre- 
sponding number of neural bones. It is difficult to understand how that author could suppose 
that the rib of the first costal could extend far enough forward to enter the pit in the second 
peripheral. Evidently he saw no other possible use for the pit. The eleventh peripheral is 
not present. On the tenth is found the number "10," written in ink; but at that time the 
right hand digit "o" was written upon a "i." Altho on page 235 of the work cited. Cope 
concluded that the genus Osteopygis had only nine pairs of costals, he maintained, from exami- 
nation of the present specimen, that Propleura had ten pairs. Nevertheless, in his Vertebrata 
of the Tertiary, publisht in 1884, he stated that Osteopygis had 10 pairs and Propleura 9 pairs. 

Cope figured a part of the nuchal, 
the first left peripheral, and a part of 
the first left costal. They are refigured 
(fig. 169, p. 145), with the addition of 
fragments overlookt by Cope. The 
front of the carapace, along the nuchal, 
was somewhat concave. The free bor- 
ders of the nuchal and the anterior per- 
ipherals are obtuse and thick. At the 
midline the nuchal is 10 mm. thick. 
The fore-and-aft length of the nuchal 
is 78 mm. ; its width along the free bor- 
der was close to 120 mm. The border 
which joined the first neural is only 5 
mm. thick. The table gives the dimensions of the peripherals, the measurements, except 
the lengths, being taken at the anterior ends. In a few cases a dimension has been taken 
from the contiguous end of the peripheral in front. 

The first peripheral was suturally joined to the first costal; probably also the second, but 
the border is missing. It is probable that all the other peripherals to the eleventh were free 
from the contiguous costals, but the upper border of the fifth has some appearance of having 
formed a suture. The upper faces of the anterior peripherals are nearly plane. Beginning with 
the fifth, the upper faces are more or less concave from the free edge to the costal border. The 
hinder peripherals have a thin acute border and this may be traced foi-ward, but becoming less 
acute, to the first peripheral. In the hinder end of the second peripheral, in the inner face, is a 
pit, like a deep thumb impression, for the anterior prolongation of the hyoplastron. The other 
peripherals have each a pit for the end of the corresponding rib. They are at the middle of the 
length of the inner face. Most of them are circular in section, but those of the last two or three 
peripherals are somewhat flattened; and they notch the upper face of the bone. 

The first costal has a maximum width of 98 mm. The second is 66 mm. wide; the third, 
60 mm.; the fourth, 46 mm., all measured at the costo-vertebral sulcus. At the sutural 
borders these bones are 5 mm. thick. 

The surface of most of the bones is more or less roughened; and on many ot them, espe- 
cially the costals, there are present scattered pits, each about 3 mm. in diameter. These pits 
are less conspicuous on the hinder peripherals. 



Peripheral. 


Length. 


Height. 


Thickness. 


Width. 














Lower face. 


Inner face. 


I 


77 


43 


1 'i 




z 




40 


18 




3 


70 


32± 




29 3o± 


4 


73 


36 




29 40 


S 


75 


47 




34 43 


6 




SO± 




48 : 3o± 


7 


92 


65± 




57 ! ^* 


g 


90 




16 




9 






10 


" 


10 


87 


gg 


'0 

1 





144 



FOSSIL TURTLES OF NORTH AMERICA. 



The area of the scutes of the carapace is distinctly markt. The nuchal scute measures 
58 mm. along the free border; 90 mm. along the posterior border. Fore and aft it is only 20 mm. 
The first vertebral had a width of about 200 mm. Its length was 100 mm. The second vertebral 
was 100 mm. wide and 150 mm. long. Behind the first peripheral the costo-marginal sulcus 
ran along the unossified space between the costals and the peripherals. 

The plastron evidently had the form presented in 0. gibbi. The piece of the bone consid- 
ered by Cope as the epiplastron is the anterior outer end of the hyoplastron. At the axillary 
notch the hyoplastron had a thickness of 1 1 mm. At the inguinal notch the hypoplastron was 
14 mm. thick. As in the other species, there was an interchange of digitations between the 
hypoplastron and the xiphiplastron. 

Cope figured the right humerus. This bone lacks the head, both trochanters, and a little 
of the distal end. The original length must have been close to 120 mm. The radial and the 
ulnar crests made apparently something more than a right angle with each other. The shaft 
is bent and flattened. The dorso-ventral diameter is 13 mm.; the horizontal diameter, 19 mm. 
The width of the distal end is 38 mm. The femur is practically complete. The extreme 
length is 132 mm. The bone resembles closely that of Chelydra. The planes of the tibial and 
the fibular crests make a right angle with each other. The diameter of the shaft is 14 mm.; 
that of the distal end, 36 mm. 

In the American Museum of Natural History are portions of a large individual which is 
referred to this species. There are present peripherals 7 to 1 1 inclusive of the left side, periph- 
erals eight, ten, and eleven of the right side, and a considerable part of the hindermost 
suprapygal. With these are other bones, some or all of which may belong to another individual, 

possibly to another species. These con- 
sist of 2 complete costals, 3 neurals, the 
left hyoplastron lacking the inner end, 
the left hypoplastron lacking a small 
portion of the outer end, and a femur. 
Besides these, there are parts of first, 
second, and third suprapygals that can 
not belong to the same individual as 
did the peripherals. All these bones 
are included under the number 1132. 
This is the specimen mentioned by Cope (Ext. Batr., Rept., etc., p. 142) as having been 
found at Hornerstown, Monmouth County, New Jersey. 

The peripherals (plate 26, fig. 3) indicate a large individual, with a carapace about 825 mm. 
long. The dimensions of the peripherals are given in the table above, the measurements 
being taken as in the case of the type specimen. 

The pits for the rib-ends entering the hinder three peripherals are flattened, as in the No. 
2351, and similarly they notch the upper face of the bones. None of the peripherals present 
was suturally articulated with the costals, but the eleventh was sutured with the hindermost 
suprapygal. The latter had a length of about 75 mm. and a width of 180 mm. It was there- 
fore quite different from that of 0. gibbi. 

A fragment that must have belonged to another individual presents the first, second, and a 
part of the third suprapygals, and a part of the eighth costal. The first suprapygal is about 
40 mm. long and the width is the same. The second suprapygal has a length of 45 mm. and 
a width, along the nearly straight hinder border, of about 130 mm. Of the third there is only 
a small piece. The first suprapygal is crost by the sulcus between the fourth and the fifth 
vertebral scutes. 

One of the costals is probably the third of the right side. It has a length, over the curve, of 
about 275 mm., not including the projecting rib-end. The breadth near the proximal end is 
87 mm.; near the distal end, about 95 mm. The thickness at the sutural edges is 7 mm. The 
distal end had not been sutured with the peripherals. Articulated with this costal is a neural, 
probably the third. Its length originally was about 90 mm.; its breadth anteriorly is 58 mm. 
The posterior end is narrowed and rounded. The costal and this neural supported portions 
of the third and fourth vertebral scutes. The fourth, at the hinder border of the costal, had a 
width of about 140 mm.; the third was apparently slightly narrower. 



• 








Width. 


PeripheraL 


Length. 


Height. 


Thickness. 
















Lower face. 


Inner face. 


7 


■13 


78 




67 


44 


8 


114 


93 


90 


14 


9 


106 


103 


17 






10 


I OS 


117 


16 






II 


95± 


no 


16 







THALASSEMYDID^. l^C 

All the bones of the carapace here described are plentifully furnisht with pits. These vary 
in size from I to lo mm. in diameter. That some of them are not the result of disease or 
parasites can hardly be affirmed, but they must have been produced during the life of the 
individual. 

The plastron may not have belonged to the individual that furnisht the peripherals; but 
the size befits it. In form it agrees with that of O. gibhi. At the narrowest portion of the 
bridge the hyoplastron and hypoplastron are each 67 mm. wide. As nearly as can be deter- 
mined, the width of the plastron from side to side was about 480 mm. There was evidently 
a fontanel inclosed by the two plastral bones mentioned and the peripherals. There was 
another at the crossing of the median and the hyohypoplastral sutures. There was probably 
still another at the midline just in front of the xiphiplastrals. 

The thickness of the bones at the bridge is 20 mm. 

The femur lacks the distal end. In form it resembles that of supposed 0. sopitus, as 
figured by Cope; but the size is greater. The diameter of the shaft is i8 mm. 

No. 2216 of the American Museum of Natural History comes from some unknown locality 
of the Cretaceous greensand of New Jersey, and forms a part of the Cope collection. It 




Figs. 169-171. — Osteopygis horealis. Portion of carapace and lower jaw. 

169. Front of carapace of specimen regarded by Cope as 0. sopitus. No. 2351 A. M. N. H. c. p. j, first 

costal plate; nu. />, nuchal plate; nu. j, nuchal scute; /ffr. i, first left peripheral. XJ 

170. Lower jaw, seen from above. No. 2216 A.M.N.H. X^ 

171. Section along symphysis of same jaw. Xi 

is referred confidently to the present species, altho some differences may be observed. 
It furnishes peripherals three, four, six to ten of the left side, five and eight of the right side; 
the eleventh of one side or the other; the outer end of the left hypoplastron; and a large part 
of the lower jaw. The latter is here described and figured. 

Fig. 170 represents the jaw as seen from above. Fig. 171 is a section along the symphysis. 
The length of the symphysis is 62 mm. The thickness at the hinder end of the symphysis 
is 18 mm. This is gradually reduced forward. The symphysis extends backward about 9 mm. 
behind the line joining the mental foramina. The width at the mental foramina is 92 mm. The 
crushing surface is broad and flat, rising at the sides to the cutting-edges. For a distance of 
about 32 mm. from the tip the cutting-edges are acute and are directed outward; they then 
become obtuse, as is shown by section. There certainly was no upturned beak at the tip of the 
jaw. Along the inside of the rami and behind the symphysis is a deep groove. The lateral 
halves of the jaw are solidly co-ossified, but there remain distinct traces of the suture. 

Osteopygis horealis differs from 0. emarginatus, O. gibbi, and 0. robustus in not having 

the peripherals between the second and the eleventh joined by suture with the distal ends of 

the costals. From 0. erosus it differs in having bones of much thinner and lighter construction. 

The anterior peripherals are, relatively to their length, of less height. In 0. horealis the pits for 

10 



146 



FOSSIL TURTLES OF NORTH AMERICA. 



the ribs notch both the upper and the lower faces of" the peripherals behind the seventh; in 
O. erosus they notch only the upper borders. 

0. platylomus differs in having the anterior peripherals higher in proportion to their 
length and in having the upper border of the first and second thicker. In O. platylomus the 
rib-pits of the sixth and seventh peripherals are decidedly flattened; in 0. borealts they are 
conical. O. chelydrinus differs in having the free border of the hinder peripherals angulated. 

Osteopygis platylomus Cope. 

Figs. 172-180. 

Osteopygis platylomus. Cope, Amer. Naturalist, iii, 1869, p. 89; Cook's Geo!. New Jersey, l868 (1869), 
p. 735; Ext. Batrach., Reptilia, Aves N. A., 1869, pp. 135, 137, and p. ii, figs. 38, 39; Vert. Cret. 
Form. West, 1875, p. 258. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 

The type of Cope's Osteopygis platylomus is a fragmentary specimen which belongs to the 
Academy of Natural Science of Philadelphia. It was presented to that institution by Samuel 
Ashhurst, having been discovered in the uppermost greensand bed of the Cretaceous, at Pem- 
berton, Burlington County, New Jersey. It now consists of the anterior half of one neural, 





Figs. 172 and 173. — Osteopygis platylomus. Portions of type. 
172. Part of a neural. X§. 173. Pygal, suprapygal, and tenth and eleventh peripherals. X^. 

most of the suprapygal, a portion of the nuchal, wholes or parts of all the peripherals of the 
right side, except the fifth, wholes or parts of the first, third, sixth, eighth, ninth, tenth of 
the left side, many fragments of costals and portions of the plastron. It appears that a few 
parts have been lost since Cope described the specimen. 

Cope estimated the length of the carapace at 2 feet 2 inches. The writer regards the length 
as having been close to 30 inches or about 750 mm. 

The fragment of neural (fig. 172) is crost by a sulcus and is therefore probably either 
the third or the fifth. It is deeply notcht in front for the preceding neural, and this notch gives 
evidence that the neural was not the first one. The greatest width of the bone is 56 mm. 

The bone described by Cope as the " posterior vertebral " is really the suprapygal. Only a 
portion of the left end of the nuchal remains. It is articulated to a portion of the first left 
peripheral. The free edge is obtuse and at the suture with the first peripheral the thickness is 
17 mm. The bone extends backward from the free border a little more than 60 mm., to 
articulate with the first costal. Here the thickness is only about 6 mm. The first marginal 
scute occupies the outer end of the nuchal and the anterior end of the first peripheral. Along 
the free border it is 58 mm. and it extends backward from the free border of the bone ^7, mm. 
Cope states that the nuchal scute was confluent with the first vertebral; but the writer regards 



THALASSEMYDID^. 



H7 









Width. 


Peripheral. 


Length 
free border. 


Height 

at sulcus. 




Lower face. 


Inner face. 


, 


7' 


5^ 


9 


S3 


2 


75 


49 


'5 


47 


3 


7° 




17 


37± 


4 


73 




29 


37 ± 1 


5 










6 


86 


5' 


41 


37 


7 


88 


58 


50 


»9 


8 


90 


68 


65 


20 


9 


88 


5^ 


64 




lO 










II 


80 


95 







this as a mistake. After passing about 6 mm. the sulcus between the nuchal scute and the 
first marginal, the sulcus between the nuchal and the vertebral scutes suddenly becomes very 
shallow, but the writer believes that it continues on in its usual position. 

A considerable part of the suprapygal (fig. 173) is missing. Cope's statement that it is 
only 2 inches and 4 lines wide is an error or meant to apply to some other bone. The bone in 
question is at least 1 10 mm. wide. It occupies an area that in 0. gibbi is occupied by two bones, 

but a close examination shows a line running 
from the upper angle of one eleventh peripheral 
to that of the opposite side, along which 2 bones 
have co-ossified. The angulation of the upper 
border of the eleventh peripheral shows that 
there were two suprapygals. It is probable that 
the sutural edge oftheeleventh peripheral joined 
the anterior suprapygal instead of the eighth 
costal plate. The dimensions of the peripherals 
are shown in the table. 

The sixth peripheral (figs. 174,175) presents 
three faces, an upper concave, a lower convex, 
and an inner irregular. The upper and lower 
faces meet at the acute free border. In the 
inner face is a large, somewhat flattened pit for the end of a rib. Its mouth occupies one- 
half the length of the face. Along the lower border of the face are two or three shallow pits 
for digitations of the hypoplastron. 

As we proceed forward from the sixth peripheral the free border becomes less acute, 
until, on the third, it is obtuse and the upper, now convex, face rounds into the lower. On the 
second and first peripherals (figs. 176, 177) the lower face becomes the obtuse free border 

of the bones. The inner faces of 
the fourth and the third contain pits 
for the corresponding rib-ends. The 
inner face of the second has a large 
excavation which received the anterior 
outer process of thehyoplastron. Fig. 
176 represents the first, second, and 
third peripherals of the right side. 
The upper border of the first and 
the anterior half of that of the second 
peripheral had a sutural articulation 
with the first costal (fig. 176). The 
thickness of these borders is 6 mm. 
The hinder half of the upper border 
of the second and the upper borders of all the other peripherals to the eleventh are smooth. 
The upper border of the eleventh appears to have articulated with the suprapygals, as 
already stated. 

Passing backward from the sixth peripheral, the upper and lower borders of all the 
peripherals broaden and become flatter. The inner face narrows, and finally on the eighth 
(figs. 178, 179) and succeeding peripherals, curves into the lower face. Each of these periph- 
erals, except the eleventh, has a pit for a rib-end. The hindermost peripherals are thin, the 
ninth being 14 mm. thick, the eleventh about 10 mm. The flattening of the rib-pits begins with 
the sixth peripheral. The pygal is represented by fig. 173. Fig. 180 shows one lateral border. 
There are present many fragments of costal bones, but no complete costal. The remains 
seem to show that the carapace was rather flat. The thickness of the costals near the neurals 
was about 6 mm.; near the distal ends, about 5 mm. The rib-heads were strongly developt. 
Distally, each rib projected beyond the costal and entered the pit in a corresponding periph- 
eral. The edges of the costal plates approacht closely the upper borders of the peripherals. 
On the proximal ends of two costals the costo-vertebral sulci run along about 35 mm. from 
the neural border. Another fragment shows that the vertebral scute was strongly angulated 




Fig. 174. — Osteopygis platylomus. Sixth left peripheral 
of type. Xj. 

a, from above; 6, hinder end; c, anterior end. 



148 



KOSSII, TURTLES OF NORTH AMERICA. 



laterally. The distal end of" a costal bone is 70 mm. wide. The surface of the bones is usually 
moderately smooth, but markt by irregular, rather straight, vascular grooves. The sulci are 
usually quite distinct. 

The nuchal scute is present, as stated. Its lateral extent is conjectural; the fore-and-att 
width is about 30 mm. The widths of the vertebral scutes can not be exactly determined; 
but thev all appear to correspond closely to those of O. gtbbi Wieland. The first evidently 





.76 






177- 



.78. 




179. 




Figs. 175-180. 



-Osteopygis platylomus. 
Type. Xj. 



Peripherals and sections. 



175. Sixth, seventh, and eighth right peripherals. 

176. First, second, third, and fourth right peripherals. 

177. Sections of first and second left peripherals, a, distal end of second; h, 
proiimal end of second; c, near proximal end of first. 

178. Hinder end of eighth peripheral. 

179. Front end of eighth peripheral. 

180. Section along right articular border of the pygal. 

extended laterally to about the middle of the first peripheral. The 
eleventh reacht laterally the hinder border of the pit for the last rib. 
The costo-marginal sulci run along on the upper borders of the first and second peripherals, 
then disappear, to reappear on the upper borders of the eighth to the eleventh. From the 
third to the eighth peripherals the sulci occupied doubtless the space between the costals and 
the peripherals. 

At present there remain of the plastron only a part of the left hyoplastron, most of the left 
hypoplastron, and most of the right xiphiplastron. The plastron seems not to have differed 
in any important way from that of 0. borealis. Evidently there was a fontanel between the 
hyoplastra in front and the hypoplastra behind. At the narrowest part of the bridge the hypo- 
plastron is 58 mm. wide. The thickness at the inguinal notch is 16 mm. No sulci are to be 
seen on these bones, except a faint one near the base of the xiphiplastron. To the present 
writer it seems evident that the bones on the right of Cope's figure of the plastron of this species 



THAI.ASSKMYDID^. 



149 



have been taken from the plastron of one of the specimens described by him as 0. emarginatus. 
Remarks on this specimen are made under the last-named species. In Cope's figure of the 
plastron the hyoplastron on the left side of the drawing is placed too horizontally. The anterior 
outer angle ought to be directed strongly forward. This species resembles O. borealis. For 
differences see under the latter species. 

Osteopygis sopitus Leidy. 

FiG;s. 181-184. 

Chelone sopita, Leidy, Smithson. Contrib. Knowl., xiv, 1865, pp. 104, 119. — Maack, PalKontographica, 

XVIII, 1869, pp. 238, 283. , 

Osteopygis sopitus, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441 (in part). 

The type specimen of the present species has not hitherto been figured. It belongs to the 
New Jersey State collection and is at Rutgers College, New Brunswick, New Jersey, where 
the writer has examined it. This type consisted of 4 peripherals, but Leidy was uncertain 
whether or not they belonged to one individual. These bones had been obtained in the 
Cretaceous greensand at Tinton Falls, Monmouth County, New Jersey, probably in the upper 
bed. Other specimens, which were mentioned by Leidy in his description of this species and 
figured, were afterwards referred by Cope to Lvtoloma angusfn, and probably correctly so. 




Figs. 181-184. — Osteopvgis sopitus. Peripheral of type. 

181. Seventh.^ peripheral, with section. 

182. Hinder peripheral, with section (i8i<j). The interrupted lii 
section indicates the depth of the pit. 

185. Hinder peripheral. 
184. .Section of a periplierai. 

Other specimens were referred b\' Cope to Leidy's species. One ot these had been 
secured at Harrisonville, Salem County, New Jersey, in a sort of limestone. This specimen is 
now in the American Museum of Natural History and has the number 2361. Almost certainly 
it is not a species of Osteopygis, and it has in the present work been referred provisionally 
to Rhetechelys platyops (Cope). 

The four peripherals of the type belonged behind the bridges. Figures taken from three 
of these are here presented. Fig. 181 represents in outline one which is regarded as being the 
right seventh. It is 115 mm. long, 59 mm. wide near the anterior end, 20 mm. thick at this end, 
and 12 mm. at the posterior end. There are 3 faces — an upper, a lower, and an inner, or 
visceral. The pit for the rib is nearer what is regarded as the hinder end and is somewhat 
flattened in section. Above the figure is a section taken at the anterior end of the bone. Another 
peripheral (fig. 182) is about 87 mm. long, 82 mm. wide, 18 mm. thick at one end, 14 mm. at 
the other. In the visceral face is a pit for the end of a rib. Each diameter of the pit at its 
opening is 9 mm. The upper face is quite concave from the acute free border to the costal 
border. Near the figure is a section (182(7) taken at the thicker end of this peripheral, which 
represents the diameter and depth of the rib-pit. Another peripheral, probably a ninth or 
tenth, has the costal border broken away. The rib-pit is flattened. Figure 183 is a section of 
this bone. Its greatest thickness is 24 mm. Fig. 184 is a section taken along the transverse 
sulcus of a fragment representing about one-half of a peripheral. The upper and lower faces 



150 FOSSIL TURTLES OK NORTH AMERICA. 

measure 48 mm. each, while the concave visceral face is 22 mm. wide. The mouth of the pit 
is circular. 

Cope referred to this species a specimen which now has the number 2351 of the American 
Museum and which is regarded here as belonging to the species since described by Wieland 
as Propleura horealis, here as Osteopygis borealts. If all of the peripherals described by Leidy 
belong to the same species this can not be the same as Cope's species; for the peripheral here 
represented by fig. 181 is too long and narrow. Furthermore, the peripheral with the missing 
costal border is too thick. In the doubt, therefore, it seems best to regard Leidy's materials 
and Cope's as belonging to distinct species, making the elongated peripheral of Leidy's spec- 
imens the type of his species and leaving it to future discoveries to determine whether or 
not any of Leidy's materials are co-specific with Cope's specimen. 

Genus CATAPLEURA Cope. 

A genus not well known. Nuchal bone little broader than the anterior peripherals. 
Nuchal and first and second peripherals suturally joined to the first costal bone. The other 
peripherals to the eleventh probably not suturally connected with the disk of the carapace. No 
pit in the second peripheral for the hyoplastron. A pit in the eleventh peripheral for the rib of 
eight costal. Plastron probably resembling that of Osteopygis, but not extending so far along 
the peripherals. 

Type : Catapleura repanda Cope. 

This genus differs from Lytoloma in having the two anterior peripherals solidly joined to 
the first costal. It differs from Osteopygis in the much narrower nuchal bone and in having 
no pit in the second peripheral for the process of the hyoplastron. From both Lytoloma and 
Osteopygis it differs in the much thicker posterior peripherals. 

The genus was establisht by Cope in 1870 (Ext. Batrach., Reptilia, Aves N. A., p. 
143). On page 235 of the work cited Cope exprest himself in doubt whether there were 
nine or ten costal plates present. In 1884 (Vert. Tert. Form. West., p. 112) doubt is exprest 
whether there were 9 costals. There can now be no doubt that this genus, like Osteopygis 
and the great majority of turtles, had only 8 pairs of costals. 

Catapleura repanda Cope. 

Figs. 185-188. 

Osteopygis repandus, CoPE, Proc. Acad. Nat. Sci. Phila. 1868, p. 147 (notn. nud.). — Hay, Bibliog. and 

Cat. Foss., Vert. N. A., 1902, p. 441. 
Propleura repanda. Cope, Cook's Gaol. New Jersey, 1868 (1869), p. 7^5 (nom. nud.). 
Catapleura repanda. Cope, Ext. Batrach., Reptilia, Aves N. A., 1869, p. 143, plate vii, fig. 2; Vert. Cret. 

Form. West, 1875, p. 259. 

The present species is based on very meager materials and none additional has been 
discovered since the first description of the species. The type is now in the American Museum 
of Natural History and consists of a part of the nuchal, the succeeding three peripherals and a 
part of the fourth of the right side, the first of the left side, and four other peripherals, one 
nearly complete costal and parts of others, and a portion of a femur. The catalog number is 
2353. These bones were obtained from the upper bed of Cretaceous greensand at Barnesboro, 
Gloucester County, New Jersey. 

The nuchal bone (fig. 185) is remarkable for its narrowness fore and aft, being only 47 mm. 
The widths of the first and second peripherals are respectively 43 mm. and 44 mm. The 
free border of the nuchal is somewhat obtuse and the thickness soon becomes 10 mm., at 
the end of the bone. The posterior border articulated suturally with the first costal. The 
posterior sutural edge is oblique to the surfaces of the bone and the nuchal slightly overlapt the 
first costal. The thickness of this border is 8.5 mm. The posterior border of the nuchal was 
much wider from side to side than the anterior border. On the end of the nuchal, nearer the 
anterior border, there is a notch which receives a process of the first peripheral (fig. 185). 
The latter measures 50 mm. along the anterior border, 17 mm. along the posterior. Its free 
border is more obtuse than that of the nuchal. The second peripheral (fig. 185) extends 53 
mm. along the free border. It is 13 mm. thick near the free border, 7 mm. thick at the hinder 



THALASSEMYDID^. 



151 



border. The hinder border both of this bone and'of the first peripheral is oblique and overlapt 
the first costal, as did the nuchal. The hinder half of the upper border of the second peripheral 
is broken away and we can not tell how much of it was sutured to the costal. There is no pit 
in the second for the anterior outer angle of the hyoplastron, and it is not probable that the 
latter bone extended so far forward. 

The third peripheral is 60 mm. long on the thickened and obtuse free border. On the inner 
face is a deep pit, directed backward, for the rib-end of the first costal. Below this, in the pro- 
jecting edge is a notch, possibly for a digitation of the hyoplastron. Of the fourth peripheral 
there is present only a portion. Its lower face is 26 mm. wide, and this makes an angle of ninety 
degrees with the upper face, the angle where they meet being rounded ofl^. The upper borders 
of the third and the fourth peripherals are broken away. Cope figured what he regarded as the 
sixth peripheral, and there is a fragment of a peripheral, which he has markt as the sixth; 
but it is impossible now to to say that the bone present is the one figured. The bone has one 
face, apparently the upper, 44 mm. wide. Another face, somewhat concave, is separated from 





¥iGS. l^^-lS^.—Catapleurarepandii. Portions of shell of type. Xj. 

185. Nuchal, and first and second peripherals, nu.p, nuchal bone; per. l, per. 
2, first and second peripherals. 

186. Portions of the eighth and ninth peripherals. Free border toward the right. 

187. Section across ninth peripheral. 188. Third or fifth costal. 

this by a subacute free border. Cope has figured what he regarded as the eighth and part of the 
ninth peripherals. In reality, there is only a small portion of the eighth and about two-thirds 
of the ninth (fig. i86). Evidently these belong to the right side, since the intermarginal sulcus 
crosses in front of the rib-pit. The latter is in the hinder half of each bone. The upper border 
of'the upper face of both these bones is missing, but that part of the face of the ninth which 
remains is 47 mm. wide and is slightly concave. The lower face, also slightly concave, is 46 
mm. wide. The inner face has been about 25 mm. wide. Fig. 187 is a section of the ninth 
along the intermarginal sulcus. The outer free border of the bone is acute and has projected 
slightly at the end of the intermarginal sulcus, making the free border somewhat repand. 

On the free border and between the two bones here described is a long notch which, during 
the life of the animal, inclosed a distinct ossicle. This reminds us of similarly disposed ossicles 
described by Wieland as occurring in his Lytolonia angusta (L. unelandi), and which he was 
inclined to regard as a part of a disappearing primitive osteo-dermal armor of turtles. From the 
manner of growth of the horny scutes one would rather expect to find such bones, if a part ot 
the ancient armor, at the ends of the intermarginal sulci. 



152 FOSSIL TURTLES OF NORTH AMERICA. 

There is present a part of a peripheral which Cope has labeled as the tenth. The upper 
borders of both the upper and lower faces are missing, but these faces are yet 58 mm. wide. At 
its upper, or proximal, border, the bone is 18 mm. thick. The hinder half of the bone is lost 
but enough apparently remains to show a part of the rib-pit, had it been present in the bone. 
Since in C. ponderosa the eighth costal sent its rib-end into the eleventh peripheral, it is prob- 
able that there was no pit in the tenth. If the bones regarded by Cope as the eighth, ninth 
and tenth are really such they differ greatly from the corresponding bones of Osteopygis, 
being, relatively to their length and height, much thicker. 

The costals are extremely interesting, but they are not well understood. There is one which 
is nearly complete, quite certainly either the third or the fifth. It has a width of about 50 mm. 
(fig. 188). The curvature shows that the carapace was considerably archt from side to side. 
Cope regarded this costal as that of the right side, but there are reasons for believing that it 
belongs to the left. One sutural border is thicker and has the suture oblique to the surface of 
the bone in such a way that it must have been overlapt by the contiguous bone. We have 
seen that the hinder border of the nuchal and the first two peripherals overlapt the first costal. 
It seems improbable that from having the anterior border overlapt in the first costal a change 
would be made, about the middle of the shell, to having the posterior border overlapt. The 
present costal can not, however, be the first, for the proximal end of its fellow bone is present 
and does not accurately fit to the nuchal and first peripheral. It can not be the second, for it is 
not traverst by a sulcus separating two costal scutes. It seems probable that it is the left 
third. The posterior sutural edge is at right angles with the surface and hence it did not overlap 
the succeeding bone. The thickness, too, is reduced to 5 mm. The upper surface of the costals 
is smooth. On the one described there are parts of 2 vertebral scutes, probably the second and 
the third. On the supposed posterior border of the bone the costo-vertebral sulcus is 25 mm. 
from the neural border. The surfaces of the peripherals are markt by zigzag vascular grooves. 

On the under side of the costal is seen a large rib-head and stout ridge proceeding from it to 
the distal end. At the proximal end this ridge lies a little nearer to the supposed anterior border 
and on its way to the distal end it gets closer to this border, being only 3 mm. away from it 
finally. In his description Cope states this ridge lies near the posterior border. In front, that 
is on the side next the beveled border of the costal, there is a rough groove, as if a rudimentary 
first rib had been applied against the ridge. The meaning of the groove is unknown. It is 
found in three of the costals represented. 

Not enough of the femur is present to furnish definite information regarding its structure. 
The head is missing. The shaft has a diameter of 11 mm. 

What is determinable regarding the vertebral scutes has been stated above. On the 
nuchal and the anterior peripherals the marginal scutes rise only a moderate distance above the 
free border of the shell. On the median and hinder peripherals the costo-marginal sulci appear 
to have followed the unossified space between the costal and peripheral bones. The nuchal 
bone does not reach the midline, and hence we can not determine exactly what was its width 
nor that of the nuchal and first vertebral scutes. The boundary between the nuchal scute and 
the first marginal is believed to be where shown in fig. 185. The first vertebral scute lacks a 
considerable space of reaching the outer ends of the nuchal bone, and was, hence, evidently 
narrow. The first marginal rises about 28 mm. above the border of the carapace; the second 
about 18 mm. 

Catapleura ponderosa Cope. 

Figs. 189, 190. 

Catapleura ponderosa, CoPE, Proc. Amer. Philos. See, XII, 1 87 1 , p. 46 ; Vert. Cret. Form. West, 1 875, p. 259. 
Osteopygis ponderosa, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 

The present species is based on materials even less satisfactory than is C. repanda. They 
consist of portions of the eleventh peripheral and the pygal, portions of about 6 costals, a 
part of a supposed hypoplastron, a scapular arch, a considerable part of a humerus, a part of 
a femur and a part of a lower jaw. 

The type is now in the American Museum of Natural History and has the number 1475. 
These bones were obtained by Cope from the uppermost bed of Cretaceous greensand, at 
Hornerstown, New Jersey. 



THALASSEMYDID.i;. 



153 



The pygal bone (figs. 189, 190) had a width of about 80 mm. along the free border. Some 
of the upper border has crumbled away, but the height of the bone was close to 65 mm. Its 
thickness a short distance below the upper border is 19 mm. The upper surface is concave fore 
and aft; convex from side to side. On the lower side the directions of these forms of surface 
are reverst. The free border is acute. The upper border was probably suturally articulated 
with the suprapygal. On neither the upper nor the lower side of this bone is there any trace 
of a sulcus. 

Of the eleventh peripheral Cope had no more than is now present, the hinder half, articu- 
lated with the pygal. It is concave from the free edge to the upper border on the upper surface, 
rather strongly convex on the lower surface. In the upper border there remains a portion of 
the deep pit forthe rib-head of the eighth costal. The greatest thickness of the bone is 19mm. 
While a considerable part of the free border is broken away, that remaining seems to indicate 
that this border was emarginate, as was stated by Cope. No sulcus appears on this bone. 

Two of the costals represented are evidently those of the same pair. Cope thought they 
were those of the second pair. The proximal end was 82 mm. wide. One of the sutural 
borders is 1 1 mm. thick, and the suture is oblique to the surfaces of the bone. It was evidently 
overlapt by the bone to which it was articulated. The opposite border is only 5 mm. thick. 
Under C. repanda reasons have been given for regarding the border bearing the oblique suture 
as the anterior one; and the costals of the two species are so similar that the same rule applies 
here. As in C. repanda, the rib-head is strongly developt, as well as the rib in its course along 





Figs. 189 and icp.—Catapleura ponderosa. Portions of type. X§. 
189. Pygal and eleventh peripheral. 190. Section along midline of pygal. 

the under side of the costal. As in C. repanda, this rib gets nearer and nearer the thickened 
side of the costal on its way toward the distal end. There is also a rough groove near the prox- 
imal end of the front of the ridge; but it is not so conspicuous as in the other species. More- 
over, it is seen only on the two costals supposed to belong to the second pair. 

On none of the costals or peripherals are there observed any remains of sulci, to mark the 
limits of the horny scutes. The costals are markt by very distinct branching vascular grooves. 

There is present a fragment of a plastral bone, which was interpreted by Cope as the 
hinder part of the left hypoplastron. The writer finds it impossible to identify the bone satis- 
factorily. One border is obtuse and 14 mm. thick. The opposite border is thin and irregular 

Only the proximal half of the right humerus is present. The long axis of the head 
measures 35 mm., the shorter 2+ mm. The radial process is missing, but it continued to the 
head of the bone. The ulnar process lacks much of rising to the level of the head, and the ridge 
descending from it runs well down on the shaft. The planes of the radial and ulnar processes 
make with each other an angle of more than 90°. The shaft of the bone is comprest having 
a diameter of 15 mm. in the perpendicular plane ; of 1 1 mm. in the horizontal. It is therefore 
comprest in a manner directly opposite to that of the C/!(?/on/ic/a-. ... 

The femur is that of the right side and lacks the distal end. The portion remaming is 93 
mm. long; and the whole bone must have been about 120 mm. long. As in the nriore primitive 
turtles, the head and the processes resemble those of the humerus. The head has diameters 
respectively of 23 mm. and 30 mm. 



154 



FOSSIL TURTLES OF NORTH AMERICA. 



The fibular process rises only to the lower level of the head. The tibial process is broken 
off. The planes of the two made with each other an angle of more than 90°, and there is a 
broad fossa between them, open below. The ridge from the tibial process runs far down on 
the shaft. The least diameter of the latter is 12 mm. 

The present species appears to differ from C. repanda in having no traces of sulci between 
the epidermal scutes, in having the ridge formed from the rib on the under side of the costal 
more strongly developt and more angular, and apparently in having the hinder peripherals 
more recurved toward their free margins. To judge from the types, C. ponderosn was con- 
siderably the larger species. 

In his description of this species Cope mentions a portion of the mandible which had 
accompanied the other bones. This bone is now at hand. It consists of the right dentary. The 
tip of the dentary and the hinder portion of the cutting-border are missing. The break 
between two dentaries appears to have followed the midline. The length of the symphysis 
was close to 36 mm. and its hinder end extended back to a line joining the mental foramina. 
The latter are small. From the symphysis the upper surface of the dentary descends slightly 
outward, then rises considerably to the cutting-border. The lower side of the dentary is 
flat for a considerable distance on each side of the midline, then rises in a strong curve to 
the cutting-edge. The thickness at the hinder end of the symphysis is 1 1 mm. The jaw is 
strongly grooved behind. This dentary resembles that described under O. chelydrinus; but, 
having the same width, the latter is thicker and heavier. 

Genus LYTOLOMA Cope. 

Lower jaw with broad, flat crushing-surface and long symphysis; the tip not beaked. 

Carapace resembling that of Caretta caretta but less pointed behind. None of the anterior 
peripherals suturally articulated with the costal plates, rib-pits of most of the peripherals in 
the hinder half of these bones. The eleventh peripheral with pit for rib of eighth costal. 
Plastron not well known, but believed to have a narrower connection with the carapace than 
in Osteopygis. Limbs not well known, the humerus and femur supposed to have about equal 
development, with tendencies toward the structure of the same parts in Cheloniidae. 

The type of this genus is Lytoloma angusta Cope. This is represented by some peripherals 
and a lower jaw, all supposed to belong to the same individual. Dr. Wieland has described and 
figured a considerable portion of a carapace which he referred provisionally to L. angusta, but 
which is here placed with doubts under L. wieland t. 

A considerable number of species from the Eocene of England and Belgium have been 
arranged under this genus, after having been assigned variously to Chelone, Euclastes, Puppi- 
gerus, Glossochelys, Pachyrhynchus, Thalassochelys, and Erquelinnesia. For the discussion of 
the subject the reader is referred to the original papers. These are cited by Mr. Richard 
Lydekker in his Catalogue of Fossil Reptilia, part iii, page 51. 

It is evident, however, that few, if any, of these species really belong to Lytoloma. Owen 's 
Chelone crassicostata, the palatal view of which is figured by Lydekker (Proc. Zool. Soc. Lond., 
1889, pi. vi), under the name of Lytoloma crassicostatum, has the choanae pushed backward to 
the hinder third of the skull, and the palatine bones meet for a considerable distance behind 
the vomer. In the article accompanying the figure just cited Mr. Lydekker informs us that 
Dollo's species originally described under the name of Pachyrhynchus gosselett is identical 
with Owen's Chelone crassicostata. For the genus represented by this species it appears that 
Dollo's name Erquelinnesia will have to be employed. 

The skull of Owen's Chelone planimentum resembles in general that of his C. crassicostata, 
but its palate appears not to have been described. Nevertheless, the carapace presents several 
peculiarities. The neurals have the antero-lateral and the postero-lateral sides equal, the ribs 
present themselves on the under side of the costals as prominent, narrow, and angular ridges, 
and the peripherals are much more reduced than in C. crassicostata. It seems probable that 
we have here a distinct genus, and for this Seeley's name Glossochelys will be available. 

Dr. W. B. Clark has publisht (Johns Hopkins Univ. Circ. xv, 1895, No. 4; Bull. U.S.Geol. 
Surv., No. 141, 1896, p. 59) a mention of some fragments of a large carapace found in the 
Aquia formation in Maryland, which he supposed might belong to Cope's Euclastes. Case 



THAI.ASSEMYDIDiE. 



155 



(Geol. Surv. Maryland, Eocene, 1901, p. 97. pi. x, fig. 7) has repeated Dr. Clark's words and 
figured one fragment. The materials are generically indeterminable. 

Lytoloma angusta Cope. 

Plate 28, figs. 5, 6; text-figs. 191, 192. 

Chelone sopita (in part), Leidy, Smithson. Contrib. to Knowledge, xiv, 1865, p. 105, plate xix, fig. 5. 
Lytoloma angusta. Cope, Amer. Naturalist, lll, 1869, p. 105 (nom. nud.); Ext. Batrach., Reptilia, Aves 

N. A., 1869, p. 145, plate xi, figs. I, lb; Vert. Cret. Form. West, 1875, p. 257. — Hay, Bibliog. and 

Cat. Foss. Vert. N. A., 1902, p. 442. 

Cope's first mention of this species was in the American Naturalist, as quoted above, but 
this mention was made only incidentally and what was said is not sufficient to distinguish 
either the species or the genus from various other turtles. When he came to describe and figure 
the species Cope stated that his materials consisted of three peripheral bones, a fragment of a 
costal, and a lower jaw. He says that the costals and marginals were found at the same time and 
place as the jaw and probably belong to it. It seems that he regarded the peripherals as the 
type of the species, and since he figures only one of these, this especially must be taken as the 
type. That he so regarded the peripherals is evident from the fact that 
from peripherals alone of this species and L. jeanesi he drew all his generic 
characters. Further proof is afforded by the specimen of the jaw itself, 
which bears, in Cope's writing, the label '"f" Lytoloma angusta Cope, Bir- 
mingham, N. J." In case he had lookt upon the jaw as the type he could 
hardly have questioned its belonging to the species. It is wholly prob- 
able that at least the figured peripheral and the costal belong with the 
jaw; and until it has been shown that they do not, all may pass as types. 
These specimens were obtained in the upper greensand beds of the Creta- 
ceous, at Birmingham,nearPemberton, New Jersey. Inasmuch as the jaw 
is labeled by Cope as coming from Birmingham, it is probable that the 
specimens were obtained from some marl-pit between the two towns. 
They are now in the American Museum of Natural History and bear the 
number 1133. 

The figured peripheral (plate 28, fig. 6) is said by Cope to belong to 
the left side, but on the bone itself he has written "5 R," from which 
it appears that he regarded it as the fifth of the right side, and such it 
seems to be. It has a length, along the acute free margin, of 67 mm. A 
section of the bone is triangular, and therefore it shows three faces (fig. 
191). The visceral face is 22 mm. wide, somewhat concave, and contains 
in the hinder half of the bone a deep conical pit for the rib-end of the 
third costal. The upper face is slightly concave at right angles with the 
free border, 22 mm. wide at the anterior end, 29 mm. at the posterior. 

191. Section through fifth yj^g inferior face is slightly convex and 32 mm. wide at each end. 

shown 'bTinte^r- Another peripheral (fig. 192) is markt by Cope " .?2 R." It has a 

rupted line. length of 70 mm., a thickness at the visceral face of 16 mm. at one end 

192. Supposed second ^^^ j^ ^^ ^^ j|^g Other. The upper and lower faces are somewhat con- 

ng t perip era . ^^^ ^^ ^^^ ^^^^ border there is a broad emargination. At the bottom 
of this emargination the bone is 28 mm. wide. At one sutural end the width is 34 mm. There 
is no rib-pit in the visceral face. The peripheral, supposed by Cope to be the fourth, is not 
now with the other bones. 

The fragment of costal has a width of 47 mm. near the sutural border for the neural. At 
the middle of the width the thickness is 10 mm.; at the sutural border it is about 4 mm. As 
stated by Cope, there is present the sulcus bounding one of the vertebral scutes. From a 
comparison with the figure publisht by Wieland, and here reproduced (fig. 196), this costal is 
believed to be the sixth of the right side. The outer angle of the vertebral scute is placed near 
the hinder sutural border of the bones, at a distance of 50 mm. from the neural. 

The lower jaw (plate 28, fig. 5) is of the greatest interest. It is considerably eroded and 
does not lend itself well to illustration. It is remarkable for the great length of the symphysis, 




Figs. 191 and 192. — 
Lytoloma angusta. 
Peripherals of 
type. Xf. 



156 FOSSIL TURTLES OF NORTH AMERICA. 

52 mm., and for the flatness of the triturating surfaces. An unimportant part of the tip of the 
jaw is broken off. There was certainly no upturned beak, such as there must have been in 
Rhetechelys platyops (Cope); nor was there a cutting-edge that rose much above the triturating 
surface. The lower surface of the jaw is likewise very flat, rising abruptly toward the free 
borders. The thickness at the hinder end of the symphysis is 18 mm.; at a distance of 25 mm. 
behind the tip the thickness is 16 mm. The coronoid process rises 40 mm. above the bottom 
of the ramus. The rami are thoroly co-ossified. There are no other bones of the jaw 
present except the right coronoid, which is crowded to the inside of the coronoid process of the 
dentary. 

At the tip of the jaw the borders of the dentaries diverge at an angle slightly greater than a 
right angle. At the fronts of the fossae for the masseter muscles the width is 91 mm.; at the 
hinder end of the dentaries it is 1 10 mm. The fossae just mentioned are large and deep. That 
part of each on the dentary is 40 mm. long and 26 mm. high. At the front of each fossa is 
a mental foramen. A line passing from one of these to the other falls 12 mm. in front of the 
hinder end of the symphysis. 

The fragmentary skull materials described by Wieland provisionally under the name of 
L. angusta (Amer. Jour. Sci.,xviii, 1904, p. 184, 185, figs. I, 2) are here made the types of a 
new species. The carapace which that author has also referred to /.. angusta (op. cit., p. 
187, pis. vi-viii) doubtfully belongs to it. In case the peripheral regarded by Cope as the 
second really belongs with the type, the carapace described by Wieland certainly does not 
belong to the species to which he has assigned it, for that peripheral in the type has the border 
emarginate. Furthermore, the fifth peripheral of L. angusta does not resemble closely any 
of those of the carapace described by Wieland. It resembles most nearly the fifth of Wie- 
land's specimen, but differs in relative length and width; apparently also in the position of 
the pit for the rib. Only future discoveries can decide this point. 

The bones figured by Leidy (as cited in the synonymy) under the name of Chelone sopita 
have been referred by Cope to Lytoloma angusta. They appear not to agree with any species 
of Osteopygts in that they are much longer than wide, have the sulci crossing the middle of 
the length and have the pits well toward the rear end of the bone. 

L.ytoloina jeanesi Cope. 

Figs. 193-195. 

Prophura jeanesii, CoPE, Cook's Geol. of New Jersey, 1868 (1869), p. 735 (nom. nud.). 
Lytoloma jeanesii. Cope, Ext. Batrach., Reptilia, Aves N. A., 1869, p. 145; \tn. Cret. Form. West, 
1875, p. 257. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 452. 

Of this species Cope studied what he regarded as portions of 2 individuals. Of the first, 
discovered in the upper bed of Cretaceous greensand, near Barnesboro, Gloucester County, 
New Jersey, there were secured only the nuchal bone and the first peripheral. Cope appears 
to have lookt upon this lot as the type of the species. Where these bones are now is not 
known. The second individual was obtained in the same bed of greensand, at Hornersville, 
New Jersey. This specimen, or most of it, is now in the American Museum, where it has the 
number 1473. 

The nuchal bone which belonged to the first-named individual was described by Cope as 
resembling an ordinary peripheral, differing entirely from the nuchal of Chelydra and Chelone. 
.The anterior border appears to have been obtuse. Its length, from side to side, is not given; 
the width is stated to have been 16.5 lines (about 34 mm.). The nuchal scute which it bore is 
said to have been about 18 mm. wide. The bone is described as having joined the first 
.peripheral by a coarse gomphosis, the process coming from the first peripheral. There was 
also a sutural border for union with the first neural; but we are not told whether or not the 
nuchal articulated with the first costals. 

The first peripheral is described as having a free inner border, a condition showing that it 
did not articulate with the first costal. Its suture with the nuchal was straight; that with the 
second peripheral had the entering angle seen in Osteopygis sopitus, etc. The width of the first 
peripheral is given as 15.5 lines, about 32 mm. This width was three-fifths of the length, 
therefore about 53 mm. 



thai.assemydiDj*:. 



»57 



Of the second individual examined by Cope the first peripheral is at hand (fig. 193). It 
has an obtuse free outer and an acute free inner margin. The thickness near the proximal 
end and the outer border is 12 mm. At the hinder end (fig. 194) the thickness is somewhat 
less. On the distal half of the bone and near the free margin, or rather, forming the free 
margin, is a low sharp ridge, at which the upper and the lower surfaces meet. The suture with 
the nuchal is oblique, running from the inner border forward and toward the midline, then 
forward and outward, then again forward and toward the midline. The end of the bone was 
somewhat overlapt by the nuchal. The length along the free outer border is about 65 mm.; 
along the free inner border, about 40 mm.; from one extremity to the other, 80 mm. The 
greatest width is 35 mm.; that near the hinder end is 27 mm. 

The peripheral regarded by Cope as the sixth (fig. 195) has a length of about 100 mm. 
A part of the free border is broken away. The bone is triangular in section, presenting thus 
three faces. The inner or visceral face is quite concave the whole length and has in the 
hinder half a deep conical pit for the end of a rib. The bone is about 30 mm. wide. The lower 
face is slightly concave and is 30 mm. wide. The upper face has a width of from 35 mm. to 
38 mm. and it is nearly plane. According to the present interpretation, the bone belongs to 
the right side. All of the free borders are acute, especially the upper inner, and in none of 
them is there any emargination. 




Figs. 193-195. — Lytoloma jeanesi. Peripherals. X|. No. 14.73 A. M. N. H. 

193. Right first peripheral. 

194. Section near distal end of first peripheral. 

195. Section of sixth .^ peripheral. Pit shown by interrupted line. 

Accompanying the bones above described is a fragment of a costal which agrees in its 
dimensions with the one mentioned by Cope. Its width is 90 mm., while the thickness 
thru the middle of the width is II mm. Cope states that the costals showed no sculpture. 
However, the present costal has its surface broken by numerous pits of varying form and size, 
resembling thus closely the costals of Osteopygis erosus. It is probable that the bone belongs 
elsewhere. 

The peripheral described above as probably the sixth differs so much from the fifth of 
L. angusta that a distinct species is clearly indicated. The ratios of width to length in the 
two bones are very different. The width of the peripheral of L. angusta is contained in the 
length about two and a third times; while in that of L. jeanesi the width is contained in the 
length three and a third times. The results are equally decisive in case both peripherals 
should happen to be fifths or sixths. It is wholly probable that neither of them can belong 
farther backward in the series. 

The various measurements of this bone show that the carapace described by Wieland can 

not belong to L. jeanesi. 

Lytoloma wielandi sp. nov. 

Plate zS, figs. 7, 8; plate 29, fig. i; teit-figs. 196, 197. 

Lytoloma angusta?, Wieland, Amer. Jour. Sci. (4), xviii, 1904, p. 183, plates vi-viii, text-figs. 1-3; 
Ibid., XX, 1905, p. 333, fig. 5. 

Dr. George R. Wieland has, with exprest doubts, referred some lower jaws, the front of a 
skull, and a carapace of a Lytoloma to L. angusta. His specimens are in the Yale University 
collection. The skull bones were secured by Professor O. C. Marsh from the upper Cretaceous 
greensand bed at Hornerstown, New Jersey. The carapace came from Barnesboro. It seems 
evident that these remains do not belong to the species to which they have been assigned, 
and they are here made the types of a new species, named in honor of Dr. Wieland. 



158 FOSSIL TURTLES OF NORTH AMERICA. 

In case it shall hereafter be discovered that more than a single species is represented by 
these bones, the lower jaw figured by Wieland shall be regarded as the type of L. wielandi. 

That this lower jaw is not identical specifically with that regarded as belonging to the 
type of L. angusta appears from the following considerations: 

(1) The angle subtended by the cutting-borders of the jaw of L. angusta forms at least a 
right angle; in L. wielandi this angle is 80 degrees. 

(2) In L. angusta the lateral outlines of the jaw continue outward and backward in nearly 
straight lines to the mental foramina; in L. wielandi the borders are deflected more nearly 
backward at a considerable distance in front of these foramina. 

(3) In L. angusta a line drawn from one foramen to the other falls 12 mm. in front of the 
hinder end of the symphysis; in L. wielandi it falls at the hinder end of the symphysis. 

(4) In L. angusta the descent from the summit of the coronoid is much more abrupt than in 
the other species considered. In the former species the height of the coronoid process is 77 
per cent, of the length of the symphysis; in the new species, only 60 per cent. 

(5) The tip of the jaw of L. wielandi appears to have been more upturned, more acute, 
and in every way more beak-like than in L. angusta. 

DiflFerences so great as indicated above in two jaws whose symphyses are respectively 52 
mm. and 42 mm. can hardly be attributed to differences in age or sex. At least, so great 
differences do not appear in a number of jaws of the loggerhead turtle, to which the jaws of 
Lytoloma have great resemblances. In a huge skull of the loggerhead, the length of which 
from snout to occipital condyle is 230 mm., the line joining the mental foramina falls at the 
hinder end of the symphysis, while it falls only 12 mm. behind the symphysis in a young 
specimen whose skull is only 130 mm. long. As to the lateral outlines of jaws, the elevation of 
the coronoids, and the form of the tip, there is not much difference among specimens of middle 
and large sizes. The angle subtended by the outlines of the anterior portions of the lower 
jaws of Caretta may, however, vary as much as in the case of L. angusta and L. wielandi. 

The width of the jaw forming the type of L. wielandi, taken at the mental foramina, is 
66 mm.; taken at the hinder ends of the dentaries, 75 mm. The length of the symphysis is 
42 mm. The greatest thickness at the symphysis is 1 1 mm. 

The front of the skull figured by Wieland agrees in size and in the angle made by the 
borders of the upper jaws with the lower jaw just described. A comparison made with the 
jaw of the loggerhead indicates that the skull of which it formed a part had a length of about 
156 mm. Seen from above or below, it resembles considerably the same part in the log- 
gerhead. Seen from the side, the tip of the snout is much more deprest than in the loggerhead, 
a condition due probably to the little-developt cutting-edge of Lytoloma. Plate 28, fig. 7, rep- 
resents Wieland's type skull seen from above; plate 28, fig. 8, as seen from below; and plate 
29, fig. I, as seen from behind. These figures are reproduced from drawings made for Dr. 
Baur in 1888. 

The orbit was large. The prefrontals joined along the midline for a distance of at least 
12 mm. and to a line crossing the skull considerably behind the fronts of the orbits. In Rhe- 
techelys platyops (Cope) the prefrontals were parted by the frontals to a line considerably in 
front of the orbits. 

The external nasal opening has its transverse and its longitudinal dimensions each 20 mm. 
The snout as seen from above is not acuminate, as it was in Rhetechelys platyops. 

The vomer appears, as in Rhetechelys platyops, to have wholly separated the horizontal 
plates of the palatines. It has a length of 33 mm. and a width of 20 mm. The width of the 
perpendicular plate of the vomer, between the narial passages, is 1 1 mm. The choanae are 
thrown well backward, but it is doubtful whether they were pushed backward as far as they 
were in R. platyops, to a line joining the hinder borders of the orbits. 

There is no certainty that the carapace described by Dr. Wieland belongs to the present 
species, and it is so referred only because it seems to belong neither to L. angusta nor L. 
jeanesi. 

This carapace (fig. 196) was received by Prof. O. C. Marsh, May I, 1869, it having been 
sent to him from the upper greensand bed of the Cretaceous, near Barnesboro, New Jersey. 

The estimated length of the carapace is 580 mm.; the greatest breadth, 530 mm. In 
general, it resembles the carapace of the loggerhead, but it is far less pointed behind, a con- 



THAI.ASSEMYDID^. 



159 



dition showing that the turtles of this genus had not yet become seafarers. At Dr. Wieland's 
disposal, belonging to this specimen, were wholes or parts of the third, fourth, fifth, and sixth 
neurals, wholes or parts of two suprapygals, wholes or parts of all the costals of the right side 
and of most of those of the left side, wholes or parts of all the peripherals of the left side behind 
the third and of most of those of the right side behind the third, and a portion of the pygal. 
The nuchal and the three anterior pairs of peripherals were missing. 

The neurals are hexagonal, with the broader end forward, and nearly as wide as long. 
The third is 44 mm. long and 44 mm. wide; the fifth 41 mm. long and 41 mm. wide; the sixth 
41 mm. long and 34 mm. wide. They are each 6 mm. or 7 mm. thick. The anterior suprapygal 




Figs. 196 and 197. — Lytoloma wielandi. Carapace and sections of peripherals of type. 

196. Carapace. X}. After W'iel and. f. p. i, c. p. 6, c. />. 8, first, siith, and eighth costals; c. j. i, c. s. 4, first and 

fourth costal scutes; /, lateral fontanels; m. 5. 5, m. 5. 9, m. j. 12, fifth, ninth, and twelfth marginal scutes; 
n. 3, n. 6, third and sixth neural bones; nu. p, nuchal bone; nu.i, nuchal scute; per. 2, per. 9, per. 
II, second, ninth, and eleventh peripheral bones; py, pygal; spy. 2, spy.'i, second and third suprapygal 
bones; v. j. 1 , r. i. 2, first and second vertebral scutes. 

197. Sections through middle of length of peripherals. Xj. The numeral on each indicates the position of the 

bone. The dotted line indicates the pit. py, section along middle of pygal. 

is 37 mm. long and 80 'mm. wide; the posterior, 60 mm. long and perhaps 80 mm. wide. The 
posterior articulated narrowly with the pygal. 

The costals varied in width from 50 mm. to 60 mm. It is evident that the first costals 
articulated with the nuchal at its outer extremities. Cope states that the nuchal of 
L. jeanesi articulated with the first neural, but he says nothing about the articulation with 
the first costals. The latter species possest a nuchal extremely narrow, little wider than 
the first peripheral, and therefore quite unlike that shown in Dr. Wieland's restoration. 

However, as Dr. Wieland's specimen lackt the nuchal and 
the anterior peripherals, we do not know their structure 
and connections. 

The eighth costal had its rib-end thrown back, so as 
to enter a pit in the eleventh peripheral, a feature common 
in the Cheloniidae. As in the Cheloniida;, too, there were 
extensive fontanels between the distal ends of the costals 
and the peripherals. 







Width. 


Peripheral. 


Length. 












Upper face. 


Inner face. 


4 


55 


»S 


24 


6 


71 


43 


ii 


8 


go 


56 


15 


10 


75 


60 


•3 



Vertebral. 


Length. 


Width. 


2 

3 

4 


loo 

no 
.14 


•45 

•35 
ISO 



l6o FOSSIL TURTLES OF NORTH AMERICA. 

The peripherals have each three faces, an inner or visceral, a superior, and an inferior. 
Each of them, from the fourth to the ninth inclusive, has a pit for the reception of the end of 
a rib. Fig. 197 from Wieland represents sections of these peripherals. It will be observed that 
they grow broader and thinner from the front of the carapace. The dotted line in each repre- 
sents the depth of the pit. The table, p. 159, gives the dimensions of some of the peripherals. 
Dr. Wieland has described certain ossicles intercalated between the peripherals along the 
free borders of his specimen. He suggests that these are a part of the disappearing osteo- 
dermal covering of primitive turtles. 

The carapace was covered with horny scutes, which have left distinct impressions of the 
sulci on the various bones. There were, so far as appears, 5 vertebral scutes, 4 pairs of costals, 
and probably 12 pairs of marginals and a nuchal. The vertebrals are strongly angulated 

laterally where the sulci running down between the costals are 
given off. The table herewith shows the dimensions of three 
vertebral scutes. 

How high on the costal bones the marginal scutes rose can 
not be determined. 

There were preserved with this carapace some fragments of 
the plastron, but not enough to permit a restoration of it. Wie- 
land regards the plastron as having been more reduced than it 
was in Osteopygis, but otherwise much like it. Small pits in the hinder half of the lower 
inner free margin of the fourth peripheral show that the hyoplastron extended forward only 
to it. There are no pits to show how far backward the hypoplastron extended. 

The reasons for regarding this carapace as distinct from that of L. angusta are presented 
under the latter species. 

Genus ERQUELINNESIA DoUo. 

Pachyrhynchus, DoLLO, Bull. Mus. roy. d'Hist. nat. Belgique, 4, 1886, p. 130 (preoccupied). 
Erquelinnesia, DoLLO, Geol. Magazine (3), iv, 1887, p. 393. 

Skull resembling that of Caretta caretta, but more elevated and descending more rapidly 
in front of the orbits. Palate flat, bounded by low cutting-edges, and extending backward to 
the hinder half of the roof of the mouth. Choanae in the hinder half of the roof of the mouth, 
their anterior boundary formed by the palatines, which have met behind the palatal plate of 
the vomer. Lower jaw not beakt. Shell resembling that of Caretta, but more rounded behind. 

Type: Erquelinnesia gosseleti Do\\o = Chelone crassicostata Owen. 

For the structure of the palate of this genus the reader is referred to Mr. R. Lydekker's 
figure of Lytoloma crassicostaium (Proc. Zool. Soc, London, 1889, plate vi). This figure 
shows that the choanae are placed in the posterior third of the cranium and that the palatal 
plates of the palatine bones meet each other in the midline behind the vomer and beneath the 
narial passages. In the article accompanying this plate Mr. Lydekker states that Dr. Dollo's 
Erquelinnesia gosseleti is identical specifically with Owen's Chelone crassicostata. For refer- 
ence to other views of the skull and to figures of the carapace of this species, and to the 
literature, the reader is referred to Lydekker's Catalogue of Fossil Reptiles, part iii, 1889, 
page 60. On page 26 of this work is presented a figure of the humerus of E. crassicostata. 
It is evident that the members of the genus had not yet developt a limb adapted for life on 
the open sea. 

The following species is assigned provisionally to Erquelinnesia on account of the great 
length of the symphysis of the lower jaw. This seems to indicate that the choanae were located 
far toward the rear of the skull, so far that the palatines must have met behind the vomer. It 
is probable that in Osteopygis the choanae were not removed so far toward the rear of the skull. 

Erquelinnesia molaria sp. nov. 
Figs. 198, 199. 

This species is based on a lower jaw which is found in the collection of the Academy of 
Natural Sciences of Philadelphia. It is labeled as being Lytoloma platyops, as having been 
presented by Rev. L. H. Lighthipe, and as having been secured at Birmingham, New Jersey. 
It has, therefore, been collected from the upper bed of the Cretaceous greensand. 



THALASSEMYDIDiS. 



l6l 



This jaw (figs. 198, 199) is remarkable for the great length of the symphysis, this length 
considerably exceeding that of Lytoloma angusta. The width of the jaw, at the mental fora- 
mina, is 88 mm.; at the hinder ends of the dentaries, 100 mm., dimensions almost exactly those 
of the jaw belonging with the type of L. angusta. The length of the symphysis is 65 mm., that 
of the jaw of L. angusta being 52 mm. In the latter species the hinder end of the symphysis 
falls 12 mm. behind the line joining the mental foramina; in E. molaria it falls 22 mm. behind 
that line. The triturating surface is flat to near the inconspicuous cutting-edges, to which 
it ascends. The lower surface of the jaw also is flat, ascending rather abruptly to the cutting- 
edges. Anteriorly the lower surface approaches gradually the upper surface at the sharp- 
edged tip of the jaw. The outline of this tip 
is truncated and about 20 mm. wide. The 
coronoid process rises about 33 mm. above the 
bottom of the ramus, and the descent from it 
toward the tip of the jaw is gradual. The 
masseter fossa is large. 

The greatest thickness of the triturating 
surface is near the hinder end of the symphysis. 
The angle between the borders of the jaw, in 
front, is considerably more than a right angle. 
This jaw can not be that of Rhetechelys 
platyops (Cope) for at least two reasons. The 
angle between the lateral borders is too great 
to fit the upper jaw oi R. platyops. The type 
of the latter species belonged to an individual 
about twice as large as the possessor of the jaw 
here described; and, if they belonged to the 
same species, the angle of the jaw of the type of 
R. platyops ought to be the larger. Again, in case 
the present jaw had belonged to R. platyops, 
the hinder end of the symphysis would have 
fallen a distance behind the choanae equal to the 
length of the palatal plate of the vomer. The 
results of this would have been that a large part 
of the triturating surface of the lower jaw would 
have had no surface to oppose it and it would 
have been applied against the choanae, thus interfering with breathing. 

From both Lytoloma angusta and L. wielandi this species differs in the greater length of 
the symphysis and in the smaller angle between the borders of the jaw. 

Genus RHETECHELYS nov. 

Skull broad and deprest. Temporal region widely rooft over. Triturating surface of upper 
jaw broad, involving the maxillae, the palatines, and the vomer. Choanae near the middle of 
the roof of the mou h; the palatines not meeting behind the vomer. A pit between the pre- 
maxills for the reception of the upturned beak of the lower jaw. Shell and limbs unknown. 

Type : Euclastes platyops Cope. 

This genus diflPers from the species of Lytoloma (to which genus it has been referred since 
the discovery that the name Euclastes is preoccupied) in having had the tip of the lower jaw 
furnisht with an upturned beak. The existence of this is inferred from the presence of a deep 
depression between the palatal plates of the premaxillae and an interruption of the bone. 
Similar conditions are found in the skull of Macrochelys. Osteopygts, Lytoloma, and Erquelin- 
nesla all have lower jaws with broad, flat triturating surfaces, but m none of them do we hnd 

any traces of a beak. ■ ■ 1 in 1 j 

The only known species of the genus was a large and powerful animal, whose skull equaled 
in size that of the largest specimens of the living loggerhead. 
II 




Figs. 198 and igg. — Erquelinnesta molaria. 
Lower jaw forming the type. X§. 

198. Upper view of jaw. 199. Side view of jaw. 



l62 FOSSIL TURTLES OF NORTH AMERICA. 

Dr. W. B. Clark has referred provisionally (Johns Hopkins Univ. Circ, xv, 1895, No. 4; 
Bull. U. S. Geol. Surv., 141, p. 59) some fragments of a large turtle to Euclastes. One of these 
fragments has been again mentioned and figured by Dr. Case in the Eocene volume of the 
Geological Survey of Maryland (p. 97, plate x, fig. 7). The fragment is not susceptible of 

generic determination. 

Rhetechelys platyops (Cope). 

Plate 29, figs. 2, 3. 

Euclastes platyops, CoPE, Proc. Acad. Nat. Sci. Phila. 1867, p. 41; Cook's Geo!. New Jersey, 1868 
(1869), p. 735; Amer. Naturalist, in, 1869, p. 89; Ext. Batrach., Reptilia, Aves N. A., 1869, p. 
149, plates vi, vii, fig. 9; Vert. Cret. Form. West, 1875, p. 259. 

Lytoloma platyops, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 442. — ^WlELAND, Amer. Jour. Sci. 
(4), xviii, 1904, p. 185. 

FPropleura sopita, CoPE, Ext. Batrach., Reptilia, Aves N. A., 1869, p. 140 (Harrisonville specimen). 

All that we know at present regarding this species is what is to be derived from the type 
skull. This is in the collection of the Academy of Natural Sciences at Philadelphia. It was 
found in a coarse granular limestone, at HurfFsville, Camden County, New Jersey. This 
deposit belongs to the Upper Cretaceous and was regarded by Cope as equivalent to the Fox 
Hills group. The species formed the type of Cope's genus Euclastes, a preoccupied name. 

The skull was a large one, the total length being estimated by Cope as 11 inches, about 
280 mm.; but this must have included the supraoccipital process. At any rate, the length was 
equal to that of the largest specimens of Caretta. The occipital condyle is missing, but the 
length from the premaxillae to this condyle must have been close to 200 mm., perhaps a little 
more. The width, a short distance behind the orbits, is 220 mm. From this widest part the 
aiteral outlines converge rapidly to the pointed snout. Beneath the orbit the outlines are 
slightly concave. The angle included between the borders of the maxillae is somewhat less 
than a right angle. The roof is broad and deprest, the frontal region being flat. The slope 
from the rear to the nasal opening is only slightly sinuous. There is no such sudden descent 
from the orbits to the premaxillae as we see in the species oi Glossochelys. The temporal region 
was broadly rooft over, as in Caretta, but extended backward still further. The various bones 
appear to have been disposed about as in the living genus mentioned. 

The orbits look outward, forward, and upward. The upward inclination exceeds that of 
Caretta. The greatest diameter of the orbit is 63 mm. The least interorbital width is about 
50 mm. The frontal bones are more produced forward than in Caretta, their suture measuring 
55 mm. They are excluded from the rim of the orbits by the union of the postfrontals with the 
prefrontals. The latter bones meet along the midline a distance of 12 mm. 

The nasal opening has a width of 30 mm. It looks forward and strongly upward. As in 
other Cryptodira, the prefrontals send downward on each side a column of bone to the vomer. 

The roof of the mouth resembles in general that oi Caretta, but there are important differ- 
ences. The cutting-edges of the maxillae are only feebly developt, descending but little below 
the level of the grinding surface. This surface is formed by the union of the palatal plates of 
the premaxillae, maxillae, vomer, and palatines. It extends backward a distance of nearly 
100 mm. from the premaxillae. It is somewhat concave on each side of the vomer and in the 
premaxillary region. In the roof of the mouth the maxillae are each 41 mm. wide; the palatines 
about 26 mm. The vomer is 50 mm. long and 28 mm. wide. 

The occipital condyle is missing, but the choanae fall within the anterior half of the length 
to the roof of the mouth. They are bounded laterally by the palatines and anteriorly by the 
vomer, the edge of this being 98 mm. behind the tip of the snout. They are thus quite different 
from those of the species of Erqueltnnesia. The palatal openings of the temporal fossae are 
broader than long. The borders of the pterygoids were strongly emarginated. 

Between the anterior ends of the premaxillae is a perforation supposed to be for the recep- 
tion of a hook on the lower jaw, as in Macrochelys. 

Professor Cope supposed that the whole length of the animal which possest this skull 
was a little over 6J feet; but it is not safe to estimate the size of a turtle from the size of the 
head. Nevertheless, it must have been a large and formidable brute. Probably it haunted 
the coasts of the Cretaceous seas, betaking itself at times to some distance from the shore. 



THALASSEMYDID^. 163 

Its food has been supposed to have been hard-shelled animals, such as moUusks, which were 
crusht between its mill-stone-Iike jaws. The possession of a hookt beak like that of the 
alligator-snapper suggests, however, that the animal may have been accustomed to the captur- 
ing of a more active prey, such perhaps as fishes. 

Cope, as cited in the synonymy above, referred certain bones obtained at Harrisonville, 
Salem County, New Jersey, to Propleura sopita. These consisted, as he says, of 2 peripheral 
bones, part of a costal, half a femur, and 2 phalanges. This lot is in the American Museum and 
is found to include three peripherals, a fragment of a costal, and the distal end of a femur. 
The foot bones are missing. The number is 2361. These bones quite certainly do not belong 
to Osteopygis. In all specimens known to belong to the latter genus the pit for the rib-end is 
placed at the middle of the length of the peripheral or not far behind it. Only in the tenth 
peripheral is it placed close to the hinder end of the peripheral. In the bones of the Harrison- 
ville specimen the pit is placed far backward. Since Rhctechelys platyops was found in the 
same limestone not many miles distant, the bones found at Harrisonville are referred provis- 
ionally to the species just named. 

One of the peripherals appears to be the left first. Its length is 85 mm.; its height 48 mm.; 
the thickness of the obtuse free border, 19 mm. in front. The articulation with the first costal 
was not strong and apparently only along the anterior end ot the bone. It is not certain that 
any part of the first vertebral scute descended on this peripheral. Another peripheral is prob- 
ably the left fifth. The anterior end is broken off, but the length must have been about 1 10 mm. 
From the hinder end to the intermarginal sulcus is 60 mm. The height of the upper face, at 
the sulcus, is 62 mm.; the lower face, 53 mm.; the inner face, 50 mm. The pit is in the hinder 
third of the bone. The upper face is slightly concave; the lower slightly convex; the inner 
concave. The remaining peripheral is probably the seventh. Cope regarded it as the eighth. 
Most of the outer border is broken away. The length is 95 mm.; the height, 79 mm.; the 
thickness of the costal border, 28 mm. in front, 24 mm. behind. The upper surface is some- 
what concave; the lower, convex; The circular rib-pit is almost wholly in the hinder third 
of the inner face. The piece of costal is 7 mm. thick at the sutural border. All these bones 
are smooth, but markt by vascular grooves. The width of the femur at the distal end is 45 
mm. The diameter of the shaft is 19 mm. The bone was considerably bent. 

FamUy TOXOCHELYID.«; Baur. 

Skull somewhat deprest. Temporal region extensively rooft. Quadrate notcht for the 
columella. Choan^ situated well forward; not underfloored by the palatines. Palatines 
extending forward to the vomers and forming the outer boundaries of the choanae. Carapace 
with eleven pairs of peripherals, in addition to the nuchal and pygal. Nuchal not furnisht with 
costiform processes. Epidermal shields present. Plastron loosely articulated with the carapace, 
not extending forward to the third peripheral and backward hardly to the eighth. Fore foot 
with at least 2 claws; the phalanges furnisht with condyles; the limb as a whole resembling 
that of the Trionychidae. 

Genera 2, Toxochelys and Porthochelys. With these may be included provisionally the 
insufficiently known genus Cynocercus. 

The writer excludes the members of this family from the Cheloniidx especially because the 
fore limb had not yet become develop! into a flipper like that of the modern sea-turtles. The 
humerus offers scarcely an approach to that of the sea-turtles. Nor was the hinder limb 
nearly so much reduced as in the latter. The limbs were probably greatly like those of the 
Trionychidse. That the anterior limbs were not habitually employed in swimming appears to be 
shown by the fact that the shell was not excavated over these limbs as it is in the Chelonndae. 

Genus TOXOCHELYS Cope. 

Skull longer than broad. No nasal bones. Carapace with large lateral fontanels. None 
of the peripherals in contact with the disk of the carapace. Midline with prominent carma 
rising at intervals into tubercles, some of which are distinct bones. Tail with a series ot 
comprest tubercles above. Plastron with median and lateral fontanels. 

Type: Toxochelys latiremis Cope. 



164 FOSSIL TURTLES OF NORTH AMERICA. 

The known species of this genus, 7 in number, are from the Niobrara deposits of Kansas. 
All these species except T. hauri Wieland are based on parts of the skull ; and this portion 
of the skeleton is more commonly found than even the carapace, a rare circumstance in the 
case of fossil turtles. However, the greater part of the shell and limbs is known from two or 
three of the species. 

From studies made on this genus some years ago (Field Columb. Mus. Pubs., Zool. ser. 
I, 1896, p. loi) the writer concluded that the position of this genus is near the Cheloniidae, but 
with evident relationships to the Chelydridae, constituting a distinct family, which is to be 
called, as Baur has proposed, Toxochelyidas. This conclusion has been confirmed by more 
recent investigations made by Case, Wieland, and the present writer. The resemblances to 
Chelydra are to be found especially in the anterior portion of the skull, in the structure of the 
carapace, in the humerus and femur, and in the tuberculated tail. 

The roof of the mouth is practically identical with that oi Chelydra except that the palatine 
extends forward to articulate with the vomer in front of the choanae. The masticatory surfaces 
of the two are equally flat, the cutting-edges of the maxilla are low in both, the choanae are 
placed well forward and are not underfloored by processes from the palatines; and there are 
in both genera large palatine foramina. On the other hand, as in the Cheloniidae, the tympanic 
cavity has not yet entered the squamosal bone, the notch in the hinder face of the quadrate 
remains open, and the back of the skull is extensively rooft over by the parietal, postfrontal, 
and squamosal bones. As regards the carapace, it is evident that the nuchal resembles 
more that of the Cheloniidae, it having had no such long costiform processes as we find in the 
Chelydridae. Again in the presence of a surface for articulation with the spine of the eighth 
cervical, as determined by Wieland, the nuchal resembles more that of the Cheloniidae. There 
were 1 1 peripherals, as in Chelydra and most Cheloniidae. The costal plates were less developt 
than in the Chelydridae, even less than in any living Cheloniidae, so that there are extensive 
fontanels at the sides of the carapace. The elements in the midline appear to have resembled 
more those of Chelydra, but there were peculiarities. There was a prominent carina, which at 
intervals rose into comprest tubercles. The latter were distinct bones, which rested on the 
contiguous portions of two neurals or suprapygals. The first rested on the first neural; the 
second, on the second and third; the third, on the fourth and fifth; the fourth, apparently 
on the seventh and eighth or on the eighth peripheral and the first suprapygal. If the fourth 
was placed on the seventh and eighth neurals a fifth tubercle rested on the second suprapygal. 
Wieland has named these ossicles "epineural spines," but they are hardly to be thus homol- 
ogized with the epineural bones of fishes. They were continued backward on the upper 
surface of the tail as a series such as we find on the tail of Chelydra. The position of all these, 
except the most anterior, was described and figured by the writer in 1898 (Amer. Naturalist, 
XXXII, p. 936, fig. 2). Dr. Case was the first to observe the presence of one of these bones. 
Wieland in 1905 (Amer. Jour. Sci., xx, p. 331) describes a small bone on the first neural 
which probably represents the first of this series of ossicles. Wieland in 1896 (Amer. Jour. 
Sci., II, p. 400) suggested that Archelon may have borne a series of dorsal spines; but as those 
spines were believed to be horny and their existence only hypothetical, their discovery has 
nothing to do with that of the bony spines. The writer has elsewhere presented his reasons 
for believing that these tubercles represent the original dermal skeleton of the Testudines, 
now retained only by Dermochelys (Amer. Naturalist, xxxil, 1898, p. 929). 

The writer presents here a description and figures (plate 30, figs, i, 2) of a portion of a 
carapace belonging to an undetermined species of this genus, remains which were collected 
by Mr. H. T. Martin in Gove County, near Monument Rock, Kansas. Since this carapace 
was not accompanied by any part of the skull, it was not possible to identify it specifically. 

The specimen furnishes 15 peripherals, some fragments of costals, and a series of median 
elements, of which 2 appear to be suprapygals. The median line of the carapace was occupied 
by a strong and sharp keel. Anteriorly the right and left sides of this keel make about a right 
angle with each other, but posteriorly they meet at a smaller angle, so that the keel is high and 
sharp. At intervals the keel rises into comprest tubercles. These were in all cases originally 
distinct bones, but most of them, especially posteriorly, have become co-ossified with the 
supporting bones. The first neural appears to be wanting, together with the nuchal.^ There 
is present i neural which does not furnish satisfactory contact with any of the others. There 



TOXOCHELYID^. 



165 



are 3 others joined in their natural relation, and 3 more joined together and the hinder- 
most united with the suprapygals. The single neural must belong in front of all the others. 
It can not be the first one, because it is too thick in front for the nuchal, in case this was as 
thin behind as in the genus generally; also because it is not crost by the sulcus separating the 
first from the second vertebral scute. It can hardly be anything else than the second neural. 
At the hinder end of the upper surface there is a half-facet for another bone, one of the series 
of ossicles mentioned above. The neural which is regarded as the third has on its anterior 
end a half-facet which completes the one on the supposed second neural. Behind this facet 
is a sulcus, believed to be the one which divides the first from the second vertebral scutes. 
The fourth neural has no tubercle of its own, but its hinder end supported a small part of 
the tubercle which belongs to the fifth neural. This tubercle has a length of 20 mm. Behind 
it is the sulcus which passes between the third and the fourth vertebral scutes. The tubercle 
is wholly co-ossified with the bones on which it rests, but there are traces of the sutures. The 
sixth neural is sharp along the midline, while its sides slope steeply, like a high-pitcht roof. 
The seventh neural is short and closely joined to the eighth. A long and strongly comprest 
tubercle occupies nearly the whole length of both these neurals and appears to be co-ossified 
with both, only traces of the sutures remaining. 

The suprapygals are co-ossified. The first is sharply rooft, while the next one has a rather 
high and comprest tubercle. The anterior suprapygal appears to have been expanded on 

each side, but the expansions are broken away. The sulcus 
between the fourth and the fifth vertebral scutes doubtless 
crost behind the tubercle on the second suprapygal. The 
pygal is represented in plate 30, fig. I. Its height is 14 mm.; 
its width from side to side, 27 mm. Its upper, or anterior, 
border appears to have articulated with a suprapygal which 
is now missing. The upper surface of the pygal is longitudi- 
nally grooved, while the inferior has a more extensive longi- 
tudinal channel. This pygal is quite different from that 
of the type of T. stenopora. The dimensions of the neurals 
and suprapygals are shown in the accompanying table. 
It is evident that there were 1 1 pairs of peripherals, as 
in most turtles. The two anterior are narrow and thin. These are followed by 4 others which 
are thicker and broader, and these again by others which are thin. The table gives the 
dimensions of the peripherals present. The width is taken at the front end. 

The anterior end of the first peripheral is obhque for articulation with the nuchal. The 
third and the succeeding peripherals to the ninth inclusive have each a pit for a corresponding 
rib-end. The tenth has no pit. The eleventh is not present. Since the hinder end of the 
tenth peripheral is 19 mm. wide and the articular end of the pygal only 12 mm. wide, it follows 
that the eleventh was considerably wider at one end than the other. All the peripherals are 
crost by shallow sulci. 

Dr. Wieland has represented (Amer. Jour. Sci., xx, 1905, p. 335, fig 6; here reproduced 
as fig. 229) the rib-end of the eighth costal as entering a pit in the anterior end of the eleventh 

peripheral. The end of the rib was not present and it is 
stated that the rib-pits are all small. In the specimen 
figured by Dr. Case (Univ. Geol. Surv. Kans., iv, 1898) 
the eighth costal comes down to a thin edge and there 
appears to have been no rib-end. Moreover, Case states 
that the eleventh peripheral has no groove nor pit for a 
rib. At my request Dr. C. E. McClung, of the University 
of Kansas, examined this specimen. He finds the pygal 
and the eleventh peripheral in their natural positions and 
the eighth costal with a sharp border and no trace of a 
rib. Case is probably in error in representing the rib of 
the seventh costal plate as going to the tenth peripheral. 
The plastron appears to have resembled quite as much that of the Cheloniidae as it did that 
of Chelydra. As in the former family, that part of the plastron which lay between the fore and 



Element. 


length. 


Width. 




1 

27 


25 




i8 


23 




18 


22 




28 


M 




22 


20 


7 


'3 


18 


8 


10 


>5 


1st suprapygal... 


24 




zd suprapygal... 


•1 31 


13 



Peripherals. 


Length. 


Width 
upper face. 


Thickness. 


, 


»S 


II 




2 


16 


II 




3 


30 


8 


12 


4 


33 


15 


'5 


s 


36 


12.5 


•5 


6 


38 


•5 


10 


7 


36 


15 


8 


8 


3* 


16 


5 


9 


33 


'5 


S-5 


10 


3» 


16 


7-5 



i66 



FOSSIL TURTLES OF NORTH AMERICA. 



hind legs was much broader than it is in the case of Chclydra; and, as in the sea-turtles, there 
was a fontanel between the outer end of the hyoplastron and hypoplastron. There was also 
an extensive umbilical fontanel. The bones of the right and left sides were joined along the 
midline more like those of Chelydra than like those of the Cheloniidae. The epiplastron and 
entoplastron are figured by Wieland (Amer. Jour. Sci., xx, p. 336, figs. 7, 8). The former are 
slender, the latter broad and lance-shaped. The xiphiplastron, as represented by that of 
T. stenopora (Case, op. cit., plate Ixxx., fig. 5), is slender and apposes digitations to its fellow. 
Cervical vertebrae have been figured by Dr. Case (op. cit., plate Ixxxiii, figs. 2-4). These 
were more or less injured, being comprest laterally. A more complete series is in the Marsh 
collection at Yale, and these have been described by Dr. Wieland (Amer. Jour. Sci., xiv, 1902, 
p. 102). According to this author, the anterior 5 have their articular ends fashioned as in 
Chelydra and the great majority of turtles; that is, the first is composed of 4 bones; the 
centra of the second and third are convex in front and concave behind; that of the fourth is 
convex at both ends, as in turtles generally. The next four centra are concave at the anterior 
ends, convex at the posterior. Toxochelys differs from modern Cheloniidae in not having the 
double concavities developt on the anterior end of the last cervical. The specimen furnishing 
these cervicals was not accompanied by the carapace, so that we can not estimate the length of 








^ / 




x> 



Fig. 200. — Toxochelys latiremis. Front limb. X .28. Specimen in Yale Univ. coll. 

fl, head of humerus; fc, radial process; c, ulnar process; cen, centrale; e, ectepicondylar groove; £, entocondyle; 
hunty humerus; intj intermedium; pj pisiforme; rad^ radius; «/, ulna; u/n, ulnare; I, II, etc., metacar- 
pals; I, 2, 3, etc., distal carpal bones. Figure by Wieland. 

the neck relatively to the shell. The estimated length of the neck is 226 mm. The skull was 
1 14 mm. to the occipital condyle. 

Regarding the caudal vertebrae little that is certain is known. It is not at all improbable 
that the vertebrae which were described by Cope under the name Cynocercus incisus belong to 
Toxochelys. Two caudals are in a small collection of bones received from the University of 
Chicago, with the catalog number 230 and belonging to Toxochelys latiremis. The centrum 
of one is 18 mm. long. These vertebrae probably belonged toward the end of the tail. They 
are procoelous and possess short lateral processes. In general these vertebrae resemble those 
of Cynocercus, but the cup is deeper and without sign of the perpendicular incision seen in 
Cynocercus, and the ball is more prominent. 

The coraco-scapular arch is more like that of the sea-turtles than like that of the snappers. 
The coracoid is long, narrow, and spatulate. A considerable neck is interposed between the 
glenoid fossa and the base of the proscapular process. 

The fore limb is best known from a specimen in the collection at Yale (fig. 200), which 
has been described by Dr. Wieland (Amer. Jour. Sci., xiv, 1902, p. 95, fig. i). The humerus 
has also been figured by Dr. Case. Dr. Leidy also has figured the proximal end of the humerus 
of what is no doubt a member of this genus (Cont. Ext. Vert. Fauna West. Terrs., 1873, plate 
xxxvi, fig. 17). For a figure of the humerus of T. latiremis 'see fig. 200, shown above. This 
specimen was accompanied by the lower jaw, and its identification thus made certain. 

The humerus of Toxochelys is regarded by Dr. Wieland as representing the form which 
he has called "thalassoid, " especially because he believes that the radial process has descended 
lower on the shaft than it is in Chelydra and that the ulnar and radial processes have moved 



TOXOCHELYID^.. 



167 



nearer their respective borders of the huinerus. To the present writer the principal changes 
which have affected the thalassic and parathalassic humeri, as represented by Caretta and 
Dermochelys, are to be found in the straightening of the shaft; the change of the head from a 
position looking upward, in the natural position of the bone, to one looking toward the median 
plane of the animal; the descent of the radial process, on the shaft; the transference of this 
process, or of a component of it, toward the radial border; and the removal of the condyles 
for the radius and ulna and of the ectepicondylar foramen or groove toward the ulnar border of 
the bone. Of all these changes none seems to have taken place in Toxochelys, except a slight 
descent of the radial process. In every other respect the bone retains the characteristics of 
ChelyJra. 

In many other features the fore limb of Toxochelys has made approaches to the flipper of 
the marine turtles, as Dr. Wieland has shown. The ulna, as compared with that of Chelydra, 
has become shorter relatively to the humerus while the radius has 
become longer, as it has also to a greater degree in Caretta. The ulna 
has become shorter than the radius, and the third and fourth fingers 
have become greatly elongated; but in these respects it is far behind 
Caretta. The first and second fingers retain about the same ratio to 
the humerus that they have in Chelydra. Taken altogether, the limb 
may be regarded as standing between that of Chelydra and the sea- 
turtles but nearer to that of Chelydra. From the fact that the head of 
the humerus had the position that it has in the freshwater turtles and 
that the phalanges possest well-developt condyles we may be quite cer- 
tain that the species of Toxochelys had no difficulty in getting about 
on the land. 

The first and second fingers of Toxochelys were composed of 
phalanges which were much stouter than those of the other fingers. 
The terminal phalanges were encased in horn and formed strong 
curved claws. The other fingers did not probably extend beyond the 
border of the skin. Dr. Case (op. cit., plate Ixxxii, figs, i, 2) repre- 
sents the first finger as having 3 phalanges. This figure is evidently 
that of the second finger. 

The following measurements are taken from Dr. Wieland's des- 
cription of the fore limb in Yale University Museum (fig. 200) : Length 
of humerus, 135 mm.; radius, 75 mm.; ulna, 66 mm.; total length 
of the first finger, 65 mm.; of second finger, 95 mm.; of third finger, 
estimated, 130 mm.; of fourth finger, estimated, 135 mm.; of fifth finger, estimated, 90 mm. 
The pelvis is somewhat more like that of Caretta than like that of Chelydra. Dr. Case 
has given figures of the ilium (op. cit., plate Ixxxi., fig. 8) and of the ischium (op. cit., pi. Ixxxii, 
fig. 6). The antero-lateral processes of the pubis are broader than they are in Chelydra. 
The femur is not an uncommon bone in collections of Toxochelys materials. Figures of 
the bone are presented hy Case (op. cit., plate Ixxxi) and Leidy (op. cit., plate xxvi, fig. 18). 
Unfortunately the bone is usually crusht, so that its exact form is questionable. It is certain, 
however, that the greater and the lesser trochanters were separated by a deep fossa, as Case 
has described the bone. This fossa was probably like that found in Chelydra. In Caretta 
and again in Testudo this fossa is nearly obsolete. Case believed that the femur was a weaker 
bone than the humerus. This view is probably correct, and is corroborated by the relative 
izes of the humerus and femur figured by Leidy. It is not certain, however, that these bones 
belonged to the same individual. In Chelydra the femur is the longer bone. 

The tibia and fibula are not well known. There is presented in fig. 201 a portion of the 
hinder limb in the possession of the author and believed to belong to Toxochelys. The tibia 
and fibula are elongated and slender, more like those of Chelydra than like those of Caretta. 
Four tarsals are present. The metatarsal is probably that of the first toe. Case (op. cit., p. 378) 
describes the hind foot of an incomplete specimen, but the error is made of assigning four 
phalanges to the first digit. The digit may have been the second, including the metatarsal. 
The terminal claw was strong and much curved. The phalanges of the remaining digits were 
longer and slenderer, and the terminal one did not support a claw. 




Fig. 201.- 

sp. indet. Tibia, fib- 
ula, and some foot 
bones, xi. 



i68 



FOSSIL TURTLES OF NORTH AMERICA. 



Key to Species of Toxochelvs. 
A. Species based on skull. 

a. Symphysis of lower jaw short, about one-fifth of length of lower crushing-surface of jaw. 
b. Snout rather pointed. 

c. Jaws slender and weak; symphysis thin, sloping on upper surface latiremis 

cc. Jaw rather heavy; the upper surface of the symphysis horizontal serrtfer 

hb. Snout broad and rounded hrachyrhina 

aa. Symphysis long, at least one-third the length of the crushing-surface. 

d. Nasal opening narrow; upper surface of the symphysis sloping stenopora 

dd. Nasal opening normal; symphysis flat above. 

e. Skull as broad as long elkader 

ee. Skull longer than broad procax 

A A. Species based on shell only bauri 




Figs. 202-205. — Toxochelys latiremis. Skulls and lower jaw. Xj. 

202. Upper view of front of skull. No. 1496 A.M.N. H. 

Z03. Upper view of skull. No. 1497A. M. N. H. at, atlas; ^iv, axis; s;, squamosal. 

204. Lower view of same skull as preceding, at, atlas; ax, axis; qu, quadrate; sq, squamosal. 

205. Dentary portion of lower jaw, with section along the symphysis. No. 1497 A, M. N. H. 

Toxochelys latiremis Cope. 

Figs. 200, 202-206. 

Toxochelys latiremis. Cope, Proc. Acad. Nat. Sci. Phila. 1873, p. 10; Vert. Cret. Form. West, 1875, 
pp. 98, 260, pi. viii, figs. I, 2; Proc. Amer. Fhilos. Soc, xvii, 1877, p. 176. — Hay, Pubs. Field 
Columb. Mus., Zool., I, 1896, p. loi, pis. xiv, xv; Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 442; 
Bull. Amer. Mus. Nat. Hist., xxi, 1905, p. 177. — Case, Univ. Kansas Geol. Surv., iv, 1898, p. 371, 
plate Ixxix; plate Ixxx, figs, i, 2; .'plate Ixxxi, figs. 1-8, 10-13; -'p'ste Ixxxii, figs, i, 2; plate Ixxxiii, 
figs. 2-4. — ^Wagner, Kansas Univ. Quarterly, vii, A, 1898, p. 201, fig. I.— Wieland, Amer. Jour. 
Sci. (4), xiv, 1902, p. 95, figs. 1,2.^ 

Cynocercus incisus, Leidy, Cont. Ext. Vert. Fauna West. Terrs., 1873, P- ^79, plate xxxvi, figs. 17-21. 

The type of the present species consists of a portion of the lower jaw and a coracoid, of 
the Cope collection of reptiles and fishes, and is now in the American Museum of Natural 
History, New York, having the number 2362. The specimen was collected by Professor 



TOXOCHELYID^. 



169 



B. F. Mudge, in the Niobrara deposits of Kansas, near the forks of the Smoky Hill River. 
The animal was a large one, since the mandible, from the symphysis to the angle of the jaw, 
measures 157 mm. In 1877, as cited in the synonymy, Professor Cope came into possession 
of 2 nearly complete skulls, which he identified as belonging to T. latiremis, and these he 
described. These skulls are now in the American Museum and bear respectively the numbers 
1496 (fig. 202) and 1497 (figs. 203, 204). The latter (and probably both specimens) was 
collected somewhere along the Smoky Hill River. A comparison of the lower jaws of these 
skulls with that of the type makes it certain that the former were correctly referred. 

The first publisht figure of the skull of this species was made by Hay, as cited. This 
skull lackt the lower jaw; but a comparison with the skulls described by Cope reveals no 
differences. Other skulls have been figured by Case and Williston, as cited. 

This appears to have been the commonest turtle in the Niobrara beds of Kansas, yet many 
parts of its skeleton remain unknown. The size attained was considerable. If the length of 
the coracoid bore the same relation to the length of the carapace that subsists between these 
bones in Chelydra or Caretta, the carapace must have been about a meter in length. It may be 
remarkt here that the coracoid of Cope's type was 225 mm. long, that author's statement 
that it was 250 mm. being incorrect. The ramus of the mandible has a length of 157 mm., so 
that the skull, from the tip of the snout to the occipital condyle, was close to 160 mm. 

The skull of this species is broad posteriorly. 
In front of the quadrates the width is gradually 
reduced, so that the head is wedge-shaped and 
the snout pointed. Altho all the skulls yet found 
are considerably flattened by pressure, it is quite 
certain that the head was rather deprest, more 
like that of Chelydra than like that of any of the 
living Cheloniidae. The supraoccipital is long. 
The temporal region is rooft over about as in 
Caretta, and the squamosal appears to have come 
into narrow contact with the parietal. The orbits 
lookt upward and outward, resembling more 
those of Chelydra than those of the Cheloniidae. 
The opening of the anterior nares is large, con- 
trasting strongly with that of T. stenopora. The 
tympanic cavity did not extend into the squa- 
mosal, but had the stage of development seen in 
the loggerhead. The cutting-edge of the maxilla 
is moderately high anteriorly, but becomes very 
low at the hinder end. As seen in profile, it is convex. There is a rough ridge on the palatine 
near its articulation with the maxilla. The alveolar, or masticatory, surface of the upper jaw is 
somewhat concave from side to side. Including the ridge on the palatine, this surface is not 
so wide as is the fossa containing the choanae. There are large posterior palatine foramina. 
The narrowest portion of the palate, across the pterygoids, is rather wide compared with the 
other species, and is flat. More posteriorly each pterygoid bears a groove which is directed 
outward and backward toward the hinder border of the quadrate. 

The lower jaw is relatively weak. The alveolar surface is narrower than in the other 
species in which it has been observed. Fig. 205 represents the lower jaw belonging to 
specimen shown in figures 203 and 204. The outer edge is sharp and rises somewhat above 
the inner edge. The latter rounds off into the inner face of the jaw, which face is in no 
way hidden by the surface referred to. At the symphysis the alveolar surface extends back- 
ward little more than one-half as far as does the lower face of the bone. The tip of the jaw is 
slightly beakt. 

Notwithstanding the fact that a considerable number of skulls of this species have come 
to light, portions of the carapace or plastron are rare. Wieland (as cited) mentions portions 
of the carapace and plastron in Yale University, but he does not describe them. 

The cervical vertebra and some caudals have already been described in the discussion 
of the genus. No other vertebrae are known. 




Fig. 206. — Toxochelys lattremis. Scapula and 
coracoid. Xj. Redravpn from figures by Case. 



170 



FOSSIL TURTLES OF NORTH AMKRICA. 



For description of the shoulder-girdle (fig. 206, from Case) and remarks thereon, see page 
166. The structure of the anterior limb has also been described and illustrated. 

No pelvis definitely known to belong to this species has been described. References to 
femora supposed to belong to this species have already been given, but these may have belonged 
to other species, as T . procax or T . brachyrhina. Case (op. cit., p. 378) describes a hind foot 
which he refers to T. latiremts. This has already been mentioned on page 167. 

Wagner has described and figured a portion of a skull of a turtle from the Pierre shales 
of Kansas, which he identifies as T. latiremts. The present writer has not seen this skull. 
The lower jaw figured by Wagner certainly does not belong to T . latiremts. 

Toxochelys serrifer Cope. 

Figs. 207-213. 

Toxochelys serrifer, Cope, Vert. Cret. Form. West, 1875, p. 299. — Hay, Bibliog. and Cat. Foss. Vert. 
N. A., 1902, p. 442; Bull. Amer. Mus. Nat. Hist, xxi, 1905, p. 178, figs. 1-7. 

The type of this species is No. 1835 of the Cope collection of reptiles and fishes in the 
American Museum of Natural History, New York. It consists of the greater portion of both 
maxillae, the left dentary, the greater portion of the pterygoids, the right quadrate, the frontals 





212 



Figs. 207-212. — Toxochelys serrifer. Portions of skull of type. Xi. 



207. Left dentary. Shows cutting-edge and grinding- 

surface. 

208. View of inner face of dentary. 

209. Symphysis of lower jaw. 



210. Cutting-edge and grinding-surface of upper jaw. 

mx, maxilla; pat, portion of palatine. 

211. Base of skull, fcoc, basioccipital; />f, pterygoid. 

212. Upper aspect of skull, /r, frontalsj pa, parie- 

tal; prjj prefrontal. 



and prefrontals, and two peripherals. They were collected somewhere in the Niobrara deposits 
of Kansas by Professor Merrill, in 1865. 

The dentary (figs. 207-209) had not yet become co-ossified with its fellow. Its length is, 
as Cope states, 48 mm.; its width above, 9 mm.; the depth of the inner face, 7 mm. Longi- 
tudinally the alveolar surface is more strongly concave than in T. latiremts. Near the sym- 
physis the surface is considerably concave transversely, but posteriorly it is nearly flat. The 
inner border of this surface is nearly on the same level as the outer. At the symphysis (fig. 209) 
the alveolar surface extends nearly as far backward as does the lower face of the bone. The 
inner face of the dentary is occupied by a broad groove. The length of the alveolar surface of 
the symphysis is 9 mm. 

Slightly more than the posterior half of each maxilla (fig. 210) is present. The alveolar 
surface is flat, and the cutting-edge retains its height to its hinder end. In T. latiremis the 
height becomes reduced posteriorly. The pterygoids (fig. 211, pt) present no peculiarity. 
Where narrowest the portion of the palate formed by the pterygoids is 15 mm. wide. The 
quadrate does not differ from that of T. latiremis, except that the articular surface for the 



rOXOCHEl.YID^. 



171 




Fig. 21^ — Tosochehs ser- 
rijer. One peripheral 
and part of another. 
XI. 



lower jaw is much smaller. This surface is triangular, the inner lobe seen in T. latiremis 
being greatly reduced in T . serrifer. 

The interorbital space (fig. 212) had a width of 16 mm. where narrowest. The groove on 
the under surface of the frontals for the olfactory nerve is relatively narrower than in T. 
latiremis, in which the groove is nearly one-third as wide as the interorbital space; whereas, 

in T. serrifer it is only about one-sixth the width of that space. The 
anterior borders of the prefrontals are broken away, so that the 
width of the anterior narial passage can not be determined. It is 
certain, however, that the nasal cavity itself had the lateral extent 
that it had in T. latiremis. 

An estimate shows that the length of the skull from the snout to 
the occipital condyle was about 80 mm. 

Two adjacent peripheral bones are present, probably the left 
eighth (fig. 213) and the ninth. The eighth is 40 mm. long and 32 
mm. wide, the ninth 43 mm. long and 32 mm. wide. Each is notcht 
just behind the widest portion and here the width of the eighth is 25 
mm., of the ninth 27 mm. The thickness of the inner face is nearly 
7 mm., and at the hinder end of this face is a pit for a rib. 

The specimens which were referred to this species by Case (Univ. 
Geol. Surv. Kan., iv, p. 379) are described as T. stenopora. From 
the latter species T . serrifer differs in having a dentary with an 
alveolar surface much wider in proportion to its depth, and not beakt 
at the tip. 

It is evident that the skull (and probably the whole skeleton) of T. serrifer was much larger 
than that of T. stenopora. This makes it all the more remarkable that the dentary of the 
former is relatively so short and that the depth of T. stenopora is so great. It seems not im- 
probable that the carapace and part of the plastron described by Wieland as T. baurt will 
prove to belong to the present species. 

Toxochelys brachyrhina Case. 

Plate 31, fig. 1. 

Toxochelys brachyrhinus , Case, Univ. Geol. Surv. Kansas, iv, 1898, p. 378, pi. Ixxxiv, figs, i, 2.— Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 442; Bull. Amer. Mas. Nat. Hist., xxi, 1905, p. 177. 

The type of this species is a skull, the property of Kansas University, and bearing the 
number 1 21 2. Dr. Case's description of it is exceedingly brief. The character which he gives 
as distinguishing it from T. latiremis is the much blunter snout. Case's fig. I of his plate is 
three-fourths of the natural size; and, while the form of the skull is shown, the details are not 
well represented. His fig. 2 is a restoration of the size of nature, but it does not indicate the 
sutures; likewise it represents the anterior half of the skull as somewhat too broad. 

The skull of this species appears to be distinguisht from that of T. latiremis in being 
narrower posteriorly in relation to the length and in having a broader snout. Another distin- 
guishing character seems to be found in the narrower posterior region of the palate. In the 
case of a large specimen of T. latiremis, 130 mm. from the snout to the occipital condyle, the 
pterygoid portion of the palate, where narrowest, is 36 mm. wide. In the type off. brachyrhina, 
1 17 mm. to the occipital condyle, the palate is only 20 mm. wide. The interorbital space also 
is relatively narrower than in T. latiremis. In the specimen of the latter referred to, the space 
between the orbits is 24 mm. wide, in T. brachyrhina, only 19 mm.— too great a difference to 
be due to difference of size alone. 

The following measurements are given of the type specimen: 

Millimeters. 

Length from the snout to the occipital condyle n? 

Length to extremity of supraoccipital bone I34 

Distance between the outer faces of quadrates 9° 

Distance between outsides of squamosals 94 

Width at hinder borders of orbits °° 

Width at front of orbits 5° 



172 



FOSSIL TURTLES OK NORTH AMERICA. 



The anterior nares do not appear to have been different from those of T. latiremis. As 
seen in the type and the figures here presented, the quadrates have been squeezed forward 
somewhat. The lower jaw is present, but is so closely prest against the roof of the mouth 
that its alveolar surface can not be seen. So far as can be judged, it is not greatly different 
from that of T. latiremis; but the symphysis is evidently shorter. It is very desirable that 
this surface should be seen, in order to distinguish this species clearly from T . serrifer. 

In explanation of the figure, it should be said that the inner nares are hidden by some 
fragments of bone, probably of the hyoids. 

The type was found in the Niobrara deposits of Gove County, Kansas. 




220 



Figs. 214-220. — Toxochelys stenopora. Portions of type. 



214. Dentary portion of lower jaw. Xi. 

215. Left dentary, showing inner face. Xi. 

216. Section along symphysis of lower jaw. Xi. 

217. Upper aspect of skull. Xi. /r, frontal ; mx, 

maxilla ; pa, parietal ; pal, palatine ; pmx, 
premazilla ; prf, prefrontal ; pt, pterygoid . 



218. View of palatal surface of skull. Xi.' 

219. Supraoccipital. Xi. 

220. Left hyoplastron, hypoplastron, and xiphiplastron 

of type. X^. Redrawn from figure by Case. 



Toxochelys stenopora Hay. 

Figs. 214—220. 

Toxochelys serrifer. Case, Univ. Geol. Surv. Kansas, iv, 1898, p. 379, plate Ixxx, figs. 3-9; plate Ixxxii, 
figs. 4, 5; plate Ixxxiii, fig. i. — Hay, Amer. Naturalist, xxxil, 1898, p. 935, figs. 1-3; Bibliog. and 
Cat. Foss. Vert. N. A., 1902, p. 442, in part. — Williston, Trans. Kansas Acad. Sci., xvil, 1901, 
p. 198. 

Toxochelys stenoporus, Hay, Bull. Amer. Mas. Nat. Hist., xxi, 1905, p. 180, figs. 8-12. 

The present writer is not able to agree with Dr. Case in his identification of the testudinate 
remains belonging to the University of Kansas which he has described and figured as Tox- 
ochelys serrifer. The type of Cope's T. serrifer belongs to the American Museum of Natural 
History and was not accessible to Dr. Case when he was studying the fossil turtles of Kansas. 

Of the bones figured by Case, the skull (plate Ixxxii, figs. 4, 5), the marginals (fig. i, 
plate Ixxxiii), and the hyoplastron (fig. 3, plate Ixxx), are markt with the number 2060; while 
the elements furnishing fig. 4 of the last-named plate, and the neurals and suprapygal of fig. i. 



1 

Dimension. 


Toxochelys 
serrifer. 


: 

Toxochelys r 
stenopora, \ 

33 
6-S 

7 

9 

11.5 


Length from tip of jaw to hinder end 


48 
9 

7 

8 

10 


Width of grinding surface 

Width of inner face at middle of 

length 

Whole depth of jaw at middle 

Length of symphysis on upper surface 



TOXOCHELYID^. 17-1 

plate Ixxxiii, belong to No. 1270. There appears to be no reason for doubting that these bones 
all belong to the same species. 

The principal differences between the present species and Cope's T. serrifer must be sought 
in the form of the lower jaws and of the peripheral bones. Unfortunately we can not determine 

the form of the anterior nares of T. serrifer. 
The lower jaw of T. serrifer shows no indica- 
tions of a beak, while that of T. stenopora 
(figs. 214-216) is plainly beakt. Case recog- 
nized this difference. The table herewith 
presents the dimensions of the two jaws. 

It is seen from these measurements that, 
although the lower jaw of T. stenopora, as 
represented by the masticatory surface, is 
much shorter than that of T. serrifer, the jaw 
is nevertheless deeper, the inner face of equal 
depth, and the symphyseal line of the masticatory surface longer. The width of the inner 
face of T. stenopora may be somewhat greater than the figures indicate, since there is evi- 
dence of some downward crushing. The symphyseal line above slopes downward and back- 
ward in T. stenopora; in T. serrifer, it is nearly horizontal. 

The peripherals of T. serrifer are much broader and flatter in proportion to their length 
than in T. stenopora. Thus, in comparing what appear to be the eighth peripherals, we find 
that of T. serrifer measuring 49 mm. in length and 32 mm. in width, while that of T. steno- 
pora is 23 mm. long and 10 mm. wide. 

The bones bearing the number 2060 of Kansas University museum are made the type 
of the present species, and in case it should be found that the skull and the other bones of 
2060 are not all of the same species, the former is to be regarded as the type. 

As will be seen from the figures (figs. 217, 218), the skull has been damaged, especially the 
hinder portion. Nearly the whole of the roof of the temporal region is missing. The quadrates 
and the supraoccipital are present, but detacht from the rest of the skull. Dr. Case's figures 
represent the skull as larger by one-half than the originals; but this has probably been due to 
the failure of the engraver to reduce the original drawings. 

The skull was evidently short and broad. The distance between the hinder ends of the 
maxillae equaled the distance from the snout to the middle of the basisphenoid; whereas in 
T. latiremis the distance between the extremities of the maxillae extends only to the narrowest 
portion of the pterygoids. The length of the skull to the hinder border of the basisphenoid is 
46 mm.; to the occipital condyle was probably about 10 mm. more; while the length to the 
hinder end of the supraoccipital bone was about 82 mm. The palate, where narrowest, is 
10 mm. wide; the interorbital space, 13 mm. The alveolar surface of the upper jaw, including 
the rough ridge on the palatine, is relatively broader than in T. latiremis, being contained in 
the length of the cutting-edge 3 times. In T. latiremis it is contained 4 times. This increase 
in the width of the surface appears to be at the expense of the fossa for the choanae, which is 
but little wider than the surface referred to; whereas in T. latiremis the fossa is much wider. 
In the wideness of the alveolar surface and the narrowness of the fossa the present species 
resembles T. procax. 

There were without doubt posterior palatine foramina, as in the other species of the genus. 
That which distinguishes this species from all others of the genus, so far as known, is the 
narrowness of the anterior nares. This slit-like opening is evidently natural, or due only very 
slightly to any compression during fossilization. The skull is flattened somewhat by pressure, 
from which condition we may conclude that the narial opening originally had possibly a more 
perpendicular position than at present. 

A portion of one parietal bone is among the remains of the skull. It presents a part of 
the roof of the temporal region. The supraoccipital (fig. 219) has a length of 35 mm. and a 
maximum height of 16 mm., being thus relatively long and high. 

This skull is accompanied by the pygal and nearly all of the peripherals of one side. Some 
of these have been figured by Dr. Case (op. cit., plate Ixxxiii, fig. i). The pygal has a sharp 
posterior border and a rounded anterior border. From the latter there springs a process which 



174 



FOSSIL TURTLES OF NORTH AMERICA. 



has joined the hindermost supiapygal. Above and below, the pygal is broadly grooved from 
front to back. The most anterior peripheral is thin and narrow. The second is only slightly 
wider. The third has its inner face more developt and possesses a pit which received the 
extremity of the rib of the first costal plate. The inner, or costal, face of the succeeding periph- 
erals increases in breadth, until a section of the bone is a nearly equilateral triangle; then 
the face is reduced, so that at about the eighth the bone has grown quite thin and flat and 
relatively broad. Each peripheral, except the first and the second, has a pit for the reception 
of a rib-end, until we come to the tenth. 

Ordinarily in turtles the eighth costal plate sends its rib to the tenth peripheral, but in 
Toxochelys the eighth costal plate is short and its rib does not extend beyond the border of the 
plate. As in Chelydra and most other turtles, there is no rib-end reaching the eleventh periph- 
eral. In the Cheloniidae the rib of the eighth costal plate is turned backward to this periph- 
eral, one of the more anterior peripherals not receiving a rib. However, Wieland represents 
the rib of the eighth costal plate as entering a pit in the eleventh peripheral. See fig. 235 of 
the present work. 

No. 1270 of the Kansas University museum furnishes a number of costal plates, a few 
neurals and the anterior suprapygal bone. These are represented in Case's figure already 
referred to. According to the present writer's views, another peripheral ought to be inserted 
between the last one of that figure and the pygal; and there was almost certainly at least one 
suprapygal behind the one there represented. The neural which Dr. Case has called the ninth 
is certainly the eighth, since it has articulated with it the eighth costal. Resting partly on this 
neural and the first suprapygal is a comprest tubercle at the base of which is a distinct suture. 
The neural seen in front of the one just referred to is probably in its correct position; but the 
next one in front is certainly wrongly placed, being probably the fifth. The facet on the anterior 
end of the upper surface of the sixth has undoubtedly supported a tubercle similar to the one 
resting on the eighth neural. 

The midline of the carapace of T. stenopora was traverst by a sharp and tuberculated 
keel, such as has been described as occurring in the specifically undetermined species (p. 164). 
As in that form, the more anterior tubercles were connected with their underlying bones by 
open sutures. The elevation of the shell was probably about the same that we find in Chelydra. 

In the figure presented by Dr. Case, the costal plates are probably correctly placed with 
reference to one another. As will be seen, there were large fontanels between the distal ends 
of the ribs. 

The plastron is represented by fig. 220, reproduced from Dr. Case's work so often quoted. 
Nothing is known regarding the entoplastron and epiplastron. There was a large umbilical 
fontanel, while there was, on each side, another fontanel bounded by the peripherals outwardly 
and by the hyoplastron and hypoplastron in front and behind. The lateral digitations of the 
plastral bones did not enter into pits in the peripherals. The median digitations probably 
approacht closely those of the opposite side. A prominent longitudinal ridge on each side 
crost the hyoplastron and hypoplastron. 

Toxochelys elkader sp. nov. 

Figs. Z2I-223. 

Of the type of this species. No. 6137 of the American Museum of Natural History, there 
were secured the skull nearly complete; large portions, perhaps the whole, of the plastron; 
the shoulder-girdles; portions of the pelvis; and apparently one or two peripherals. Excepting 
the skull, the parts have not yet been prepared for study. The specimen was found in the 
Niobrara beds, near Elkader, Logan County, Kansas, by Mr. H. T. Martin, of the University 
of Kansas. 

The skull, like most specimens found in the Niobrara beds, is somewhat crusht. The 
length from the snout to the occipital condyle is 105 mm.; to the end of the supraoccipital 
spine, 143 mm. From the outside of one quadrate to that of the other is loi mm. The outline 
of the skull, from a little in front of the quadrate, is nearly straight to the rather pointed snout. 

Both squamosals (fig. 221) are missing, but it is probable that each sent upward a process 
to the parietal. The latter bones are complete. The jugal extended nearly to the pedicel ot the 



TOXOCHELYID^. 



175 



quadrate. On the right side the whole of the quadratojugal is missing, but on the left most of 
it is present, but crusht. The interorbital space is 22 mm. wide. The orbit has an antero- 
posterior length of 38 mm. The nasal opening is 15 mm. wide. 

The pterygoid portion of the palate (fig. 222), where narrowest, is 20 mm. wide, being 
narrower than in T . latiremis. The distance between the ends of the pterygoid processes is 
46 mm.; whereas, in T. latiremis of the same size, the distance is 53 mm. The postpalatine 
foramina have a diameter of 5 mm.; those of T. latiremis, a diameter of 13 mm. 





Pigs. 221 and 222. — Toxochelys elkaJer. Skull of type. 
221. Upper view. 222. Lower view. 

The choanae are slightly further from the snout than in T. latiremis, the anterior boundary 
being 28 mm. away. This region is constructed much as in T. procax, but the choanae are 
relatively nearer the snout. The triturating surface of the upper jaw is 21 mm. wide, including 
a roughened ridge 5 mm. wide on the palatine. 

The lower jaw (fig. 223) is apparently somewhat crusht downward. It is complete, except 
that both articulars appear to be missing. The triturating surface looks directly upward, is 
slightly concave transversely, and its inner border overhangs the inner face of the bone. The 

surface is 15 mm. wide at the middle of the length, widening 
forward, becoming narrower backward. The symphysis has 
a width of 23 mm., both above and below. 

So far as is to be seen, the plastral bones do not differ 
from those of T. serrifer. One coracoid is observed. The 
length is 85 mm.; the width of the free end, 48 mm. The bone 
is therefore both shorter [and wider Jthan that of T. latiremis. 
Some of the ways in which this species differs from 
T. latiremis have been mentioned; but the lower jaws are 
especially different. In T. latiremis the grinding-surface is 
narrower and it slopes downward and inward toward the inner 
face. 

T. serrifer differs in having the grinding-surface more con- 
cave from front to back, of equal width from end to end, and 
the superior line of the symphysis equal to the width of the 
grinding-surface, and to the lower line of the symphysis. 

In T. stenopora the triturating surface of the lower jaw 
slopes downward and inward to meet the inner face of the jaw. The upper line of the sym- 
physis slopes downward and backward and is somewhat shorter than the lower line. The 
nasal opening is contracted. The length of the prefrontal suture is equal only to one-halt 




Fig. 223. — Toxochelys elkader. 
Lower jaw of type, with section 
at symphysis. X^. 



176 FOSSIL TURTLES OF NORTH AMERICA. 

the interorbital space, whereas in T. elkader the same suture is equal to the whole width of the 
interorbital space. 

T. brachyrhina is a species with a blunter snout, a narrower lower jaw, and a much shorter 
symphysis. The skull is narrower behind in proportion to the length. 

T. procax also has a relatively narrower skull and the choanse are placed further behind 

the snout. 

T. bauri, having been founded solely on portions of the shell, can not be compared with 
any species based on the skull alone. 

Toxochelys procax Hay. 

Figs. 2x4-228. 

Toxochelys procax. Hay, Bull. Amer. Mus. Nat. Hist., xxi, 1905, p. 181, figs. 13, 14. 

The type of the present species is a large, but somewhat damaged, skull which belongs to 
the American Museum of Natural History, New York. Its number is 234. It was obtained 
from Mr. H. T. Martin, who collected it in the Niobrara deposits along the Smoky Hill River, 
in Kansas, in 1901. On the lower surface, the lateral wings of the pterygoids are broken away; 
also the hinder extremity of one maxilla, and a small portion of the palatines. On the upper 
surface, the greater part of the frontals and parietals is gone, as well as the whole of the jugals. 




Figs. 224-228. — Toxochelys procax. Skull and lower jaw. 



224. Upper aspect of anterior portion of skull of type. 

225. Skull of type, showing palatal surface. 

226. Tip of lower jaw, with section (226a) along 

symphysis. No. 234 A. M. N. H. 

227. Tip of lower jaw. No. 220 A. M. N. H. 

228. Dentary bones. No. 2050 Kansas Univ. 

quadratojugals, and squamosals. On the lower jaw there are present a portion on each side 
of the symphysis and the hinder end of one dentary. 

The form of the skull (figs. 224, 225) is like that of 7". latiremis, except that the outlines of 
the maxillse, as seen from below, are nearly straight, until the snout is approacht; whereas 
in T. latiremis the whole outline is convex. The skull is likewise more elongated than that of 
T. latiremis. The interorbital space is 27 mm. wide; and the pterygoids, where narrowest, are 



TOXOCHELYIDiE. 



177 



22 mm. wide, taken together. In T. latiremis, No. 1497 of the American Museum, with skull 
only two-thirds as long as the type of T. procax, the interorbital space is 20 mm. and the ptery- 
goids are 23 mm. T. procax is therefore characterized by a very narrow palate. 

The most important character for differentiating this species from T. latiremis is found in 
the lower jaw. As shown by the symphyseal portions of the dentaries, the alveolar surface is very 
broad, horizontal, and very slightly concave. In the midline this surface extends as far back- 
ward as does the symphysis on the lower side of the jaw; whereas in T. latiremis the alveolar 
surface extends backward little more than half as far as the lower face of the bone. 

From the type of Cope's T. serrifcr this species is likewise distinguisht by the width of the 
symphyseal portion of the alveolar surface. In T. serrifer the surface extends backward nearly 
as far as does the lower surface of the bone; but the width above is contained in the length of the 
alveolar surface nearly 5 times, whereas, in T . procax, it is contained only 2.5 or 3 times. The 
inner face of the dentary is furthermore much deeper proportionally in T. serrifer than in 
T. procax. From T . brachyrhtna this species differs, so far as known, in having a more pointed 
head and a still narrower pterygoid region. The lower jaws of the two can not yet be com- 
pared. From T. stenopora the present species differs in a much wider narial orifice and in the 
character of the lower jaw, as well as in various other respects. T. elkaJer has a relatively 
broader skull and choanae not so far removed from the snout. The lower jaws of the two species 
appear to be greatly alike. 

The length of the skull of the type of T. procax is 165 mm. from the tip of the snout to the 
occipital condyle. The distance between the outer faces of the quadrates is 138 mm. Seen 
from below the skull is wedge-shaped, and the snout rather pointed. The anterior narial 
opening is of the usual form. Little can be said regarding the upper surface of the skull. 

The alveolar surface of the upper jaw (fig. 225) is broad, and a strongly developt and very 
rough ridge starts from the premaxilla and runs backward, first on the premaxilla, then on the 
palatine. Between the anterior ends of these ridges there runs a deep median groove. The 
palatine bones encroach more on the choanae than they do in T. latiremis, so that these orifices 
resemble somewhat those of Chelonta. The alveolar surfaces are fully as broad at the anterior 
ends of the choanae as they are posteriorly; whereas in T. latiremis they widen posteriorly. 
There is a deep pit in the midline on the lower surface of the premaxillae, from which we may 
infer that the lower jaw bore a sharp horny beak. The cutting-edges of the maxillae descend 
but little below the level of the alveolar surfaces. 

The tympanic cavity appears to have had about the same degree of development that we 
find in Caretta. 

At the symphysis (fig. 226) the alveolar, or masticatory surface, extends backward as far 
as does the lower face of the bone, and each measures 32 mm. The alveolar surface is slightly 
concave on each side of a low median ridge, which forks posteriorly. The symphysis has a 
thickness of but 12 mm., which thinness may be due slightly to compression, but this is doubt- 
ful. The groove on the inner face of the dentary continues to the symphysis. Fig. 227 repre- 
sents another jaw fragment in the American Museum. Its number is 220. 

No. 2050 of the Kansas University furnishes the united dentaries of this species (fig. 228), 
but it has belonged to a smaller specimen than the type. A small portion has been broken from 
the tip. The total length of one dentary is 80 mm. The width of the masticatory surface at 
the symphysis is 24 mm., and it extends as far backward as the symphysis does on the lower 
side of the jaw. The thickness of the bone at the hinder end of the symphysis is 9 mm., but 
in life this may have been greater. The masticatory surface is broad and flat, but narrows 
posteriorly. Both the inner and the outer borders are sharp, the latter overhanging the groove 
along the inner face of the bone. The groove just referred to passes forward to the symphysis. 

The writer has been enabled to examine a skull and lower jaw of this species, which belongs 
to the University of Chicago. Its catalog number is 572. The exact locality in Kansas is 
unknown. The skull is 117 mm. long from the snout to the condyle. The upper surface is 
damaged to the same extent as in the type specimen. The masticatory surface of the lower 
jaw extends backward 60 mm. from the tip of the jaw. Anteriorly it is somewhat concave, 
but along the symphysis there is a rather prominent ridge. The thickness of the jaw at the 
hinder end of the symphysis is 10 mm. 

12 



.78 



FOSSIL TURTLES OF NORTH AMERICA. 



Toxochelys bauri Wieland. 

Figs. 229-230. 
Toxochelys btitiri, WiELAND, Amer. Jour. Sci., XX, 1905, p. .^25, plate x, text-figs. 1-8. 

Up to the present time no better carapace of a Toxochelys has been recovered than that 
forming the basis of Wieland's Toxochelys bauri. This specimen forms No. 2823 of the Yale 
University collection. It was found in the Niobrara deposits, near Monument Rocks, Gove 
County, Kansas. It furnishes all the neurals, and the nuchal; large portions of all the costals 
of the right side, except the fifth; the proximal ends of all the costals of the left side; all the 
peripherals of the right side, except the fifth to the eighth inclusive; all of those of the left side, 
except the first three and the seventh, ninth, and eleventh. Of the plastron there is present 
a considerable part of the right hyoplastron and hypoplastron. A number of Wieland's figures 
are here reproduced. 

As to the distinctness of this species from all that have hitherto been described there may be 
doubts, which it is too early to remove. Of two of the described species, T. brachyrhina and 




Fig. 229. — Toxochelys bauri. Carapace of the type. X». 

c. p. I, c. p. 1, c. p. 8, first, second and eighth costal plates; /, fontanels behind nuchal; n. 1, n. 2, etc., the neural 
bones; nu.p, nuchal plate; per. 10, the tenth peripheral; py, pygal bone; spy. i, spy. 2, spy. 3, the 
suprapygal bones. Or, spy. i may be the ninth neural; spy. 2 and spy. 3, first and second suprapygals. 

T. procax, no portions of the shell are known; and T. bauri may be the shell of one of these. 
Of T. latiremis only small portions of the shell are known; but to judge from the figures of the 
nuchal that have been publisht, the species is distinct from T. bauri. The latter appears pretty 
certainly to be distinct from T. stenopora. Of the carapace of T. serrifer Cope there are known 
only two peripherals, apparently the eighth and the ninth. These appear to resemble greatly 
the same peripherals of Wieland's species. They belonged to an individual about half the 
size of the latter. The eighth of Wieland's type had a length of 80 mm. and a width, at the 
notch, of 45 mm.; the ninth, a length of 75 mm. and a width of 45 mm. The eighth oiT . serrifer 
is 41 mm. long and 25 mm. wide; the ninth, 43 mm. long and 27 mm. wide. It will be seen that 



TOXOCHELYID^. 



179 



the latter two peripherals are slightly wider proportionally than are those of T. bauri. As 
regards the thickness no definite statements can be made about either species, but both appear 
to resemble the corresponding peripherals of Lytolomn. 

The carapace of T. bauri has a length of about 530 mm. ; its greatest width, when restored 
to what is regarded as its original form, is about 400 mm. The species was therefore of consid- 
erable size and the form was relatively narrow. In front the outline is concave along the nuchal; 
while the rear is rounded. There are no excavations over the anterior limbs, such as are seen 
in the modern Cheloniidae. 

This carapace is composed of 8 pairs of costals, a nuchal, 9 neurals, apparently 3 suprapy- 
gals, a pygal, and 11 pairs of peripherals. The first, second, and tenth peripherals had no 
connection with the costals. The others received each the extremity of a rib in a pit. In all, 
except the third and the eleventh, this pit is nearest the hinder end of the peripheral. There 
are large costo-peripheral fontanels, which extended from the peripherals half-way to the 
neurals. Besides these vacuities, there is a small one on each side at the common meeting- 
place of the nuchal, the first costal, and the first neural. Similar vacuities are found in a few 
of the Trionychidae. 

The accompanying table shows the dimensions of the neurals, taken from Wieland's 
description of the species. The forms may be determined from fig. 229. 



Neural. 


Length. 


Width. ' 


I 


38 


38 i 


1 


44 


37 


3 


44 


40 


4 


46 


♦+ ( 


5 


34 


+5 i 


6 


50 


40 1 


7 


40 


38 


8 


25 


35 


9 


'S 


35 




Fig. 230. — Toxochelys bauri. Shell presenting left side. Xn. 

/, fontanels behind the nuchal; i, 5, 5, series of ossicles surmounting certain of the 
neural bones. Reproduced from figure by Wieland, 

It seems evident that an extra neural was intercalated in the series. This is shown by the 
fact that, as the series runs, most of them are crowded somewhat out of their natural positions, 
being nearly as much in contact with the costals in front of them as with those to which they 
belong. This intercalation is shown in another way. There is a series of ossicles, 4 in number, 
along the midline — ossicles which Wieland calls epineurals. The first forms a slight boss on 
the first neural. The second lies across the suture between the third and the fourth neurals; 
the third, across the suture between the fifth and the sixth neurals; the fourth rests on the 
eighth and ninth neurals and the first suprapygal. This arrangement does not agree with 
that appearing to exist in the other specimens of this genus which have furnisht the neurals. 
Moreover, it does not correspond with the usual arrangement of the horny scutes of turtles. In 
the specimen described by the writer in the American Naturalist (xxxii, 1898, p. 936) and in 
the specimen here described on page i64,a sulcus passes behind each of the tubercles surmount- 
ing the neurals. This sulcus in each case separates two of the 
vertebral scutes. Now, almost without exception, the first sulcus 
crosses the first neural, the second crosses the third neural, the 
third traverses the fifth neural. The position of the fourth trans- 
verse sulcus varies somewhat, but it is usually found on the eighth 
neural. In the present specimen the sulci must have crost on the 
first, the fourth, the sixth neurals and the first suprapygal. It 
seems evident that it is the third neural of the series that is an 
intruder and disturber. In a specimen of Colpochelys kempi, in 
the American Museum of Natural History, there are all together 
13 neurals. The sulci cross on the first, the fourth, the eighth, 
and the twelfth neurals. 

The nuchal bone has a width of 120 mm. along the free 



Peripheral. 


Length. 


Width. 
»5 




60 




5° 


*5 




59 


28 




60 






65 


28 




70 


33 


7 


75 




8 


80 


45 


9 


75 


45 


10 


70 


45 


II 


68 


45 



l8o FOSSIL TURTLES OF NORTH AMERICA. 

border; a maximum width of 145 mm. Its fore-and-aft extent is 55 mm. The table gives the 
dimensions of the peripherals. The width is taken at the notch of each where the sulcus crost 
the free border. 

On account of considerable crushing the thickness has not been given. We are informed 
by Wieland that transverse sections are approximately as in the peripherals of Lytoloma 
angusta ( = /.. ^vielandi). 

The pygal measures 65 mm. along the free border and 45 mm. along the midline. 

The reader is referred to page 165 for remarks on the connection of the rib of the eighth 
costal plate with the eleventh peripheral of this species. 

Genus CYNOCERCUS Cope. 

A genus based on caudal vertebrae and a medapodial. Caudals procoelous and provided 
with chevrons. The articular cup with a median perpendicular groove or incision. 

Type: Cynocercus incisus Cope. 

This little-known genus is placed in the present family because of the possibility that it is 
identical with Toxochelys. 

Cynocercus incisus Cope. 

Cynocercus incisus, CoPE, Proc. Amer. Philos. See, xil, 1872, p. jo8; Proc. Acad. Nat. Sci. Phila. 1872, 
p. 129; Fifth Ann. Report U. S. Geol. Surv. Mont., etc., 1871 (1872), p. ;?J5; Vert. Cret. Form. 
West, 1875, pp. 96, 260, plate viii, figs. 3-5. — Williston, Univ. Geo). Surv. Kansas, iv, 1898, 
p. 368, fig. 6. — Hay, Pubs. Field Columb. Museum, Zool., i, 1896, p. 106; Bibliog. and Cat. Foss. 
Vert. N. A., 1902, p. 442. 

Cynocercus incisus was based on two caudal vertebrae and a metapodial. These were 
found by Cope in the yellow chalk, probably the Niobrara, near Butte Creek, south of Wallace, 
Kansas. These bones are now in the American Museum of Natural History and have the 
number 1582. It is not known whether the metapodial belongs to the fore or the hinder foot. 

The vertebrae were fully described and figured by Cope as cited above. Williston repro- 
duced a portion of the description and the figures of the vertebrae. The reader is referred to 
these authors. It may be here stated that the length of the centrum of each of these vertebrae 
is 27 mm., a fact showing that the animal must have been of considerable size. They did not 
belong among the most anterior, for they possest chevrons. Cope stated correctly that they 
differ from those of Chelydra in being procoelous. They differ further from those of the latter 
genus in being more comprest and in having higher neural arches. Cope suggested a resem- 
blance to those of the Trionychoidea. From the latter they difl^er in possessing chevrons and 
in having the transverse processes attacht to the centrum. The vertebrae of the anterior half of 
the tail of soft-shelled turtles have high neural arches; from these spring transverse processes. 

What appears to distinguish these caudals from those of any other known genus is the 
presence of a sharp groove, or incision, running perpendicularly down the middle of the articu- 
lar cup. It has been suggested by more than one author that these vertebrae are those of 
some species of Toxochelys; but this has not yet been proved. 

Genus PORTHOCHELYS Williston. 

Skull as broad as long. Nasal bones present. Lateral fontanels of the carapace obsolete. 
All of the peripherals articulating closely with the costals. No carina along the middle of the 
back and no tubercles. Plastron with small median and lateral fontanels. 
Type : Porthochelys laticeps Williston. 

Porthochelys laticeps Williston. 

Plate 31, figs. 2, 3; text-figs. 231-234. 

Porthochelys laticeps, Williston, Trans. Kansas Acad. Sci., xvii, B, 1901, p. 195, plates xviii-xxii. 
Hay, Bull. Amer. Mus. Nat. Hist, xxi, 1905, p. 183. 

The type of this fine species is the property of Kansas University and was collected in the 
Niobrara beds, on the Saline River, in Trego County, Kansas. The remains comprize the 
greater portion of the skull, nearly the whole of the left side of the carapace, the whole of the 



TOXOCHELYID^:. 



iSl 



plastron (except the epiplastia and the entoplastron) and the right humerus. From the portion 
of the carapace present the whole has been restored, as seen in Professor Williston's original 
description. The figures presented in the present work have been redrawn, with slight modi- 
fications, from Williston's paper. 

The skull (figs. 231, 232) is remarkable for its breadth and the massiveness of the jaws. 
As shown by the figures, the posterior breadth is maintained with slight diminution far forward, 
so that the head appears very blunt, altho the snout is somewhat produced. The narial 
opening is broader than high, and its upper boundary is furnisht mostly by a pair of small 
nasals. The orbits are rather large and directed rather strongly upward. The interorbital 
space is 19 mm. wide. The bones covering the temporal region are so much damaged that the 





Figs. 231 and 232. — Porthochelys laticeps. Skull of type. 

251. Upper surface. 232. Palatal surface. 



Xi. 



extent of the roof can not be determined; but it was probably as extensive as in Toxochelys. 
The bones of the upper surface of the skull are much roughened, as in Chelydra. 

The palatal surface of the skull is shown in fig. 232. The cutting-edge of the maxilla is 
deeper than in Toxochelys latiremis, and its depth increases toward the jugal bone. The palatal 
surface of the bone, 10 mm. wide in front, increases to 20 mm. at the hinder end. The masti- 
catory surface extends over on the palatine and is markt internally by a rough ridge. Trans- 
versely the surface is slightly concave. The choanae are not encroached on by plates from the 
vomer and palatines, as they are in the Cheloniidae, but lie well forward in a shallow fossa. 
They are separated by the vomer, which is wide anteriorly, narrow between the choanae, and 
develops a sharp ridge on its palatal surface. As in Chelydra, each pterygoid developt a strong 

lateral process, against which the mner surface of the 
dentary workt. The width of the pterygoids, where 
narrowest, is 30 mm. The quadrates are notcht behind 
for the passage of the columella, as in Toxochelys. 

Of the mandibles only the united dentaries are pres- 
ent (fig. 233). They are very heavy and strong bones. 
The masticatory surface is somewhat concave both trans- 
versely and longitudinally, and is bounded internally 
along the anterior half by a rough ridge. At the sym- 
physis the two ridges unite and run to the front of the 
jaw. This masticatory surface is, in front, only about 
half as wide as is the symphysis itself; but it widens 
backward and overhangs the inner lower border of the 
jaw. The coronoid process is considerably elevated, 
ipace (plate 31, fig. 2; text-fig. 234) is now very flat. How deprest it was during 
ossible now to say; but it probably had no great elevation. It is nearly circular, 




Fig. 233. — Porthochelys laticeps. Den- 
tary bones of type. Xi- Redrawn 
from Williston's figure. Showsgrind- 
ing-surfaces. 



The carap 
life it is impossible now to say; 



1 82 



FOSSIL TURTLES OF NORTH AMERICA. 



the width being 785 mm., the length only 730 mm. The border appears to have been slightly 
excavated in front, elsewhere somewhat repand. The costal plates are so extensively ossified 
that there now remain only insignificant fontanels at their outer ends. The greater portion of 
the nuchal bone is missing. The peripherals are eleven in number on each side. They are 
rather narrow in front but their width increases posteriorly, and they become quite thick. 
The sixth from the front is equal in width to one-eighth of the width of the carapace; the eighth 
is a little more than one-sixth of the width of the carapace. 

Of the neurals the fifth and sixth are wholly wanting, while the fourth and seventh are 
represented each by only a small portion. Those present are narrow, about 30 mm. wide. The 

second, third, and fourth have their anterior outer angles 
cut off by contact with the costals in advance. The 
neurals are smooth, and without trace of the tubercles 
which are so conspicuous in Toxochelys. There are two 
suprapygals, each forming a symmetrical trapezoid, and 
these are placed base to base. 

Dermal scutes were present, and are indicated by very 
distinctly markt sulci. The vertebrals are narrow, the 
third and fourth being about one-seventh as wide as the 
shell. The first is slightly wider; the fifth has a width 
equal to one-fourth the width of the shell. The mar- 
ginal scutes lie almost wholly on the peripheral bones. 
The plastron (plate 31, fig. 3) resembles greatly that 
of Toxochelys. There were small central and lateral 
fontanels. Probably the right and left halves of the 
plastron approacht each other more closely than is 
shown in the figure. The thickness of the hyoplastron 
and hypoplastron where they join is from 10 to 12 mm. 
They are thin and serrated along the median border. 
The right humerus accompanies the remains, but the 
ulnar process is broken away. The bone is flattened, 
mostly as a result of compression during burial. It 
appears to have resembled closely the corresponding bone 
oi Toxochelys; but the radial process has been directed 
more strongly toward the ulnar side. The total length of 
the bone was 140 mm. The position and extent of the 
epicondylar groove and of the condyles for the radius and ulna seem to have been the same as 
in Toxochelys. Two cervical vertebrae, a small portion of the scapula, and a claw are mentioned 
by Williston as furnishing no important differences when compared with those of Toxochelys. 
In general appearance this turtle differs greatly from Toxochelys. The head is of heavier 
construction and of blunter form; there are nasals; the carapace is circular, instead of 
elongated and pointed behind; it is more extensively ossified; and there is no carina along the 
middle of the back. Otherwise Porthochelys agrees with Toxochelys. As already remarkt, 
the presence of nasals is regarded as being of no more than generic value. 

Porthochelys browni Hay. 
Figs. 235-237. 
Porthochelys browni, Hay, Bull. Amer. Mus. Nat. Hist, xxi, 1905, p. 183, figs. 15, 16. 

The type of this species was collected during the summer of 1903, by Mr. Barnum Brown 
of the American Museum of Natural History, in deposits shown by their invertebrate fossils 
to belong to the Pierre formation. The locality is 20 miles southeast of Edgemont, South 
Dakota. The catalog number of the specimen is 6080. 

The specimen presents the skull and the lower jaw nearly complete, some pelvic bones, 
one humerus, one scapula, a femur, and some other limb bones. Unfortunately most of the 
bones are crusht nearly flat and were covered with a layer of gypsum. Altho the skull is consid- 
erably crusht, the most essential elements of its construction may be determined. 




Fig. 234. — Porthochelys laticeps. Cara- 
pace of type. X i. Restored por- 
tions indicated by dotted lines. 



TOXOCHELYID^,. 



183 



The skull is broad and it was probably originally considerably deprest, but to what extent 
the present flatness is due to pressure can not be determined. The outlines as seen from above 
(%• 235) are greatly like those of Porthochelys laticeps, but the skull of the present species 
is longer than broad. The sides of the skull converge slowly to the front of the orbits, where the 
width is still 100 mm., then rapidly approach the tip of the snout. The outline is such that the 
snout appears somewhat produced. The occipital condyle is broken away, but from its esti- 
mated position to the end of the snout is 160 mm.; from the end of the supraoccipital spine to 
the snout, 190 mm. The breadth from the outside of one quadrate to that of the other is 142 
mm. The bones of the upper surface of the skull are smooth, whereas those of P. laticeps are 
ridged and grooved. The temporal region is rooft over not quite as far backward as the 
hinder borders of the exoccipitals and paroccipitals, so that the latter bones are seen from above. 
Hence, the roof is not so extensive as in Chehnia mydas, but about as complete as in Carettn. 




Fig. 235. — Porthochelys browni. Skull of type, upper aspect, xi. No. 6080 A. M. N. H. 
fr, frontal; ju, jugal; mx, maxilla; pa, parietal; pof, postfrontal; />rf, prefrontal; sq, squamosal. 

The eyes of this turtle were evidently directed strongly upward as well as outward. The 
distance from the middle of the lower part of the rim of one orbit to that lof the other is 90 mm. 
The width of the interorbital space is 30 mm. If now the middle of the interorbital space 
stood 50 mm. above the roof of the mouth the plane of the orbits would stand at an angle of 
45° with the horizontal. It is not probable that the elevation of the skull was greater than that 
supposed. The longitudinal diameter of the orbit is 50 mm. The transverse diameter of one 
is now 33 mm., of the other 30 mm. If the elevation of the skull was originally 50 mm. above 
the roof of the mouth the transverse diameter of the orbit must have been about 43 mm. It 
is not likely to have been more. Hence, we seem to be justified in believing that the eyes were 
directed strongly upward. 

It is evident that the nasal opening was higher than wide. Its present width is 19 mm., its 
height 21 mm. The distance from the orbit to the hinder border of the temporal roof is 53 mm. 

The anterior borders of the choanae are placed 43 mm. behind the tip of the snout (fig. 236). 
The palatines appear to have joined the vomer, as in Toxochelys. The crushing-surfaces of 
the upper jaws have a width of about 27 mm. They are concave from the cutting-edge of the 
jaw to the palatines. The width of the combined pterygoids, where narrowest, is 39 mm. 



184 



FOSSIL TURTLES OF NORTH AMFRICA. 



The lower jaw (fig. 237) is nearly complete. The crushing-surface has a width of 18 mm. 
and is convex transversely. The cutting-edge is acute and directed outward, possibly due 
partly to distortion. The tip of the jaw appears to have been somewhat upturned as a beak, 
and there is a corresponding pit in the upper jaw just behind the premaxillae. The symphysis 
has a length of 35 mm. 

The humerus is crusht very flat and the ulnar process is broken off. The length of the bone, 
measured from the proximal surface of the head to the distal end, is 156 mm. The impression 




Figs. 256 AfiD z^J.-Porthochelys hrowni. 
Skull and lower jaw of type. Xj. 

236. Palatal surface, m.v, maxilla; palf palatine; 
pt, pterygoid; qUj quadrate; z?om, vomer. 

237. Lower jaw. ang^ angular; art, articular; 
dartf dermarticular; den, dentary; sur, 
supraangular. 

of nearly the whole head appears on the upper side of the flattened bone; hence it is evident 
that the head was directed upward when the bone was horizontal and not as it is in the 
Cheloniidae. The radial process was connected with the head and there existed a broad exca- 
vation, or fossa, between this process and the ulnar process. In short, the humerus appears 
to have had practically the form of that of Chelydra. 

The distal end of the femur is missing, but the bone was at least nearly as long as the 
humerus. It was, however, a slenderer bone. 

The ilium resembles closely that of Toxochelys. 

Family DESMATOCHELYIDyE Williston. 

Skull with temporal region rooft over as far backward as the occipital condyle. Large 
nasal bones present. Choanae placed well foi-ward, not underfloored by the vomer, maxillae, 
and palatines. Small posterior palatine foramina present. Humerus indicating a paddle-like 
fore limb. Plastron loosely joined to the carapace. 

The type of this family is the genus Desmatochelys, but the genera Atlantochelys and 
Neptunochelys are provisionally included. The two latter are known only from humeri. 
These are not greatly different from the same bones in the Cheloniidae. 

Genus DESMATOCHELYS Williston. 

Desmatochelys, WiLLlSTON, Kansas Univ. Quart., in, 1894, p. 5. 
Desmochelys, BouLENGER, Zool. Record, Reptiles, 1895, p. 29. 

The generic characters are not yet to be distinguisht from those of the family. 
The type of the genus is Desmatochelys lowi Williston. 



DESMATOCHELYIDiE. 



185 



This genus is a most interesting one, inasmuch as it shows evident relationships with the 
Cheloniidae, and at the same time presents characters which must be regarded as more primitive 
than those of the latter family. Among these characters is the possession of well-developt 
nasal bones. The choanae too have their primitive position just behind the premaxillae and are 
separated by the body of the vomer. In the Cheloniidae the latter bone sends downward a 
perpendicular plate, the lower border of which expands laterally and joins horizontal plates 
of the maxillae and of the palatines, forming a floor beneath the narial passages and pushing 
the choanae further backward. The possession of small posterior palatine foramina shows a 
closer connection with Amphichelydian stock than exists in the Cheloniidae, which have lost 
these foramina. 

Williston thinks that the cervical vertebrae indicate pleurodiran characters. The posses- 
sion of strongly developt transverse processes is to be regarded as an inheritance rather trom 
the Amphichelydia than from the Pleurodira. The articular ends of the cervical vertebrae 
show decided aflinities with the Cryptodira. An intervertebral articulation which is 26 mm. 
wide and only 15 mm. high, belonging to a centrum only 26 mm. long, would not lend itself 
readily to flexure sidewise, while it would permit easy flexure in a perpendicular plane. 

The Desmatochelyidae are to be arranged close to the Cheloniidae; but their many prim- 
itive characters demand that they be kept in a distinct family. For those who are seeking a 
Cretaceous ancestor for the modern sea-turtles, Desmatochelys presents itself as a more eligible 
form than any of the Cretaceous Thalassemydidae. 





Figs. 238 and 239. — Desmatochelys lowi. Skull of type. Xj. 
238. Upper surface. 239. Seen from below. 



Desmatochelys lowi Williston. 

Figs. 238-243. 

Desmatochelys lowii, Williston, Kansas Univ. Quart., ill, 1894, p. 5; Univ. of Kansas Geol. Surv., 
IV, 1898, p. 353, plates Ixxiii-ixxviii. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 443. 

The original and only known materials belonging to the present species are the property 
of the University of Kansas. They consist of the skull, finely preserved, but lacking the hinder 
part of the base; 3 cervical, the sacral, and some caudal vertebrae; the pectoral girdle, the 
humerus, radius, and some metacarpal bones; most of the pelvic bones and an incomplete 
femur; some fragments of the carapace and some of the plastron. The animal was apparently 
preserved in fine condition, but was damaged in collecting. The remains were found in Benton 



1 86 



KOSSIL TURTLES OF NORTH AMKRICA. 



deposits, near Fairbury, Nebraska. An extended description of the species, with figures, is 
given by Williston, as cited above. A number of his drawings have been reproduced in the 
present work. 

This turtle was evidently a large one. The skull (figs. 238, 239) is uncrusht, but the hinder 
portion of the base is damaged. The total length from the snout to the end of the supraoc- 
cipital spine is 205 mm.; the width thru the quadrates is 145 mm. The skull is remarkable 
for the length of the posterior lateral, or squamosal, processes. These lack but little of extend- 
ing backward as far as the supraoccipital process; while the latter has about its usual length. 
The parietals are unusually narrow. Williston informs us that these bones join the squamosals. 
The frontals and the prefrontals together occupy the area occupied in Chelonia mydns by the 
frontals. In front of the prefrontals come the large nasals, bones rarely found in Cryptodira. 
These nasals are about 13 mm. long and each is about 19 mm. wide. The antero-posterior 




Figs. 240-243. — Desmatochelys lowi. Portions of the type. Xj. 



240. Humerus. 

241. Pelvic bones. //, ilium; ijc/t, ischium; puhj pubis. 



242. Fragments of peripheral bones. 

243. Fragments of plastron and peripheral bones. 



diameter of the nasal opening is 24 mm.; the transverse diameter, 18 mm. It looks strongly 
upward. The orbits have an antero-posterior diameter of 60 mm. The interorbital space is 
58 mm. wide. 

The palate (fig. 239) is remarkable on several accounts. The choanae are considerably 
further forward than they are in the Cheloniidae; but what is more important, there is no floor 
beneath them formed by the bones bounding them. Each is at the anterior end of a longitudinal 
concavity, whose depth diminishes backward. The transverse sutures between the palatmes 
and the pterygoids are relatively much further backward than they are in Chelonia mydas. 
The pterygoid processes are therefore more posterior than usual. The possession of posterior 
palatine foramina is another feature distinguishing this species from any of the modern sea- 
turtles. They are small, and may be regarded as vestigial. Behind the pterygoid processes 
the palate narrows to a width of about 22 mm. In front of the processes named there is another 
slight constriction of the palate. The longitudinal median sutures are not discernible, and it 
is not certain that the palatines joined in the midline. 



DESMATOCHELYID^. iS/ 

The lower jaw is firmly cemented to the skull, hence no examination can be made of the 
triturating surfaces; they were, however, undoubtedly narrow. The symphysis is 43 mm. long. 

Williston has described and figured one cervical vertebra. It is 26 mm. long, a fact indi- 
cating that the neck was short. The articular surface is 26 mm. from side to side and 15 mm. 
vertically. Near the hinder end of the centrum there is, on each side, a stout transverse process. 

The sacral and several caudal vertebrx are preserved and have been described by Williston. 
The caudals are all small and procoelous. 

The length of the scapula, measured from the tip to the lower border of the proscapular 
process, is 158 mm. The process just named is 82 mm. long. The coracoid has a length of 
100 mm. and a width, at the free end, of 35 mm. The shaft is much constricted in the middle 
of the length. 

The humerus (fig. 240) is a large flat bone, which, by its whole structure, shows that it 
belonged to a turtle which dared the open seas. The length, from the proximal surface of the 
head to the distal end, is 202 mm.; while the extreme length is 260 mm. The last dimension 
indicates the great height of the ulnar process. The width across the head and the ulnar 
process is about 1 10 mm. The shaft, where narrowest, has a diameter of 80 mm. The distal 
end is rounded and has a width of 80 mm. The radial process is large and extends downward 
on the shaft about 90 mm. below the upper surface of the head. 

Williston figures a radius, a supposed ulna, and various bones belonging to the hand. 
Fig. 241, from Williston, represents the ilium, ischium, and pubis of the right side. Williston 
figures also an incomplete femur. Evidently it was a feebler bone than the humerus. 

But littleof the carapace was secured. The costal plates have a thickness of only 2 or 3 mm. 
The rib-heads are stout. One of the hinder costals has a width, near the proximal end, of 
40 mm. The neural corresponding to it is 32 mm. wide. No sulci have been observed on any 
of the bones of the carapace. 

Fig. 242, from Williston, represents the pygal and the adjoining right peripheral. The 
pygal measures antero-posteriorly at the midline, 61 mm.; and from side to side, 97 mm. 
Its thickness is 6 mm. 

Fig. 243 represents a fragment of one of the plastral bones and one of the lateral peripherals. 
Evidently, the plastral bones were loosely connected with the carapace, as in the Cheloniidae. 
The peripheral has a length of 130 mm., and a width of about 35 mm., and a thickness of 6 mm. 
Other peripherals, believed to be more anterior in position, are thicker and longer. 

Not enough of the plastron was secured to furnish exact knowledge regarding its structure. 

Genus NEPTUNOCHELYS Wieland. 

A genus based wholly on a humerus of a turtle which was adapted for life on the sea. 
Humerus flattened; the head, the ulnar, and the radial processes in the plane of flattening, or 
nearly so. Radial process not so far removed from the head as in the Protostegidae. Humerus 
resembling that of the Cheloniidae, still more that of Desmatochelys, differing from the latter 
in having the head more nearly in the axis of the bone and the ulnar process nearly parallel 
with the axis. 

Type: Neptunochelys tuberosa (Cope). 

Neptunochelys tuberosa (Cope). 

Fig. 244. 

?Holcodus acutidens, Leidy, Smithson. Contrib. Knowl., xiv, art. vi, 1865, pp. 42, 118, plate viii, figs. I, 2. 
Protostega tuberosa, CoPE, Fifth Ann. Report U.S. Geol. Surv., Montana, etc., 1871 (1872), p. 334; Vert. 

Cret. Form. West, 1875, p. 257. 
Atlantochelys tuberosus, Leidy, Ext. Vert. Fauna West. Terrs., 1872, p. 342. 
Neptunochelys tuberosa, Wieland, Amer. Jour. Sci. (4), IX, 1900, pp. 417, 418. — Hay, Bibliog. and 

Cat. Foss. Vert. N. A., 1902, p. 440. 

No part of this great sea-turtle is known except the humerus. This was found many 
years ago by Dr. Spillman, in Upper Cretaceous deposits, at Columbus, Mississippi. Having 
been found associated with the bones of a mosasauroid reptile and described before the limbs of 
the Mosasauria were known, it was believed to be possibly the humerus of HolcoJus acutidens. 



i88 



FOSSIL TURTLES OF NORTH AMKRICA. 



Cope was the first to refer the hone to the turtles, and he placed it in his genus Protostega. 
At a little later time Leidy referred it to Atlantochelys. In 1889 Baur correctly concluded 
that it could belong to neither Protostega nor to Atlantochelys, but he did not name the genus. 
This was reserved for Wieland to do in 1900. 

The total length of the humerus (fig. 244) is 10 inches, or 253 mm. The shaft, where 
narrowest, is 48 mm. wide and 28 mm. thick. The distance from the extremity ot the ulnar 
process to that of the radial process was estimated to be 152 mm. The breadth ot the distal 
end is 93 mm.; the thickness, 30 mm. The form of the bone is shown by the figure, copied 
from Leidy. 

Genus ATLANTOCHELYS Agassiz. 

A genus based on the proximal end of a humerus of a sea-turtle. The head and the ulnar 
and radial processes in approximately the same plane. Radial process hardly separated from 
the head. Ulnar process directed nearly parallel with axis of bone. Shaft unusually slender. 

Type: Atlantochelys mortem Agassiz. 





Fig. 244. — Neptunochelys tuherosa. 
Humerus forming the type. Xj. 



Fig, 



245. — Atlantochelys mortoni. Portion of humerus 
forming the type. X § ± . After Leidy. 



Atlantochelys mortoni Agassiz. 
Fig. 245. 

Atlantochelys mortoni, Agassiz, Proc. Acad. Nat. Sci. Phila. 1849, p. 169 (no description); in Leidy, 
Smithson. Contrib. Knowl., xiv, art. vi, 1865, p. 43. — Leidy, Ext. Vert. Fauna West. Terrs., 
1872, p. 342. — Wieland, Amer. Jour. Sci. (4), 1900, p. 419, figs. 14-16. — Hay, Amer. Naturalist, 
XXXII, 1898, p. 930; Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 440. 

Mosasaurus mitchelli, Leidy, Smithson. Contrib. Knowl., xiv, art. vi, 1865, 43, 117, plate viii, figs. 3-5. 

Protostega neptunia. Cope, Fifth Ann. Report U. S. Geol. Surv. Terrs., 1871 (1872), p. 334; Proc. Amer. 
Philos. Soc, XII, 1872, p. 433; Vert. Cret. Form. West, 1875, p. 257. 

Like Neptunochelys tuherosa, this species is based on a humerus which was derived from 
the Upper Cretaceous formation. The exact locality and level were not reported, but we 
know that the fossil was found in one of the beds of Cretaceous greensand in Burlington 
County, New Jersey. 

Of this humerus (fig. 245) there was secured only the proximal half or less. This fragment 
had a length of about 280 mm. The shaft was extremely slender, being 73 mm. wide and 
60 mm. thick. The ulnar process rises above the head about 75 mm. The radial process is 



DESMATOCHELYID^. 



189 



hardly separated from the head. The ulnar process is nearly parallel with the long axis of the 
bone. The head is farther removed from the axis than in Neptunochelys. In these two 
respects Atlantochelys resembles Desmatochelys; but it differs from the latter in having a 
slender shaft. This humerus must have been fully as long as that of Archelon, but it was of 
very different form. A very large turtle is indicated. 

Family PROTOSTEGIDiE Cope. 

Marine turtles with the fore limbs converted into flippers resembling those of the Che- 
loniidae. Carapace greatly reduced, the disk extending not one-half the distance toward the 
distal ends of the ribs. Peripherals present. Plastron loosely connected with the carapace 
and with a large median fontanel. Entoplastron T-shaped, with the lateral wings elongated 
and distally expanded. Epiplastra not certainly known. Xiphiplastra short and bent. Skull 
large, temporal region broadly rooft over. Region in front of the orbits elongated. Jaws with 
large crushing-surfaces. Choanae far forward; not underfloored by the surrounding bones. 

Genera: Protostega, Archelon, and probably Protosphargis, all of the Upper Cretaceous. 

The writer is strongly of the opinion that the genera Protostega and Archelon ought to be 
kept apart from the modern sea-turtles as a distinct family. That both the Protostegidae 





Fig. 246. — Protostegfi potens. Entoplastron and xiphiplastron of type. X i. 
ent, entoplastron; xiph, xiphiplastron. 

and the Cheloniidae had their origin from a common ancestor, which was a sea-going turtle, 
need not be denied; but the two branches have been separated so long, and each has developt 
so many peculiarities, that it seems unwise to force them into the same family. That the 
Cheloniidae have been derived directly from the Protostegidae it is impossible to believe. The 
latter family was in several respects more highly differentiated than the living sea-turtles. 
The greatly reduced carapace, the peculiar entoplastron, the abbreviated xiphiplastra, the 
large preorbital region, and the strongly modified humeri are examples of these differentiations. 

For the discussion of the relationships of this family to the Cheloniidae and to the Der- 
mochelyidse, the reader is referred to the papers of Baur, Case, Fiirbringer, Van Bemmelen, 
Boulenger, Lydekker, Dollo, Wieland, and Hay. 

The bone which is here regarded as the entoplastron (fig. 246, ent) was, in Protostega, 
originally described by the present writer, on the advice of Dr. Baur, as the nuchal. This 
view was adopted by Case and afterwards by Wieland.* The latter, in describing Archelon, 
originally held the bone to be the coalesct epiplastra and entoplastron, called by him the 
paraplastron. A re-examination of the subject, in the light of all the known materials, has 
led the present writer to change his opinion. The reasons for regarding this bone as the 
entoplastron are the following: 

(i) The bone has never been found in direct connection with peripheral bones. 

(2) It has been found four times closely associated with plastral bones, and in two or 
three of these cases it was in its apparently natural position with relation to the hyoplastra. 

♦Since this was sent to the press Dr. Wieland has publisht a paper (Ann. Carnegie Mus., iv, 1906, 
p. 8) in which he accepts the view that the bone is the entoplastron. 



lyO FOSSIL TURTLES OF NORTH AMERICA. 

In the first instance it accompanied only plastral bones that were described by the writer. 
Then Case found it with its lateral wings resting on the hyoplastra. He supposed that it 
had fallen from the carapace to its position, a not unreasonable conclusion. After this 
Wieland informed us that he had found it twice in place, resting directly upon the anterior 
portions of the hyoplastra and beneath numerous other skeletal parts. 

(3) Wieland described a bone as the nuchal which can hardly be anything else. 

(4) In the specimen described here as P. potens the bone in question again occurs. On 
the visceral surface, near the anterior border, there is, on each side, a deep and broad groove 
(fig. 246) that must have received another bone. This groove reaches nearly to the midline. 
It is quite improbable that the first peripheral had a long process that filled this groove. On 
the other hand, the epiplastron might be expected to lie on the upper side of the entoplastron. 
The structure of this entoplastron is not far distant from that of Chelydra. In this genus 
there is a median backwardly directed process from the anterior end of which, on each side, 
there projects a lateral slender process. Were these lateral processes to become directed 
at right angles with the median process and to become broader, we would have just such an 
entoplastron as we have in Protostega. In Chelydra, Chelonia, and Caretia we find that 
the epiplastra overlap the lateral processes of the entoplastron, just as they seem to have 
done in Archelon and Protostega. 

As regards the superposition of the T-shaped bone on the hyoplastra of Protostega there is 
this to be said. The entoplastron appears naturally to join the hyoplastra edge to edge. Often, 
perhaps usually, the hyoplastra push themselves slightly over the entoplastron anteriorly. 
It is, however, certain that the posterior spine-like prolongation falls above the hyoplastra. 
If the entoplastron expanded laterally without suturally joining the hyoplastra, there appears 
to be no reason why it should not rather pass above than below the latter bones. The epiplastra 
are missing in all the specimens in which the T-shaped bone accompanies plastral bones. 
These were, however, probably thin, light bones and could easily be removed from their 
natural position. Their outer ends, doubtless, were in ligamentous union with the anterior 
borders of the hyoplastra. 

In Wieland's paper just referred to he describes a bone of Archelon which he regards 
as the left epiplastron. He holds that this bone was overlapt by the outer end of the T- 
shaped entoplastron, that certain grooves in the bone were filled by digitations or ridges of 
the entoplastron, and that the thickened anterior end of the bone projected outward and 
forward as in the trionychids. The present writer finds it impossible to place the bone in 
this position. It seems more probable that the bone is the right epiplastron, that the thinner 
end narrowed to a point and was directed inward on the upper surface of the wing of the 
entoplastron, while the thickened end was directed backward along the border of the hyo- 
plastron. 

Genus PROTOSTEGA Cope. 

Premaxillary beak less developt than in Archelon. Maxilla with a rather broad grinding- 
surface, which extends backward to behind front of orbit. Lower jaw with the rami early 
co-ossified. Entoplastron T-shaped, with the middle third of the anterior border concave 
from side to side, the distal ends convex. Radial process of humerus large. 

Type: Protostega gigas Cope. 

Protostega gigas Cope. 

Figs. 247-253. 

Protostega gigas, CoPE, Proc. Amer. Philos. See, Xll, 1871, pp. 175, 452; Fifth Ann. Report U.S. Geo!. 

Surv. Montana, etc., 1871 (1872), pp. 323, 335; Vert. Cret. Form. West, 1875, pp. 48, 102, 256, 

plate ix, figs. 1-7; plates x-xiii; Amer. Naturalist, xil, 1878, p. 137.- — Hay, Pubs. Field Columb. 

Mus., Zool., 1, 1895, p. 57, plate iv, v; Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 440. — Case, Jour. 

Morphology, xiv, 1897, p. 21, plates v-vi. — Wieland, Amer. Jour. Sci. (4), ix, 1900, pp. 416, 420, 

figs. 8, 19; Mem. Carnegie Mus., 11, 1906, p. 279, plates xxxi-xxxiii, text-fig. I. — WlLLISTON, Amer. 

Jour. Sci. (4), XIII, 1902, p. 276, fig. I. — OsBORN, Science, xix, 1904, p. 35. — Sternberg, Trans. 

Kansas Acad. Sci., xix, 1905, p. 123. 
Atlantochelys gigas, Dana, Manual Geol., ed. 11, 1875, p. 466. 



PROTOSTEGID^. 



191 



The specimen of this species which Cope originally described was found by him in 1871, 
in Niobrara deposits, near Butte Creek, south of Wallace, Kansas. This is now in the Ameri- 
can Museum of Natural History and has the number 1503. At the time of its discovery the 
bones were much distorted and comprest; and most of them were much fractured in collecting 
them. Cope states that the portions described by him were reconstructed out of over 800 
pieces. One of the large bony plates, described as overlying the ribs, had been broken into 
108 pieces. Most of the bones are yet in the condition in which Cope left them; the large 
plates are, to a great extent, again broken up. 

As stated by Cope, the remains preserved include many parts of the skull; 5 vertebrx, 
more or less incomplete; the scapular arches of both sides, with the coracoids; both humeri 
perfect, and some phalanges; 10 ribs; i doubtful neural bone; 10 peripherals; parts of 4 
large plates, described as overlying the ribs; and some undetermined bones. 

From his study of his materials Cope arrived at the conclusion that Protostega was a 
large marine-turtle closely allied to Dermochelys, and had a total length of about 12 feet. 

The first author who added to the knowledge of the species was Dr. George Baur, who 
(Zool. Anzeiger, ix, 1886, p. 688), regarding the genus as Atlantochelys, stated that the plates 
assigned by Cope to the dorsal region were really portions of the plastron. This determination 
was undoubtedly made from the bones collected by Cope. Hay, as cited, gave, in 1897, a 




Fig. 247. — Protostega gigas. Skull of type 



Cope's determinations of the bones within parentheses, ju (pt), jugal, Cope's pterygoid ; m.v (por), inaiilla, 
called by Cope the postorbital; prf, prefrontal; pof, postfrontal; quj (col), quadratojugal, Cope's columella; 
sj (mx), squamosal, called by Cope maxilla. 

description, with figures, of the hyoplastra and hypoplastra of a specimen that had been 
collected for him near Butte Creek, Kansas. Case (1897, as cited) described portions of the 
skull and a more complete plastron than had previously been secured, materials now in the 
University of Kansas; and made correction of Hay's restoration of the xiphiplastra. More 
recently Wieland has described excellent materials which belong to the Carnegie Museum, 
at Pittsburg. 

Cope had considerable portions of the skull and most of these he figured. The writer 
has studied these bones and has found that in most cases Cope's determinations were incorrect. 
Baur had also examined these cranial bones and accepted Cope's determinations (Amer. 
Naturalist, xxiv, 1890, p. 532). 

Fig. 247 represents these bones, each having its name indicated. Cope's determinations 
are indicated in parentheses. 

The first of these elements that will be noticed is that which Cope called the postfrontal 
(Vert. Cret. Form. West, plate xi, figs. 30, 3*). In his description he called this the left post- 
frontal; but, since the straight margin was regarded as the lower, the bone would have to be 
placed on the right side. In reality, the bone is the left maxilla (fig. 247, mx), joined to the 
prefrontal. The straight border is the cutting-border of the maxilla; and the crusht tritu- 
rating surface is seen, in Cope's figure, pushed below this border. Evidently the cuttmg- 



192 



FOSSIL TURTLES OP" NORTH AMERICA. 



edge did not extend much below the triturating surface during Hfe. We can not now tell 
how wide the triturating surface was originally. At its anterior end is seen a broad articular 
surface for the vomer. Cope thought that this surface was for the "zygomatic" bone. Cope 
did not recognize the suture between the lower and the upper portions of the mass of bone 
figured by him. The suture is not distinct, but the radiations on the surfaces of the bones 
show distinctly where the suture is located. The upper bone is the prefrontal, prf. On the 
inner side of its upper border is a broad articular surface for union partly with its fellow bone, 
partly with the frontal. Posteriorly the prefrontal articulated with the postfrontal, pof, thus 
excluding the frontal from the orbit. In Cope's fig. ^a is seen a bridge of bone joining the 
prefrontal with the maxilla. The upper part of this bridge is undoubtedly the descending 
plate of the prefrontal which joined the vomer; the lower portion of the bridge is quite certainly 
a portion of the palatine. The foramen between the bridge and the maxilla is the nasopalatine. 
Cope did not explain the presence of such a bridge of bone on the supposed postfrontal. 

The bones described by Cope as the pterygoid and the columellar, and accepted as such 
by Baur, are the jugal, ju, and the quadratojugal, quj. Those of the right side are shown in 
Cope's fig. 5, plate x; those of the left side in his fig. i, plate xi. What Cope regarded as the 
posterior end of the larger bone is the anterior. The more concave border formed a part of 
the rim of the orbit. The form of both these bones is almost exactly as in Archelon ischyros, 
as figured by Wieland. As in that species, the jugal extended backward to the quadrate. 
The hinder border of the quadratojugal is concave to form the anterior boundary of the 
tympanic cavity. ' It is to be noted that the conspicuous oval mark shown in Cope's fig. i, 
plate xi, is nothing but a little matrix overlaid by a thin layer of bone, probably of some fish. 
In Cope's fig. 5, plate x, the quadratojugal is in nearly its natural position. It is there recog- 
nized as the zygomatic (quadratojugal), but it is the fellow of the bone which on the other 
side is determined as the pterygoid. The other bone, the jugal, has been turned end about, 
to agree with Cope's idea of its proper position. 

Both quadrate bones are present; and that of the right side is represented in Cope's 
fig. 5, plate X. Both are badly crusht, but that of the right side shows the condyle less distorted. 
Just above the condyle, on the outside of the bone, is a scar where the quadratojugal articu- 
lated with the quadrate. On the inner border of the latter bone is another articular surface for 
the hinder end of the pterygoid. 

Cope's fig. 2, plate xi, represents a bone which he identifies doubtfully with the anterior end 
ot the pterygoid. It is really nearly the whole of the pterygoid, a small portion of the anterior 
end alone being broken away. Cope's figure represents the bone as seen from below. At the 
hinder end of the bone, on its upper surface, is a large rough surface for articulation with the 
quadrate. From this extends forward a ridge which may have joined anteriorly either the 
columellar bone of the lower end or the descending process of the parietal. At the hinder end 
and below, and represented in Cope's figure, is a rough excavation for the border of the basioc- 
cipital. The mesial half of the middle third of the lower surface is occupied by a rough surface 
which was overlapt by the basisphenoid. The relations here appear to have been much as in 
Dermochelys. The pterygoids are relatively narrow, outer borders thickened and obtuse. 

The bone identified by Cope as the maxilla (fig. 247, sq) is the squamosal. Cope represents 
that of the left side. He regarded the curved border above the elongated process as the border 
of the orbit and states that the width of the bone below the orbit was 35 mm. Fortunately, the 
corresponding bone of the other side is present; and this shows that that curved border is the 
result of damage to the bone. The upper edge of the bone should extend above the lower 
border at least 90 mm. What Cope took to be the cutting-edge of the maxilla is the free, 
sharp, and smooth hinder border of the squamosal, ascending toward the parietal. What 
Cope regards as the premaxillary border is a free border descending to the quadrate. The wing 
of bone seen extending upward in Cope's figures is the horizontal plate of the squamosal which 
overlapt the upper end of the quadrate and the outer end of the paroccipital. Pressure has 
caused it to lie nearly parallel with the body of the bone. On the outer border, that opposite 
the long, straight border, is seen a portion of the tympanic cavity. Wieland's figure of the skull 
of this species shows that a process of the squamosal reaches the outer border of the parietal. 

The true postfrontal bone (fig. 247, pof) is present, but it was not figured by Cope and 
appears not to have been mentioned. It has on its lower border a process which articulates 



protostegidj*:. 



193 



with the upper border of the jugal. The hinder end of the bone is broken away, so that the 
whole length can not be determined. The breadth of the bone, taken just behind the process 
mentioned, is 105 mm. 

No other parts of the palatines appear to have been preserved than that already mentioned. 
No parts of the premaxillae, nor vomer, nor parietals, nor supraoccipital appear to have been 
obtained with the bones above described. 

Portions of the skull of this species were described by Case as cited in the synonymy. 
The supraoccipital is stated to resemble closely that of the Cheloniidae, and to be quite different 
from that of Dermochelys. The basioccipital resembles that of the latter species, except that 
the portion belonging in the condyle is well ossified. The basisphenoid is said to resemble that 
oi Dermochelys, but is not so large. Case pointed out that the hinder end of the pterygoid was, 
as in Dermochelys, separated from the exoccipital by a lateral process of the basioccipital. The 
imperfectly preserved palatines indicated that the choanae were placed far forward. The vomer 
had no descending process to assist in underflooring the nasal passages. The quadratojugal 
and the squamosal were found to be as in the Cope_specimen, but to the present writer it 

pmxTL — ^ — r~^ mx, ...... /!^ TQd 




Fig. 248. — Proiostega gigas. Skull, limb bones, and front of carapace. Xi. 
No. 1421 Carnegie Museum, Pittsburg. 

Skull, /r, frontal; y'u, jugal; mj:, maiilla ; nor, nares ; ori, border of orbit ; ;ia, parietal ; />r/, prefrontal ; pmx, 

premaiilla; pof, postfrontal; ?a, quadrate; qj, quadratojugal; sq, squamosal. 
Lower jaw. ang, angular; dart, dermarticular, or prearticular; den, dentary; hy, hyoid; jar, supraangular. 
Carapace, nu.p, part of nuchal; per. i, per. 2, first and second peripherals; r. i, second rib. 
Fore limb, c, centrale; hum, humerus; rod, radius ; ul, ulna ; ralf, radiale ? ; i, intermedium ; uln, ulnare ; pi, 

pisiforme; 1-5, carpals of second row; I-V, metacarpals. 

appears that Case has mistaken the upper border of the quadratojugal for the lower. The 
mandible was in perfect condition. The symphysis is represented as being equal to a very little 
more than one-third the whole length of a ramus. In addition to_the bones found in the lower 
jaw of ordinary turtles Case states that the bone called by Baur^he presplenial, by Williston 
the true splenial, is present. 

The bones described and figured by Cope as metapodials (Cope's plate xu, figs. 3, 4) are 
certainly not such, but epipodials. The original of his fig. 3 appears to be a tibia. The bone 
on the right of his fig. 4 may be a radius. The same bone in Archelon, as Wieland mforms 
the writer, is now regarded by him as the ulna. 

No. 1421 of the Carnegie Museum, Pittsburg, was secured in the Niobrara Cretaceous, 
near Hackberry Creek, Gove County, Kansas. It furnishes the nearly complete skull; the 
humerus, radius, ulna, most of the carpal bones, and some phalanges of the right flipper; and 
the nuchal and first three right peripherals. These bones are yet imbedded in the matrix, so 
that only their upper surfaces are visible. The remains have been studied and described by 
Wieland, whose figure is here reproduced (fig. 248). The following measurements of the skull 
are taken from his paper: 



1^4 FOSSIL TURTLES OF NORTH AMERICA. 

Millimeters. 

Extreme length of ramus of lower jaw 370 

Extreme length of symphysis of lower jaw 160 

Length of skull from beak to end of supraoccipital spine 580 

Median length of narial opening 75 

Width of narial opening 55 

Antero-posterior length of orbit 120 

It will be observed that this skull was nearly 2 feet in length. In Wieland's figure the 
suture between the parietals was omitted; but this is here supplied. 

It is unfortunate that only a portion of the nuchal was preserved. Its presence would have 
settled the question regarding the identity of the T-shaped bone, which has been regarded as 
the nuchal. The portion of the nuchal (fig. 248, iiu. p) remaining with this specimen does not, 
the writer believes, particularly favor the opinion that it is the T-shaped bone. 

No. 1393 of the Carnegie Museum was obtained at Twin Butte Creek, Logan County, 
Kansas. It is fragmentary, but presents various portions of the plastron, limbs, and skull. 




Fig. 249. — Protostega gtgas. X I's. Carapace of No. 1420 Carnegie Museum. 

I— 10, the ribs of the carapace; 5, sacral rib. 

Some series of the peripherals show that there was a sharp free border along each side. From 
this a plate of bone from 50 to 70 mm. wide rose over the distal ends of the ribs. From the 
same border another plate, from 25 mm. to 30 mm. wide, past horizontally inward below the 
rib-ends. The hyoplastron and the hypoplastron taken together measure about 400 mm. in 
length. The greatest thickness of the hyoplastron is about 15 mm. The hypoplastron is 
somewhat thinner. Both xiphiplastra are present. They are of the form shown in Case's 
figure, but they are not so abruptly bent. 

Little is known regarding the vertebrae of this species. Cope had remains of 5, but he was 
unable to determine where they belonged. They probably appertained to the tail. Cope 
supposed that the dorsal vertebrae possest transverse processes, but Wieland's figure shows 
this conclusion to have been erroneous. Wieland stated that a specimen at the Carnegie 
Museum furnisht 6 of the cervicals, but he did not describe them. Case describes 2 caudals. 
They were procoelous. 

The carapace of this species is of great interest, and has been studied by Cope, Case, and 
Wieland. Cope had secured portions of 10 ribs of the type specimen. He recognized clearly 



PROTOSTEGID^. 



195 



the fact that the costal plates were greatly reduced, so that the ribs were free from one another 
to near their proximal ends. He supposed that he had found evidences, from the great length 
of the costal plates from the origin of the rib-heads to the proximal border, that there were no 
neural bones, and that the rib-heads were attacht to transverse processes. He was undoubtedly 
wrong in both conclusions. Case had for examination only fragments of the ribs. He found 
that the neural borders of the costal plates were digitated; and from the considerable extension 
of these plates toward the midline from the origin of the rib-head, he concluded that there was 
no room for neurals. He found that the costal plates extended along the ribs for about a third 
of their length. Wieland had the opportunity to study a carapace, No. 1420 of the Carnegie 
Museum, which showed a nearly complete series of ribs. Fig. 249, reproduced from Wieland, 
shows this carapace as seen from below. He found the neurals to be present, but of papery 
thinness and much crusht down on the neural arches. Contrary to what is found in most 
turtles, the first rib is not turned backward against the second. It is relatively short. The 
other ribs are about 35 mm. wide at the middle of their length. The costal plates, forming the 




Fig. 250. — Protostega g'gas. Plastron. X ,'5. After figure by Case. 

«nr, entoplastron; /i;yo, hyoplastron ; A)ipo, hypoplastron ; jfipA, xiphiplastron. 
On the left is a number of peripherals. 

disk of the carapace, extend not more than one-third the length of the ribs. The total length 
of the ten dorsal centra was 680 mm. The distance between the distal extremities of the 
ribs of the fourth pair was 1060 mm. 

The nuchal bone of some members of the Protostegidae has already been discust. Cope 
figured a bone which he regarded as the nuchal. It is certainly a median bone, but it appears 
to be too small to be the nuchal, and may be the pygal. The nuchal may be supposed to 
resemble that oi Archelon, as figured by Wieland (Amer. Jour. Sci., v., 1898, p. 17). 

Of the peripherals Cope had 12, but the exact position of these could not be determined. 
They were, moreover, greatly flattened by the pressure to which they had been subjected. 
Some of these had only a single lamina, that rising to the ribs. Others possest, besides this, a 
lamina that projected toward the bones of the plastron. The end of a rib was partly buried m 
the lower surface of the upper lamina of each. The external border of each peripheral behmd 
the second was acute. The upper lamina was thin and its upper border terminated in digita- 



196 



FOSSIL TURTLES OF NORTH AMERICA. 



tions. We are indebted to Case for more exact knowledge of the peripherals. He had a series 
of 8 of these in their natural order (fig. 250). The most anterior was supposed to be the second. 
It is slender, concave along its free border, as if to make room for free movements of the limb, 
and has no pit for a rib. It is 170 mm. long and only 30 mm. wide. The third is strong, broad, 
and has a rib-pit. Its length is 170 mm. and its width 118 mm. The succeeding ones are longer 
than wide and have 2 laminae, the uppermost of which is the broader. All these peripherals 
are closely joined together by means of coarse sutures. 

^Wieland figures (Mem. Carnegie Mus., 11, p. 282) a portion of a nuchal bone and the first 
and second peripherals. The figure is here reproduced (fig. 248). 

The hyoplastra and the hypoplastra were described by Cope as dermal bones that were 
supposed to overlie the ribs. Baur's suggestion that these bones belonged to the carapace has 
been mentioned. They had been comprest until the greatest thickness was only about 15 mm. 
A plastron described by the present writer showed that these bones were really thick and heavy, 
the thickness amounting to as much as 45 mm. in the case of the hyoplastron. The plastron 
described by Case (fig. 250) was somewhat larger than the one last referred to and furnisht 
representatives of all the elements except the epiplastra. The hyoplastra and hypoplastra are 
bones of an irregularly triangular form, with all the borders digitated, except over the fore and 



met. 
phal. 




Fig. 251. — Protostega gigas. Right shoulder-girdle and limb; dorsal view. XA. 

c, centrale; cor, coracoid; hum, humerus; Int, intermedium; I-V, the digits; met, metacarpals; phal, first row of 
phalanges; pi, pisiforme; pcor, procoracoid process; rod, radius; ul, ulna; uln, ulnare; 1-5, carpals of second row. 

hinder limbs. From the anterior inner angle of the hyoplastron a thickening, appearing on the 
lower surface as a low ridge, runs backward thru the articulation with the hypoplastron and 
on backward to the xiphiplastra. From this ridge, in each direction, the thickness is reduced 
until the borders are reacht. Evidently there were considerable spaces left between the plastral 
bones and the peripherals. In the midline there was a great fontanel, which extended from 
the entoplastron to the xiphiplastra. The union of the plastral bones with the peripherals was 
a ligamentous one. 

As stated, the entoplastron was first described by Hay as a nuchal. Case figured a more 
complete specimen as a nuchal. This was found lying with its wings overlapping the anterior 
ends of the hyoplastra (fig. 250). It extended from side to side a distance of 599 mm. The 
greatest breadth of the wings was 131 mm. From the midline of the bone there reacht back- 
ward a spine which must have attained a length equal to that of the wings. The outline of this 
bone was concave in front to middle of wings, then convex. The epiplastra are unknown. 

The xiphiplastra are remarkable bones. Instead of extending backward and gradually 
inward as they do in the Cheloniidae, just behind their articulation with the hypoplastra they 
turn directly inward at almost a right angle, to meet at the midline by an overlapping joint. 

The limbs of this species, as of all the Protostegidae, are modified for permanent residence 
on the seas. 



PROTOSTEGID^. 



197 



Cope described and figured the humerus and some other hmb bones. Case also added to 
our knowledge of the limbs ; to Wieland most of all we are indebted for their complete restora- 
tion. The materials furnishing his observations are in the Carnegie Museum, at Pittsburg. 
The scapula, with its procoracoid process, is a stout bone. The coracoid is so long that it 

reacht the pelvis. The humerus is greatly modified, resem- 
bling in some respects that of Dermochelys. The fingers are 
elongated to form a great paddle for beating the sea. The 
length of this limb, from the glenoid cavity to the tip of the third 
finger, is estimated by Wieland as being 1060 mm. The greatest 
spread of the fore limbs is supposed to have been 2500 mm. For 
details on the structure of the flippers the student is referred 
toWieland's paper and to the figure here presented (fig. 251). 
Fig. 252, reduced from Wieland's paper, represents a 
humerus of Protostega now in Carnegie Museum. The total 
length is 340 mm. 

Fig. 253, taken from Wieland, represents the hinder limb 
and the pelvis. Both the pelvis and the limb resemble closely 
those of the Cheloniidae. The ilium is a stout bone. The 
ischium and the pubis appear to have met on the midline. The 
hinder limb, in comparison with the fore limb, is relatively 
longer than it is in most Cheloniidae. The greatest spread of 
the hinder flippers is given as 1900 mm. Wieland thinks that 
four of the toes were clawed. 

Estimates varying greatly have been made regarding the 
size of this sea-turtle. It is highly probable that earlier esti- 
mates made by Cope and Hay were too great. Cope concluded 
that his specimen had a total length of 12.83 feet, about 3900 
mm. From the specimen studied by Hay about the same con- 
clusion was reacht. The discovery by Case that the plastron 
was much shortened behind caused him to conclude that the 
total length was considerably less than had been supposed. He estimated the length, including 
the head, as about 2270 mm. He made the length of the carapace as 1640 mm., the width as 
12^5 mm. However, if we may judge from the carapace described by Wieland, the width 




Fig. 



252. — Protostega gig as. 
Humerus. xJ. 

e, ecteplcondylar passage. 




Fig. 253. — Protostega gigas. Pelvis and hinder limb. Xj. 

aiU, astragalo-calcaneum; fern, femur; fb, fibula; I-V, the digits; ,7, ilium; isch, ischium; met, metatarsals; 
p, first row of phalanges ; /)u4, pubis; (/i, tibia ; 1-5, tarsals of second row. 

was considerably greater than the length. It is now estimated that the length of the carapace 
of the Pittsburg specimen was about iioo mm. and the width about 1200 mm. The total 
length of the animal then must have been perhaps something over 2 meters. Its humerus 
was 340 mm. long; that of Cope's type, 300 mm. 



198 



FOSSIL TURTLES OF NORTH AMERICA. 



As regards its habits, we may safely conclude that this turtle was an active swimmer on the 
open seas and that it was carnivorous in its diet. Wieland is of the opinion that all the members 
of this group were powerfully equipt for both swimming and attack, and may well have 
hunted actively swimming prey. As to swimming, we must remember that the boldest swimmer 
among turtles of our day is the leatherback, which has an elongated body. The short, broad 
carapace of Protostega must have imparted to the animal an unsteady bearing under efforts to 
make rapid progress. 

As regards the nature of the food, the long symphysis of the lower jaw appears to indicate 
a habit of crushing hard-shelled animals, such as crustaceans and mollusks. 

Protostega potens sp. nov. 
Figs. 246, 254, 255. 

This species has as its type No. 180 of the American Museum of Natural History. This 
was collected by Mr. H. T. Martin, in 1897, in the Niobrara beds, near Elkader, Logan 
County, Kansas. The individual is represented by large portions of the skeleton, but only a 
part of it has been prepared for study. 

There is present the hinder half of the left side of the skull. This is strongly crusht down- 
ward and toward the right side. The structure appears to be in general the same as in P. 




Figs. 254 and 255. — Protostega potens. Basioccipital and hyoplastron of type. 
254. Section across front of basioccipital. Xi- 255. Hyoplastron. Xj. 

gigas. Sutures are not discernible, but from the striations on the bones, their limits may be 
pretty accurately determined. The orbit had a perpendicular diameter of 70 mm. The dis- 
tance from the hinder border of the orbit to the posterior angle of the squamosal was nearly 
200 mm. On lifting the anterior end of the parietal there is exposed a broad plate of bone 
which runs downward from the inner border of the parietal. This is without doubt the descend- 
ing plate of the parietal, whose presence has hitherto been somewhat doubtful. The occipital 
condyle is large, having a diameter of 50 mm. The bones composing it are wholly co-ossified. 
Its inferior portion is eroded away. The condyle is broadly rounded behind, without trace 
either of a pit or of division into its constituent three bones. The lower surface of the basi- 
occipital appears to have been greatly different from that of P. gigas. Case describes the latter 
as having its under surface nearly smooth and lying in the plane of the horizontal axis of the 
skull. From this we may infer that this surface is nearly flat. In the present species the midline 



protostegidj?;. 199 

of the bone is traverst by a prominent ridge, the summit of which anteriorly is about 10 mm. 
wide and which expands posteriorly to the condyle. The sides of the ridge are formed by two 
bold grooves which run backward and outward from the front of the bone. Whether or not any 
portion of the basisphenoid is present in the fragment of bone 60 mm. long from the occipital 
condyle is not certain. Fig. 254 is a section taken near the front of the fragment. The summit 
of the ridge has been eroded off. 

The carapace is represented by the midline and the ribs of the left side. It resembled that 
of P. gigas, as represented by Wieland, but the ribs are free from one another to points nearer 
the midline. The neurals are crusht down against the vertebrae and most of them have been 
subsequently eroded away. The boundaries of none can be traced. The distance from the 
base of the first rib to that of the tenth is close to 800 mm.; the length of the first rib is 205 mm., 
that of the fifth at least 655 mm. The carapace must have had a length of about 1250 mm. 
and a width of about 1500 mm. The ribs are free from the adjoining ones to about 120 mm. 
of the midline. 

Large portions of the plastron are preserved, but all have not yet been made available for 
study. The right hypoplastron is nearly complete. Its lower surface is traverst by a low 
longitudinal ridge. The length of the bone along this ridge is 400 mm. The width is nearly as 
great. The right and left borders are furnisht with numerous digitations. At the hinder end 
is a notch for the reception of the xiphiplastron. Most of the process of the hypoplastron 
which joined the xiphiplastron on its outer border is broken away. 

The xiphiplastron (fig. 246, xiph) is remarkably thin, being nowhere more than 10 mm. 
thick. It is not so abruptly turned toward the midline after being freed from the hypoplastron 
as is that of P. gigas. Its length was originally close to 375 mm. Beyond the hypoplastron 
both of the borders are acute; the inner is the thinner. The outer border joined, for more than 
the proximal half of its length, a process of the hypoplastron. 

The left hyoplastron (fig. 255) is present. Unfortunately many digitations are lost, so 
that not all its dimensions are determinable. From the hyohypoplastral suture to the 
anterior end the length is 580 mm., measured on a straight line. From the just-named suture 
to the bottom of the axillary notch the distance is 300 mm. The entire width of the bridge was 
not far from 625 mm. The low ridge seen on the hypoplastron is continued forward on the 
hyoplastron. The suture between the hyoplastron and the hypoplastron was evidently consid- 
erably shorter than in P. gigas. Here the bone is about 25 mm. thick. 

The T-shaped entoplastron (fig. 246) is preserved, but lacks much of the lateral wings. 
The lower surface is mostly convex, but on the outer end of each wing it is slightly concave in 
all directions. The visceral surface is concave from side to side. Near the front border, at 
a distance of about 25 mm. from the midline, begins a broad groove, quite deep at first, but 
becoming shallower on the wings. This was almost certainly occupied by the epiplastron. 
At the midline, near the anterior border, the bone is about 20 mm. thick. About 50 mm. from 
the midline, on each side, there is a rough surface, as if for a ligament. To this may have been 
tied the anterior end of the procoracoid process of the scapula. At the outer end of the right 
wing, as preserved, the thickness of the bone is only 6 mm. Here the surface which was 
covered by the epiplastron is 65 mm. wide. 

The left scapula, without the procoracoid process, is preserved. Its length, from the upper 
end to the glenoid fossa, is 275 mm. The coracoid has a length of 425 mm., and a small portion 
of the distal end is missing. It was not expanded at the distal end. The left humerus is well 
preserved and not much crusht. The total length is 402 mm.; from the head to the distal end, 
385 mm. From the head to the lower end of the radial process is 245 mm. The width of the 
distal end is 185 mm. The ectepicondylar passage is a foramen with a large opening on the 
articular surface. 

One femur, much distorted by pressure, is present. Its length is 335 mm. The diameter 

of the shaft is 50 mm. 

Protostega advena sp. nov. 

Figs. 256-259. 

The chelonian remains to which the name Protostega advena is given are the property of 
Kansas University and have the number 1209. There is no history of the time or place ot 



200 



FOSSIL TURTLES OF NORTH AMERICA. 



collection or of the collector. There is no doubt, however, that the specimen was obtained 
from the Niobrara deposits of Kansas. It consists (fig. 256) of the greater portion of the 
plastron, 12 peripherals, 2 or 3 neurals, and portions of 2 costal plates. With these are some 
other bones which are either undetermined or they doubtfully appertain to the specimen. 
The hyoplastra and hypoplastra closely resemble those of Protostega gigas. The two of 
these bones which are found on the same side were apparently united for a short distance by 
a coarse suture. The two hyoplastra evidently came close together along the midline; but 
the hypoplastra were widely separated. The median fontanel has therefore extended from 
the hyoplastrals to the xiphiplastrals. The latter bones are not so elongated as in modern 
sea-turtles and Chelydra, nor so short and abruptly incurved as in Protostega gigas. The 
greatest thickness of the hyoplastrals is about 10 mm. The other plastral bones are thinner. 
There are no longitudinal carinae on the plastron, such as we find on that of Caretta caretta 




Figs. 256-259. — Protostega advena. Portions of type. Xj. 

256. Plastron and peripherals, seen from above. 257. Two neurals. 258. Costal bone. 259. Postfrontal. 

and Protostega gigas. The forms and positions of the various bones may be seen from the 
figures. The distance from the anterior border of the hyoplastron to the hinder border of 
the xiphiplastron is 278 mm. The entoplastron and the epiplastra are wanting. 

The anterior peripherals of both sides are absent from the materials. On the right side 
the most anterior peripheral present appears to be the one which has received the rib-end of 
the first costal plate. This is provisionally regarded as the fourth from the nuchal bone. 
The most anterior one on the left side is the fifth. On the left side one is believed to be missing 
next to the pygal; while on the right side three in front of the pygal are supposed to be gone. 
These peripherals prove that this individual is not a young Protostega gigas, since they are 
relatively much shorter and broader than are the corresponding bones of the latter species. 
They are likewise much heavier bones. 



PROTOSTEGID^. 201 

Each of the peripherals, except the posterior three, may be said to be V-shaped in trans- 
verse section, one limb of the V extending toward the edge of the plastron, the other inward 
and upward toward the costal plate. The upper plates are slightly concave above; the lower 
ones somewhat convex below. The concave and the convex surfaces of each peripheral come 
together to form a sharp edge, and the border of the carapace so formed runs from the fourth 
peripheral to near the pygal. The three posterior peripherals have no lower, or plastral, 
plate developt. What is regarded as the tenth peripheral has a half-pit at its hinder end. 
It is therefore believed that the rib-end of the eighth costal was swung backward to be inserted 
between the contiguous ends of the eleventh and the twelfth peripherals. In Caretta this rib- 
end has moved backward still further and is inserted in the middle of the last peripheral. 

The antepenultimate peripheral has a pit for the rib-end of the seventh costal near its 
hinder end and this pit lies partly in the anterior end of the penultimate peripheral. If the 
eighth costal plate is regarded as sending its rib to the last peripheral, the next peripheral in 
front has no rib-end corresponding to it. In Caretta it is the antepenultimate peripheral 
which receives no rib. 

The peripherals are smallest posteriorly, and they increase in size as far forward as they 
are represented. The fourth, the most anterior one present, has its two plates standing at an 
obtuse angle with each other; the fifth has them at nearly right angles, the others at less than 
a right angle. The plastral plate of the fifth is 37 mm. wide, the carapacial plate is 30 mm. 
wide. Two long narrow peripherals accompany the specimen, but they appear to be intrusive 
and to belong to Toxochelys. Two neurals (fig. 257) are present, probably the third and the 
fourth. The more anterior is 39 mm. long and 28 mm. wide; the other 30 mm. long and 25 
mm. wide. The middle line of each rises into a low carina, which on the more anterior one 
rises into a tubercle. The hinder end of the anterior neural is crost by a narrow dermal 
sulcus, a fact which shows that dermal scutes were present. The peripherals also are crost 
by sulci, but these are broader than that on the neural. 

The pygal is a rather peculiar bone, being nearly square, thick, convex on the hinder, 
or upper, surface, and with a thick free border. It is 27 mm. high, 33 mm. wide and 11 mm. 
thick. 

With the remains described is found a detacht median dorsal tubercle exactly like those 
occurring in the dorsal carina of Toxochelys; but it is regarded as foreign to the specimen, 
having probably been introduced with the peripherals just mentioned. 

Fig. 258 represents a costal plate of this species. It will be seen that it is less completely 
ossified than the costals of our modern sea-turtles, but more completely than in even a large 
Protostega gtgas. In the figure the distal end is restored in outline from another costal present. 
Measured thru the middle of the width the costal is 7 mm. thick, but near the sutural 
border it becomes reduced to 3 mm. The costal figured is probably the fifth of the right side. 
On it are found the sulci which separated two vertebral scutes from each other and from a 
costal scute. These sulci are narrow and shallow. It is evident that the vertebral scutes 
were relatively very broad, about 1 10 mm., nearly equal to one-third the width of the carapace. 

There are present two bones which are referred to the skull; they are the two postfrontals 
(fig. 259). Each is 30 mm. wide and 60 mm. long. At the hinder end the bone thins down 
to a sharp, nearly smooth edge; so that it becomes probable that this edge formed the hinder 
border of the roof of the temporal region; and hence, that the squamosal did not join the 
parietal. The roof was probably not so extensive as in Caretta. 

In the Cope collection of the American Museum of Natural History is the left humerus 
of a small sea-turtle which was collected in Gove County, Kansas, in 1877, by one of Professor 
Cope's collectors. This humerus has every appearance of being that of an adult turtle. It has 
suffered no compression or distortion whatever. Its length, from the proximal surface of the 
head to the distal end of the bone, is 64 mm. The ulnar process rises slightly above the head. 
The radial process descends 35 mm. below the proximal surface of the head. This process 
is II mm. thick. The width of the humerus across this process is 23 mm. Just below the 
process the width is 16 mm. On the upper surface of the bone, opposite the radial process, 
is a deep muscular scar. At the distal end there is nearly a right angle between the surface 
for the radius and that for the ulna. The ectepicondylar passage is a shallow groove close to 
the radial border. 



202 



FOSSIL TURTLES OF NORTH AMERICA. 



A wholly similar humerus is contained in a small collection of bones sent the writer from 
the University of Chicago. The few skeletal bones accompanying it are not sufficient to 
identify the humerus as that of P. advena, but it seems probable that both it and the humerus 
in the American Museum belong here. 

Genus ARCHELON Wieland. 

Premaxillary beak more strongly developt than in Protostega. Crushing-surface of upper 
jaw mostly on the premaxillaries; that on the maxillae extending back only to opposite the 
choanae. Lower jaw with the rami not co-ossified at symphysis; at least, not until old age. 
Entoplastron T-shaped, with the anterior border concave from end to end. Radial process 
of humerus feeble. 

Type: Archelon tschyros Wieland. 




Fig. 260. — Archelon ischyros. Carapace with the entoplastron. Xa'n. 

Archelon ischyros Wieland. 
Figs. 260-268. 

Archelon ischyros, V^lt.tAND, Amer. Jour. Sci. (4), II, 1896, p. 399, plate vi, text-figs. 2-19; ibid., IX, 

1900, p. 237, plate ii, text-figs. 1-3, 6; ibid., xiv, 1902, p. 99, fig. 2; ibid., xv, 1903, p. 211, fig. i; 

Ann. Carnegie Mus., iv, 1906 (1907), p. 8, figs, i, 4. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 

1902, p. 440. 
Protostega ischyros, Williston, Univ. Gaol. Surv. Kansas, 11, 1897, p. 246. — Wieland, Anier. Jour. 

Sci. (4), V, 1898, p. 15, plate ii, text-figs. I, 2. 

We owe our knowledge of this species to the study and the publications of Dr. G. R. 
Wieland. All the known specimens have been found by him near the South Fork of Cheyenne 
River in South Dakota, in the upper beds of that part of the Pierre formation that is below 



PROTOSTEGID^. 



203 



the Judith River formation. The species was probably the largest that is at present known 
to have existed. From the length of the neck and the carapace Wieland estimates that the 
total length of type specimen was about 3.5 meters. Specimen in Yale University collection. 
Of the remains of this great turtle the present writer has studied only the skull. The 
greater part of the description here given has been derived from Wieland's papers. The 
figures are reproduced from those papers. Fig. 260 represents the carapace as shown in 
Wieland's latest restoration of it (Amer. Jour. Sci., xv, p. 212). In this figure (p. 189) a large 
bone is shown in front as the nuchal but which the present writer regards as the entoplas- 
tron. This figure is based on the type specimen, except that the first rib is added from 
another individual. The carapace, so far as is known, was composed of 8 neurals, I or 
more suprapygals, 10 pairs of ribs, a nuchal, a pygal, and an undetermined number of pairs of 
peripherals. 

The estimated total length of the carapace, exclusive of the nuchal, is 1.7 meters; with the 
nuchal, it was probably about 1.9 meters. The width, exclusive of the peripherals, must have 
been about 2 meters; including the peripherals, about 2.5 meters. 

The neurals are mostly broader than long. Their borders are furnisht with long and 
coarse digitations, which interlock with others from the contiguous neurals and costal plates. 
It is difficult, therefore, to determine the widths of the neurals, but these widths may be taken 
as from 175 mm. to 225 mm. The neurals are relatively thin, being only about 5 mm. The 
median line of most of the neurals is markt by a deep and narrow groove, which becomes 
widest at the center of the neural. From this center there radiate outward characteristic 
surface striations. In his first description Wieland thought that these neurals probably con- 
sisted each of paired bones. He concluded also that the longi- 
tudinal groove was filled with horny materials and that the animal 
may have borne a row of dorsal spines. The last one or two 
neurals and the suprapygals have not been well determined. 
Little can be said concerning the pygal. Indeed, the terminal 
bone shown in Wieland's figures of the carapace is probably a 
suprapygal. 

The ribs and the costal plates resemble much those of Pro- 
tostega. The disk formed of the costal plates and the neurals is 
much reduced, extending outward from the median line hardly 
one-fifth the distance to the ends of the ribs Beyond the borders 
of the disk the ribs are wholly free from one another. The first 
rib is extraordinarily large, as compared with the same rib in other turtles, being three-fourths 
as long as the second. Its length is 740 mm.; its diameter, about 75 mm. The other ribs have, 
in the type specimen, the dimensions shown in the table. 

Where the ribs emerge from the disk their thickness averages only about 25 mm. It is 
thus seen that they increase much in thickness toward the middle of their length. 

The bone described by Wieland (Amer. Jour. Sci., v., 1898, p. 17) as the nuchal (fig. 261) 
and now regarded by the present writer as such, is roughly triangular, with a concave anterior 
border. The lateral extent of the bone is 640 mm.; its antero-posterior extent, 250 mm. On 
the inferior surface there is a trapezoidal elevation, which Wieland regarded as having afforded 
an articulation with the last cervical vertebra. The thickness through the elevation is 35 mm.; 
elsewhere, from 10 mm. to 15 mm. 

Little has yet been publisht about the peripherals. A fragment of one was figured by 
Wieland in his earliest description of this turtle. In a later paper (Amer. Jour. Sci., xv, p. 2 1 1 ) 
he states that the inner borders of these bones are strongly digitated. 

The plastron (Amer. Jour. Sci., v, p. 16) has the same general structure as that of Pro- 
tostega, altho the principal bones appear to have been broader and to come nearer filling up the 
median fontanel (fig. 262). As represented by Wieland, the digitations bordering them are 
extraordinarily numerous and elongated. The T-shaped entoplastron (fig. 262, eni) has a 
breadth of 940 mm. and a length of 450 mm. The anterior border is concave to the outer 
extremities, thus diff'ering from that of Protostega. The extremities of the wings are 280 mm. 
wide. They appear in the figure to occupy their natural position on the hyoplastra. The 



Rib. 


Length. 


Width at 
middle part. 


2 


950 


"1 
75 


3 


lOIO 


75 


4 


1020 


78 


5 


1020 


75 


6 


lOIO 


70 


7 




65 


8 





60 


9 




55 


10 




50 



204 



FOSSIL TURTLES OF NORTH AMERICA. 



greatest thickness of the entoplastron, at the midline, is 60 mm.; at the narrowest part of the 
lateral portion, 50 mm. The epiplastra probably overlapt the entoplastral wings nearly to the 
midline and ran backward a short distance on the borders of the hyoplastra. Wieland (Ann. 
Carnegie Mus. iv, p. 8) describes what he regards as the epiplastron. For the present writer's 
opinion on this, the reader is referred to page 190. 

The hyoplastra (fig. 262, hyo) have each an antero-posterior length of 1030 mm.; while the 
width, inclusive of the spines, is 1 100 mm. The greatest thickness is 48 mm. The articulation 
with the hypoplastron is about 150 mm. wide. 

The hypoplastron (fig. 262, hypo) from the hyoplastral articulation to the extremities of 
the processes embracing the xiphiplastron, has a length of about 960 mm. The greatest 
breadth, including the spines, is 1000 mm.; the greatest thickness is 41 mm. 




Figs. 261 and 262. — Archelon ischyros. Xso. Nuchal bone and plastron of type. 
261, Nuchal bone. 262. Plastron, ent, entoplastron; hyo, hyoplastron; hypo, hypoplastron; xiph, xiphiplastron. 

The xiphiplastra (fig. 262, xiph) are each 500 mm. long, 170 mm. wide, and 36 mm. thick. 
The proximal end of each fits in between processes of the corresponding hypoplastron, being 
grooved to receive the borders of those processes. The distal ends of the two xiphiplastra join 
at the midline by interlocking digitations. These bones are less abruptly curved than are 
those of Protostega, and greatly resemble those of Protostega advetia. 

The total length of the plastron, according to Wieland's figure, is about 2100 mm., being 
thus longer than the estimated length of the carapace. The latter was certainly the longer. 

The skull (fig. 263) of this species reacht an enormous size both relatively to the length of 
the carapace and absolutely. Wieland's restoration of the one studied by him is here repro- 
duced. The same individual furnisht also a nearly complete skeleton. It was about three- 
fourths the size of the type specimen. The skull has a length of 720 mm. Another, but 
fragmentary specimen, indicated a skull fully a meter in length. 



PROTOSTEGID^. 



205 



Points to be especially noted in this skull are its long and narrow form, the long preorbital 
region, the hookt beak, the posterior position of the orbits, and the upwardly directed nasal 
opening. Contrary to what is usually seen in turtles, the orbits are placed in the middle of the 



sq- 




-pmx 



Fig. 263. — Archelon ischyros. Skull. Xj. 

an^, angular; art, articular ; <f«n, dentary; /r, frontal; ^u, jugal ; mx, maxilla; nar, 'nares; pr/, "prefrontal; pal, 
palatine; pmx, premaiilla; pa, parietal; poj, postfrontal; qu, quadrate; quj, quadratojugal; sq, squamosal; 
J/, stapedial rod ; J«r, supraangular; vom, vomer. 

length of the head. This results from the great development of the preorbital region. The 
horizontal diameter of the orbit is 150 mm. 

Both the maxillae and the premaxillae are greatly prolonged. The distance from the tip 
of the beak to the anterior rim of the orbit is 240 mm. ; from the orbit to the suture between the 





Figs. 264 AND 265. Archelon ischyros. Skull. 

264. Palatal surface. Xj's. bsp, basisphenoid; cho, cho- 
an^; y'u, jugal; mx, maxilla; of, occipital condyle; 

pal, palatine; pmx, premaxilla; pi, pterygoid; qu, 
quadrate; yw/", quadratojugal ; 5y, squamosal; vom, 
vomer; vp, vomero-palatine region. 

265. Side view of front. X\. mx, maxilla; nar, nares; 
0, orbit; pal, palatine; pmx, premaxilla; prf, pre- 
frontal; vom, vomer. 

maxilla and the premaxilla is about 150 mm. The tip of the premaxillx is bent down at nearly 
a right angle with the axis of the skull, forming a great hawk-like beak. The nasal opening 
looks wholly upward. Its length is 120 mm.; its width, 70 mm. 



2o6 



FOSSIL TURTLES OF NORTH AMERICA. 



From the front of the orbit to the quadrate the free borders of the maxilla, the jugal, and 
the quadratojugal form a nearly straight line. Above the orbit the prefrontal meets the 
postfrontal, thus excluding the frontal from the orbital rim. The relations of the bones behind 
the orbit are in general like those oi Protostega. In describing the (juadratojugal of Protostega 
Case appears to have inverted the bone and this has led Wieland to suppose that the bone 
mentioned and others of the region are different in Archelon. Wieland's figure of the skull 
oi Protostega show^s that the region in question is the same in both genera. The squamosal is 
figured by Wieland as sending a process upward to meet the parietal. Probably the same 
occurs in Protostega. The supraoccipital is represented as very short, but there is probability 
that it was longer. The width across the quadrate region is about 350 mm. 

Various interesting structures appear on the palatal surface of the skull (figs. 264, 265). 
As in Protostega, the basioccipital was small. The basisphenoid too appears to have been 
small, but it is not well known. The pterygoids are extremely narrow. The exact relationships 




Fig. 266. — Archelon ischyros. Shoulder-girdle, humerus, and a cervical vertebra. Xi'n. 

cer.Vj third or fourth cervical vertebra; the figure on the right giving front view, that on the left a side view. 
cor, coracoidj hum, humerus; scap, scapula. 

of the palatines are not known. The hinder end of the vomer is missing, but it is probable that 
it interposed between the palatines. The choanae were placed far forward, immediately below 
the external nares, and were not underfloored by the surrounding bones. The great crushing- 
surface of the upper jaw was developt mostly on the premaxillaries, an unusual thing among 
the turtles. On the maxilla this surface extends backward only to opposite the choanae. 
Behind these, the free border of the maxilla is narrow and weak. The crushing-surface was 
therefore about 240 mm. long and about 140 mm. wide across the vomer. The anterior portion 
of the vomer formed a boss in the center of the crushins-surface. 

The lower jaw (fig. 263) was massive. Its lateral halves were not co-ossified, thus differing 
from those oi Protostega. The symphysis has a length of 120 mm., the total length of the jaw 



PROTOSTEGID^. 



207 



being 465 mm. At the hinder end of the symphysis its depth is no mm., and the width of 
the jaw, 155 mm. On the under surface the symphysial end of the jaw turns strongly upward, 
but the upper surface rises little. Wieland found the splenial to be present. 

Wieland has described 5 cervical vertebrae (fig. 266, cer. v) which belonged to the type 
specimen (Amer. Jour. Sci., 11, p. 401; xiv, p. 102). These centra indicate a neck of great 
strength. The centrum of one, regarded as the third or the fourth, is procoelous, 95 mm. long 
and 140 mm. wide. Dorsal, sacral, and caudal vertebrae also are described by the same author. 

The shoulder-girdle of the type specimen was described by Wieland (Amer. Jour. Sci., 
II, p. 404). The scapula (fig. 266, scap) is a stout and heavy bone, resembling that of Pro- 
tostega. The length of the body of this bone, from the upper end to the glenoid fossa, is 
450 mm. The coracoid (fig. 266, cor) is elongated and slender, as in Protostega. The length is 
650 mm., the width of the distal end, 127 mm. 




Fig. 267. — Archelon ischyros. Limb bones. X I'o. 

fern', left femur, dorsal surface ; fern", left femur, tibial border ; jem"', proiimal end of left femur, fibular border ; 
fh, fibula ; hum, left humerus ; rad, ulna ; tih, tibia ; ul, radius. The bones marked rad and ul should 
exchange places, be placed with the other ends up, and exchange explanatory letters. 

The humerus (figs. 266, 267, hum) is an enormous bone, the length from the head being 
580 mm.; the total length, 650 mm. The width of the distal end is 340 mm. This bone differs 
from that oi Protostega in having a relatively smaller head and the radial process much reduced. 
Wieland describes also the radius, the ulna, and some phalangeal bones. The figures by 
Wieland are here reproduced. In the figure of the fore Hmb the upper ends of the ulna and 
the radius have mistakenly been represented as the lower. When the ends are reversed they 
will have the positions that they have in Wieland's figure of the anterior flipper of Protostega 
gigas. The bones must also exchange places and legends. 

The pelvis of the type specimen is described and figured in the journal so often quoted 
(vol. IX, p. 247). The figure is here reproduced (fig. 268). This pelvis is of astonishing size, 
the length and the width being each nearly half the length of the carapace. In general, its 



208 FOSSIL TURTLES OF NORTH AMERICA. 

Structure resembles that of the pelvis of the Cheloniidae, but it differs in having a median 
bridge of bone connecting the pubes and the ischia. In this way ischio-pubic foramina are 
formed, but they are of small size. As stated by Wieland, the extreme antero-posterior length 
of the pelvis is 970 mm.; the extreme width, 810 mm. The fore-and-aft length of the pubis 
is 460 mm. The length of the ilium is 300 mm., and its diameter, at the middle of the shaft, 
is 105 mm. 

The femur (fig. 267, fern) has the ratio to the humerus that it has in Caretta caretta. Its 
extreme length is 460 mm. The tibia (fig. 267, tih) has a length of 330 mm.; the fibula (fig. 267, 
fib) a length of 310 mm. 

As in the case of Proiostega, we can not doubt the adaptation of this turtle to marine 
aquatic life. Its excursions on land must have been confined to those for the deposition of 




Fig. 268. — Archelon ischyros. Pelvis seen from below. Xi*o. 
it, Qium; ip, ischio-pubic foramen; isch, ischium; pub, pubis. 

its eggs. We can only speculate as to what extent it spent its life on the high seas away from 
the coasts. It seems probable that the broad and heavy body and the ponderous head were 
obstacles in the way of sustained journeys over rough seas. Its prolonged beak, furnisht 
with a broad crushing-surface, appears to indicate a diet, not of soft and actively swimming 
animals, but of mollusks and crustaceans. Associated with the fossil were various genera of 
tetrabranchiate cephalopods, and the jaws of the turtle seem to have been admirably adapted 
to pick up and crush such objects. 

Archelon marshi Wieland. 

Archelon marshii, Wieland, Amer. Jour. Sci. (4), ix, 1900, p. 248; ibid., xv, 1903, p. 215. — Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 440. 

This species was secured by Wieland in the upper beds of the Pierre formation, in South 
Dakota, on the east side of the South Fork of the Cheyenne river. It is described in the 
briefest terms. The remains are stated to consist of the plastron, the humerus, ribs, and a 
number of peripherals. These indicate a turtle about 1 1 feet in length. The humerus is 
said to be rather straighter than that o{ J. ischyros and the plastron relatively more massive, 
being fully one-half thicker than in the latter species. 

Family CHELONIIDJE Gray. 

Thecophorous turtles fitted for life on the sea. Skull with temporal region extensively 
rooft over. No nasal bones. No posterior palatine foramina. Quadrate notcht behind for 



CHELONIID^. 209 

the stapedial rod. Choanae placed on the line joining the centers of the orbits; the nasal 
passages underfloored by plates from the vomer and the palatines. Neck short, head not 
retractile. Carapace heart-shaped, excavated in front for the neck and for the fore limbs; 
often with costo-peripheral fontanels. Plastron loosely and ligamentously joined to the cara- 
pace; usually with median and lateral fontanels. Entoplastron small and lance-shaped. 
Limbs unfitted for locomotion on the land; converted into paddles for swimming; the anterior 
the more powerful. Humerus straightened and flattened; with the head nearly in the axis 
of the bone and with the ulnar and radial processes nearly in the plane of the distal end; 
the radial process below and free from the head. Second to fifth fingers elongated, the phalanges 
without condyles; and all bound together in the skin and muscles. Claws I or 2. 

At the present day the Cheloniidae are represented by probably 4 genera {Eretmochelys, 
Colpochelys, Caretta, and Chelonia) and 5 or 6 species. Most, if not all, of these species 
enjoy a wide distribution, being found in all tropical and subtropical seas. All are seafaring 
animals, coming on the land only to deposit their eggs. They are mostly carnivorous in their 
food habits, but Chelonia feeds on vegetation. 

If Allopleuron hoffmanni, of Holland, belongs to this family, as usually supposed, the 
family history extends backward to Upper Cretaceous times. Well-preserved remains of 
sea-turtles belonging to the divisions of the Tertiary are not common. In America we have 
a few species which are here assigned to the family with some doubt; such as those of Peri- 
tresius of the Upper Cretaceous of New Jersey and Georgia and Lembonax of the Eocene of 
New Jersey. It can hardly be doubted that Syllomus crispatus of the Miocene of Virginia 
belongs to the family; while it is probable that the species here called Procolpochelys grandava 
and Chelonia parviiecta are also true Cheloniidae. All of these are, however, imperfectly 
known. In Europe the known Tertiary forms are hardly more numerous or better known. 

Allopleuron hoffmanni is greatly specialized in some respects. Especially is its carapace 
much reduced. It is improbable that from it have been derived the modern Cheloniidae. 
It is more likely that the latter have descended from some Upper Cretaceous ancestor not 
distant from Toxochelys. The ancestors of Allopleuron must have become sea-turtles long 
before the Upper Cretaceous— consequently long anterior to the time when the ancestors 
of our modern Cheloniidae could be called sea-turtles. It is therefore probable that Allo- 
pleuron really belongs to a family distinct from the Cheloniidae. 

Key to Genera here Described. 

A. First costal articulating with peripherals. Shell coarsely sculptured as in some 

Trionychids Per'tresius 

A A. Costal plates articulating to peripherals and sculptured Syllomus 

AAA. Costal bones, so far as known, not articulating with peripherals and not sculptured. 

a. Plastral bones without median digitations Lembonax 

aa. Plastral bones with median digitations. 

b Some neurals in contact with three pairs of costals. Rib of first costal entenng 

pit in third peripheral ;■•••. Procolpochelys 

bb Neurals in contact with two pairs of costals. Rib of first costal entenng pit in 

third peripheral Chelor„a 

Genus PERITRESIUS Cope. 

Carapace cordate, as in the Cheloniidae generally; the anterior peripherals suturally 
joined to the costals of the first pair; the posterior peripherals joined to costals by gomphosis 
of ribs only; a high dorsal keel; surface of carapace coarsely sculptured. 

Type: Chelone ornatus Leidy. 

In 1882 (Proc. Amer. Philos. Soc, xx, p. 144) and again in 1884 (Vert. Tert. Form. 
West, p. 112) Cope characterized this genus as having 9 pairs of costals, 2 anterior peripherals 
joined to the costals, and a high dorsal keel. It is now evident that he had derived his mfor- 
mation from a carapace sent to him by Dr. George Little, at one time State Geologist ot 
Georgia (Amer. Naturalist, ni, 1878, p. 129). 
14 



210 FOSSIL TURTLES OF NORTH AMERICA. 

Cope arranged this genus among his Propleuridae. The cordate form of the carapace 
in the state collection at Atlanta, deeply excavated in front and pointed behind, appears to 
indicate close relations with the Cheloniidae, and to this family the species is here provisionally 
assigned. 

Peritresius ornatus (Leidy). 

Chelone ornatus, Leidy, Proc. Acad. Nat. Sci. Phila. 1856, p. 303; Smithson. Contrib. Knowl., xiv, 

1865, pp. 105, 119, plate xviii, fig. 10. 
Peritresius ornatus, CoPE, Cook's Geol. Nays' Jersey, 1868 (1869), p. 735; Amer. Naturalist, III, 1869, 

p. 88; Ext. Batrach., Reptilia, Aves N. A., 1870, p. 150; Vert. Cret. Form. West, 1875, p. 260; 

Amer. Naturalist, 111, 878, p. 129. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 

This is yet an imperfectly known species. It was based by Leidy on conjoined portions 
of two lateral peripherals, which had been found in Cretaceous greensand in Burlington 
County, New Jersey. This greensand probably, but not certainly, belonged to the upper 
bed. The bones are probably now in the collection of the Philadelphia Academy, but they 
have not been seen by the present writer. They were described by Leidy as measuring an 
inch and a half in breadth and as being wedge-shaped in section. The outer border was 
acute; the inner border grooved, and eight lines, about 17 mm., high. Both the upper and the 
lower surfaces were coarsely, but beautifully, tuberculated, and the tubercles showed a tendency 
toward a radiate arrangement. Some of the tubercles at the ends of the peripherals are 
lengthened out into ridges. Cope states that there were no indications of dermal sulci on the 
bones. He mentions also a costal which he thought belonged at least to the genus. 

Under the species Taphrosphys nodosus the present writer has suggested that it may be 
identical with the species here described. 

In the collection of the Geological Survey of Georgia is the greater portion of the carapace 
of what appears to have been a large sea-turtle. This specimen was at one time in the hands 
of Prof. E. D. Cope and was by him identified as Peritresius ornatus Leidy (Amer. Naturalist 
III, 1878, p. 129). Considering the facts that Leidy's type consisted of portions of two 
evidently hinder peripherals and that all the hinder peripherals of the Georgia specimen are 
wanting we can not be sure that the identification is correct. For the present it may be allowed 
to stand. Undoubtedly it was on this specimen that Cope based his definition of the genus 
Peritresius. It is not known why Cope concluded that there were 9 pairs of costals. 

The specimen here described was found by Mr. Loughridge, of the Georgia Geological 
Survey, then under the direction of Dr. George Little, in the Ripley formation of the Upper 
Cretaceous, on Bonnahachee Creek, Stewart County, Georgia. It presents most of the carapace, 
but unfortunately the left side is yet concealed by a mass of matrix. This has prevented an 
accurate study of the specimen and the production of a figure. The length of the portion pres- 
ent is 675 mm. in a straight line, 735 mm. over the curve. The original length of the carapace 
must have been about 900 mm. In form the carapace is cordate, like that o( Caretta. Anteriorly 
there is an excavation in the border 200 mm. wide and about 30 mm. deep. The free border is 
obtuse and the bone is about 16 mm. thick. The costals are about 8 mm. thick. The anterior 
peripherals are suturally joined to the first costals. Behind this they are missing; but it is 
evident that some of them were connected with the costals only by gomphosis of the ribs. 

The most conspicuous feature of the carapace is the great dorsal keel. This begins on the 
nuchal bone and continues to the rear of the carapace. It is thick and obtuse on the anterior 
half of the carapace. Here the sloping sides of the keel are very steep, the summit is obtuse, 
and the height is about 36 mm. Posteriorly the summit is more acute. 

On account of the great number of fractures it is difficult to follow the sutures. Where 
observed these are coarse and zigzag. A few of the sulci are traceable. The third vertebral 
scute has a width of about 125 mm. The sulci forming its lateral boundaries are nearly parallel 
with the axis of the animal. 

The whole upper surface of the carapace is coarsely pitted and ridged, much like that of 
some species of Trionychidae. 5 or 6 ridges are usually to be counted in a line 25 mm. long. 

The anterior border of a second specimen is in the same collection. Found with it is the 
greater portion of the united dentary bones. The triturating surfaces are flat. The length 
of the symphysis is 53 mm. 



CHELONIIDii;. 211 

The writer has been permitted to examine these specimens thru the courtesy of the 
present state geologist, Prof. WilHam S. Yeates. 

In the American Museum of Natural History is a small collection of bones, without indi- 
cation of origin, but which are provisionally assigned to the present species. The number of 
the lot is 1410. They are a part of the Cope collection and evidently were found in New Jersey. 
These bones are filled with iron pyrites and they are black, with some surface stain of chocolate. 
One fragment is that of a costal. The sutural border is 12 mm. thick, but thru the rib 
the thickness is 17 mm. The upper surface is covered with coarse ridges and tubercles, irregular 
in size and arrangement. They resemble greatly those of Arnyda •uirgtniana illustrated on 
plate 96, figs. 7, 8. Another fragment appears to be the upper end of a costal, with the base 
of the rib-head. The thickness varies from 7 mm. to 10 mm. The fragment is 75 mm. wide. 
Another piece seems to be a part of a peripheral, showing the acute free border, but not extend- 
ing to the costal border. The length of the fragment is 56 mm.; the width, 63 mm.; the thick- 
ness of the upper border, 21 mm. The upper surface is convex from the free border upward, 
while the lower surface is concave. One end appears to have come close to the suture, and 
here the tubercles run at right angles with the suture. Those at the outer end are small and less 
elongated. Between the two regions are some ridges running at right angles with the free border. 

Three fragments belong to the plastron. The best of these resembles the outer end of the 
left hyoplastron of the loggerhead. The fragment is 135 mm. long, 67 mm. wide, and 20 mm. 
thick at the proximal end. Toward the outer end the bone thins and ends in a number of 
digitations. The border, supposed to be axillary, is concave in outline, with the edge obtuse 
near the digitations, but subacute more proximally. The supposed hinder border evidently 
articulated with another bone, probably the hypoplastron, out nearly to the digitated border, 
thus abolishing the fontanel. The greater part of the inferior surface of the bone is orna- 
mented with anastamosing ridges and some tubercles, about three or four of them lying along 
a line 20 mm. long. 

Genus SYLLOMUS Cope. 

Costal bones suturally articulated with the peripherals. Surface of carapace sculptured 
with grooves and ridges. Humerus much flattened distally. Ectepicondylar passage a com- 
plete foramen. Radial process remote from head of bone. 

Type : Syllomus crispatus Cope. 

Syllomus crispatus Cope. 
Plate 32, figs. I, 2; teit-fig. 269. 
Syllomus crispatus. Cope, Proc. Amer. Philos. Soc, xxxv, 1896, p. 139.— Hay, Bibliog. and Cat. Foss. 

Vert. N. A., 1902, p. 442. 

The remains on which this species was based are now in the American Museum of Natural 
History and bear the number 6134. These remains consist of the right humerus, lacking only 
the ulnar process, and 2 fragments of costals. These were collected by Cope in Miocene 
deposits, on the Pamunkey River, Virginia. 

The first fragment of costal belongs to the distal end of the bone (plate 32, fig. i). The 
width at the end is 47 mm., but this diminishes proximally. The thickness at the proximal 
end of the fragment is 6 mm.; but at the distal end this has become only 2 mm. This border 
articulated by close suture with the contiguous peripheral. Doubtless the rib passed beyond 
the border and entered a pit in the peripheral. The surface of the bone is sculptured with 
anastomosing grooves and ridges, usually parallel with the long axis of the costal. The sculp- 
ture becomes coarser toward the proximal end of the bone. Parallel with and close to the 
peripheral border is a shallow groove which may be a portion of a costo-peripheral sulcus. 

The other fragment of costal comes from near the neural end (plate 32, fig. 2) and the 
width is 45 mm. It is crost by a narrow, but sharp, ridge, which indicates that the carapace 
was traverst on each side by a lateral keel. We may also safely assume that there was a median 
keel The thickness of the bone, on what is probably the proximal side of the keel, is 7 mm. 
Toward the distal end the thickness diminishes. The surface of this fragment is more coarsely 
and irregularly sculptured than that of the other and the elevations vary more in size and form. 
No trace of sulci appears on this fragment. A portion of the surface is, however, destroyed. 



212 



KOSSH, TURTLES OF NORTH AMERICA. 





The humerus (fig. 269) resembles that of a true sea-turtle. The total length is loomm. The 
distal end is broad and flat. The head of the bone is elongated reniform, the long axis being 
at nearly right angles with the plane of the distal end. Its long diameter is 32 mm.; the 

shorter, 17 mm. The ulnar process is broken away, 
but a groove separated it distinctly from the head. 
The radial process is divided into two portions; one 
part being on the under side of the shaft, 40 mm. 
below the upper border of the head; the other part 
on the radial border, still further down on the shaft. 
Both portions are prominent. The narrowest part 
of the shaft is 20 mm. wide and 1 1 mm. thick. The 
distal end is 41 mm. wide. The ectepicondylar pas- 
sage is a foramen. It emerges on the lower side 
of the bone 10 mm. above the distal extremity. 
The condyles are distinctly separated from the sur- 
rounding bone. Their fore-and-aft extent is 22 mm. 
The radial epicondyle is broad, thick, and flat; the 
ulnar little prominent. It is remarkable that Cope 
in his description of this bone regarded the anterior 
border as the posterior. 

Genus LEMBONAX Cope. 

Fig. 26g.~Syllomus cnspatus. Right Plastron with probably a fontanel extending 

humerus Type. xi^. from the entoplastron to the xiphiplastra. No 

„ , , , , , • 1 L J- .u J dieitations of bone proceeding from the plastral 

On left, the ventral surface; on right, the radial border. » \, t- • , r i i 

bones toward the midUne. Lpiplastrahrmly sutured 
to the hyoplastra, the suture oblique to the midline; the xiphiplastra similarly joined to the 
hypoplastra, the suture at right angles with the midline. 
Type: Lembonax polemtcus Cope. 

The position of this genus is very problematical. Cope concluded originally that the 
relationships were with the Chelydridx rather than with the Cheloniidae. At a later time he 
stated (Amer. Naturalist, xvi, 1882, p. 989) that not enough was yet known to assure us to 
what family the genus belonged, except that they were not Trionychidae. Nothing has been 
added to our knowledge on that point since that time. Cope referred two additional species, 
L. propylaus and L. insularts, to the genu?. While the present writer retains these species 
in this genus provisionally, there appears to be no evidence whatever that they belong there. 

For want of knowledge where Lembonax polemtcus belongs it is here referred to the 
Cheloniidae. 

Lembonax polemicus Cope. 

Fig. 270. 

Lembonax polemicus, CoPE, f^xt. Batrach., Reptilia, Aves N. A., 1870, p. 168. — Hay, Bibliog. and 
Cat. Foss. Vert. N. A., 1902, p. 444. 

This species was sent to Professor Cope from the Eocene greensand near Farmingdale, 
Monmouth County, New Jersey. The type and only known specimen is now in the American 
Museum of Natural History and bears the number 11 34. It furnishes a portion of the plastron 
and the base of the scapula. The materials indicate a large individual, but they furnish 
meager information regarding its structure and relationships. 

The most important parts of the plastron are a portion of the right hyoplastron and a 
portion of the right hypoplastron. The outer borders of both these bones are wanting. 

The hyoplastral fragment (fig. 270) has at present a length of 233 mm., having apparently 
lost a slight portion since it was studied by Cope. The greatest width is 136 mm. The thick- 
ness varies from 10 to 15 mm. Anteriorly the bone terminates at the union with the epi- 
plastron. Posteriorly, there is no indication of suture with the hypoplastron, and this may 
have been farther away than indicated in the figure. The inner border of the bone is thick, 



CHEI-ONIID^. 



213 



obtuse, and along the hinder third is somewhat dentated. Anteriorly, the upper surface is 
furnisht with ridges which are sharp and prominent as they approach the free inner border, 
but which become obsolete in the opposite direction. These ridges seem to diverge from the 

anterior buttress of the hyoplastron (fig. 270, C), if such 
existed. At the anterior end of the bone the inner border 
turns slightly outward and, at an angle of about 75°, meets 
the sutural border for articulation with the epiplastron (fig. 
270, A to B). These bones were not joined by squamosal 
suture, as they are in the Cheloniidx and the Chelydridae, 
but by dentated suture. The lower surface of the bone is 
smooth and convex, especially transversely. The upper 
surface is concave. At the anterior end of the bone, on 
the upper surface, 190 mm. behind the anterior end (fig. 
270, C), is a slight elevation, as if it were the base of an 
axillary buttress. The lower surface of the bone just behind 
this point also indicates that the plastron rose toward the 
carapace. 

The portion of hypoplastron has a length of 155 mm. 
and a width of 125 mm. Anteriorly the suture for the hyo- 
plastron is missing. The inner border is subacute and 
smooth, thus differing from the corresponding border of the 
hyoplastron. The suture for the xiphiplastron runs at right 
angles with the midline. It shows that the two bones were 
firmly united by coarse interdigitating teeth. Toward the 
outer border the bone has a thickness of about 13 mm., 
but this diminishes slowly toward the inner border. As the 
outer border is approacht, the bone begins to ascend in a 
decided manner, as if approaching the carapace (fig. 270, 
/)). If this conclusion is correct, as indicated by both hyo- 
plastron and hypoplastron, these bones were, relatively to 
their length, very narrow; and there is indicated a wide fonta- 
nel, that extended from the entoplastron to the xiphiplastra. 
It seems improbable that the inner borders came into close 
proximity. There were certainly no digitations extending 
from the hyoplastron and hypoplastron toward the mid- 
line, as there are in the Cheloniidx and the Chelydrids. 
A fragment of bone present indicates that the hyohypo- 
plastral suture was formed by the interdigitation of finer 
processes than that of the hypoxiphiplastral suture. On the anterior end of the fragment of 
hypoplastron there are traces of this suture, so that this bone appears to have had a fore- 
and-aft extent of about 170 mm. 

The fragment of scapula present was that of a very large turtle. It is possible that it did 
not belong to the same individual as the plastral bones. The long diameter of the neck of 
the bone is 98 mm.; the short diameter, 42 mm. 




Fig. 270. — Lembon a X polemicus. 
Portion of plastron. Type. X}. 
No. 1134 A. M. N. H. 

A to B, border for articulation with the epi- 
plastron ; C, base of axillary buttress ; 
D, probable base of inguinal buttress ; 
hya, hyoplastron; hypo, hypoplastron. 



Lembonax? insularis Cope. 
Fig. 271. 



16. — Hay, Bibliog. and Cat. Kos.s. 



Lembonax insularis. Cope, Proc. Acad. Nat. Sci. Phila. 1872, p. 

Vert. N. A., 1902, p. 444- 

Professor Cope's materials representing this species were meager and his descriptions of 
it unsatisfactory. Nor have the means for increasing our knowledge of it been augmented; 
they have even been reduced. In the American Museum of Natural History there is a lot of 
bones labeled by Cope as the type of his Lembonax insularis, and bearing the museum s 
number 2347. This lot came to Cope from the Eocene bed of greensand at Vincentown 
Burlington County, New Jersey. Cope stated that the species was based on nuchal and 



214 



FOSSIL TURTLES OF NORTH AMERICA. 




peripheral bones ; but he also exprest doubt whether these bones might not rather belong 
to the rear of the carapace. Among the bones in the lot mentioned there is none that can be 
recognized as a bone belonging in the midline. Fragments are found which, when fitted 
together, furnish fig. 271. The bone markt by I is certainly that called by Cope the first 
marginal. It seems impossible to determine just where it belonged. It is, for various reasons, 
improbable that it belonged in front. Hence, assuming that Cope had a symmetrical bone 
which joined the supposed first peripheral, the latter is here taken to belong behind and to 
be the last left peripheral. 

Cope estimated the length of the bone i to be 153 mm. It is not known whether he took 
account of the narrow fragment on the right of the figure; but there is no doubt that this 

fragment belongs where it is placed. 
The length of the bone then, not includ- 
ing a deeper plate on the right that 
would be hidden when the bone joined 
the one next to it, is 165 mm. The 
greatest width, omitting a deep sutural 
plate, is 100 mm. The thickness on the 
right side is 27 mm. The greatest thick- 
ness is to the left of the middle of the 
length and is 45 mm. Cope states that 
this is the thickness nearthesutureof the 
second peripheral; from which expres- 
sion we may infer that the narrow frag- 
ment on the left of the figure, markt 2, 
is a part of the penultimate peripheral. 
The free border of the bone I, so far as 
represented, is thick and obtuse. Fig. 
Fig. 271.— Lembortax insularis. Fragments of two bones -^ ^ stciwn from a to b. The free 

of the carapace, with section of one. Type. X J. ^^^^^^ ^^ ^^^^ ^^^^^^^ ^^^ left, projected 

a to b, direction of section, i, probable last peripheral; in an obtUSe angle. It appears improb- 

2, probable penultimate peripheral. ^j^,^ ^^^^ ^^^^ ^^ irregular border 

would be found on the front of the carapace. The upper surface is convex and undulating, 
but there is no definite sculpture. Toward the free border the surface is pitted and rough. 

Seen from below the bone is concave. Near the hinder border of the narrow fragment on 
the right is a prominent ridge. A suspicion is awakened that this is the fragment which Cope 
mentions as bearing the support of a vertebra. The ridge mentioned continues for some 
distance on the larger part of the bone of which the fragment is a part. Behind it, on the 
larger fragment, are two equally prominent ridges, followed by some smaller ones, and these 
are separated by deep grooves. What is the meaning of these grooves and ridges can not be 
determined. It is possible that the median bone, whether nuchal or pygal, sent a process 
along the under surface of the bone i, two-thirds its length. 

The bone shown on the left of the one indicated by i has a thickness of 33 mm.; and it 
is possible that this is a part of what Cope called the nuchal. In that case the bone i would 
be either the right ultimate peripheral, or first left peripheral. 

As in the case of L.? propylaus, it is impossible to state with certainty that this species 
belongs to the genus Lembonax. 

Lembonax? propylaeus Cope. 
Fig. 272. 

Lembonax propylceus. Cope, Proc. Acad. Nat. Sci., Phila. 1872, p. 15. 
Lembonax prophylaus. Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 444. 

The type of this species is now in the American Museum of Natural History, and has 
received the number 13 10. This specimen was found in the Eocene greensand, in the vicinity 
of Farmingdale, Monmouth County, New Jersey, the same formation and locality that furnisht 
the type of the genus, L. polcmicus. 



CHELONIlDiE. 



215 



The type specimen (fig. 272), all that is known of the species, consists of a nuchal bone, a 
considerable part of the first left peripheral, and a fragment of the right. 

The species is remarkable on account of the great excavation in the front of the nuchal, 
reminding us of that of the nuchal of Allopleuron hoffmani (Gray). The individual was a 
large one, the distance between the extremities of the nuchal being about 225 mm. The antero- 
posterior extent of the bone, at the midline, is 105 mm. The thickness on the midline and half- 
way between the fore and hinder borders is 25 mm. The anterior border is subacute, except 
toward the extremities, where it becomes thick and obtuse. In the hinder border there is a 
notch for the front end of the first neural bone. 

The border for union with the first peripheral is beveled, so that the first peripheral some- 
what overlaps the nuchal. The suture between the two bones is a coarse one. A portion of 
the border for union with the first costal presents a kind of tongue-and-groove joint, there being 
on the edge of the nuchal 2 grooves and 3 slightly projecting laminae. 

The upper surface of the bone is smooth and there are no traces seen of the presence of 
sulci. On the under side of the bone, there is, on the midline near the hinder border, an eleva- 




FlG 272 — Lembonax propylicus. Nuchal and portions of right and left first peripherals. 

Type. Xi 

tion that probably furnisht an articulation for the neural spine of the first dorsal vertebra. 
There is no surface for articulation with the last cervical, such as is found in the living 

Cheloniidae. 

Cope referred this species unqualifiedly to the genus Lembonax and stated that it threw 
much light on the character of the genus. As there are no carapacial bones accompanying the 
type of L. polemicus and no plastral bones accompanying the type of his L. propylceus, it is 
difficult to understand why they should be so confidently referred to the same genus. On the 
other hand, it is possible that both types belong to the same species. 

Genus PROCOLPOCHELYS nov. 

An imperfectly known genus of Cheloniidae. Shell large, with thick and heavy neurals and 
costals; two or three pairs of costals articulating each with 3 neurals. The neurals probably 
exceeding 8 in number. First costal plate of each side suturally articulated with the nuchal 
and the first peripheral; its rib-end entering pit in third peripheral. Large fontanels between 
the costals and all the peripherals behind the first. 

Type: Chelonta grandteva Leidy. 

The known materials of the type of this genus lack much of yielding a satisfactory knowl- 
edge of the characters of the genus. Nevertheless, it seems evident that Leidy's species does 
not belong to the same genus as Chelonia mydas. Cope referred the species to his genus 
Puppigerus; but, inasmuch as Lydekker in 1889 (Cat. Foss. Reptilia, m, p. 52) made Chelonc 



2l6 



FOSSIL TURTLES OF NORTH AMERICA. 



longiceps the type of Puppigerus, and the latter is not congeneric with Chelonia grandava, this 
species can not be placed under Piippigerus. 

A study of the known materials of Chelonia grandceva makes it apparent that the first 
costal bone was articulated with the nuchal and the first peripheral of each side and that some 
of the costals were articulated proximally with 3 neurals each. In these respects the species 
differs from any belonging to either Chelonia, Eretmochelys, or Caretta. 

As regards the relations of the costals to the neurals, we find similar conditions in a spec- 
imen of Colpochelys kempi in the American Museum of Natural History. In this there are 
apparently 13 neurals, and the costals of the third, fourth, fifth and sixth pairs articulate each 
with 3 of these neurals. Nevertheless, nearly all the neurals are hexagonal, none octagonal, 
as in Testudo, where some costals articulate with 3 neurals. 

On a comparison of the widths of the costals with the lengths of the neurals we find a 
confirmation of the conclusion that there were, as in Colpochelys, more than 8 neurals. 

But while agreeing with Colpochelys in these respects Procolpochelys differs from it in 
another. In Colpochelys the end of the rib of the first costal bone enters a pit in the fourth 
or fifth peripheral, while in Procolpochelys grandceva, as in most Cheloniidae, the end of the 
first costal rib enters a pit in the third peripheral. 

Procolpochelys is therefore distinguisht from all the hitherto recognized genera ot Che- 
loniidae. 

On pages 8, 9, and 10 Colpochelys kempt has been referredj to [the] genus Lepidochelys. 




Figs. 273 and 274. — Procolpochelys grandteva. Neurals. X'j. 
273. Two neural bones. Type. 274. Neural. No. 1027 A. M. N. H. 

Procolpochelys grandaeva (Leidy). 
Figs. 273-280. 

Chelonia grandteva, Leidy, Proc. Acad. Nat. Sci. Phila., v, 1851, p. 329; Ibid., viii, 1856, p. 303. — 
Cope, Cook's Gaol. New Jersey, 1868 (1869), p. 738; Ext. Batrach., Reptilia, and Aves N. A., 
1870, p. 153, figs. 40, 41. — Maack, Palaeontographica, xviii, 1869, p. 283. 

Puppigerus grandievus. Cope, Ext. Batrach., etc., 1870, p. 235; Proc. Amer. Philos. Soc, xiv, 1875, P- 
363. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 443. 

Dr. Leidy's Chelonia grandceva is an insufficiently known species. The type belongs to 
the Philadelphia Academy. It consists of three neural bones which had been found in what 
is regarded as Miocene marl, in Salem County, New Jersey. One of these neurals appeared 
to Leidy to be the first. A portion of the anterior end had been broken off, yet the part 
that remained was 67 mm. long and 48 mm. wide. The other two neurals were hexagonal, 
as wide as long or wider, and each had a posterior process, showing that some of the neurals 
were sharply notcht in front. One of these (fig. 273, a) was 54 mm. long, 67 mm. wide, and 
15.5 mm. thick; the other (fig. 273, i) was 58 mm. long, including the process, and 58 mm. wide. 

Cope, in 1870, as cited, further described the species. He had some fragments of costals; 
a fragment of probably the nuchal; the scapula, which he figured; and what he described as 
the femur, but which was evidently the humerus, as indeed he says it was in his explanation 



CHELONIID^. 217 

of the figures on page ii. These came from Shiloh, Cumberland County, New Jersey. These 
specimens are now in the American Museum and have the number 1319. The scapula re- 
sembles that of Caretta, except that the upper end is more flattened. The humerus is now 
missing from this lot of bones. The radial process is stated to have been on the shaft some 
distance below the head. The costal plate is 82 mm. wide and 13 mm. thick. This and other 
fragments of the costals show that these bones were not suturally joined to the peripherals; 
but also that there was no considerable interval between them, the projection of the rib being 
short. With this lot is the "nuchal or marginal vertebral" mentioned by Cope. It appears to 
be the left end of the nuchal. The thickness at the median end of the fragment is 15 mm., 
that near the junction with the first costal, 21 mm. The first peripheral sent a thin process for 
some distance beneath the nuchal, near the anterior border. 

Cope mentions another specimen, belonging to the Philadelphia Academy, which presented 
4 peripherals and a fragment of a hypoplastral. A peripheral, believed to be the third, had a 
length of about 47 mm., and a width of 21 mm. Cope concluded that the rib of the first costal 
did not run parallel with the hinder border of the costal, but approacht the hinder border 
toward the distal end. Another peripheral belonging near the middle of the series was trigonal 
in section, measuring 59 mm. across the lower face and 45 mm. across the inner, or visceral, 
face. This and two other peripherals were emarginate at the middle of the outer border. The 
dermal sulcus crost the peripherals a little behind the middle. 

In the American Museum of Natural History is a lot of fragments labeled by Cope 
as belonging to this species. The catalog number is 1027; the locality uncertain, but probably 
in New Jersey. A neural appears to confirm Cope's determination. This neural (fig. 274) is 
63 mm. long, in the midline of the upper surface and including the process. The width is 
71 mm.; the thickness, 16 mm. The anterior border is beveled so that the neural was overlapt 
somewhat by the preceding neural; and the hinder border similarly overlapt the succeeding 
one. A peripheral, probably the second, is 85 mm. long, 47 mm. wide at the middle of the 
length, and 20 mm. thick. The outer border is obtuse; the inner, acute (fig. 275). Frag- 
ments of three other peripherals belonged probably near the rear of the carapace; at least, 
they have a much narrower visceral face than those described by Cope. One has the upper 
and lower faces 48 mm. wide; the inner face only 19 mm. The other bones throw little 
or no additional light on the species. 

In the paleontological collection at Princeton University is a lot of turtle bones that are 
labeled as having been received in December, 1879, from Mr. George Erety Shoemaker, now 
of Philadelphia. This gentleman writes that these remains came from a marl bed near Shiloh, 
Cumberland County, New Jersey. This marl belongs to the Miocene. While there is a large 
amount of this material, it unfortunately consists of the remains of at least four turtles, belong- 
ing apparently to 2 genera. It has been found impracticable to separate these satisfactorily, 
but apparently there are parts of 3 individuals of the present species. 

With these bones are 2 neurals which, it can hardly be doubted, belong to P. grandccva. 
One of these is 50 mm. long, with a short posterior spine, 48 mm. wide, and 12 mm. thick. 
To it is attacht the neural arch. Another, a more posterior and smaller one, is 32 mm. long 
and 44 mm. wide. Two other neurals present are only 8 mm. thick and evidently belong to 
a quite different turtle. 

There are in the lot, belonging apparently to P. grandava, at least five proximal ends of 
costals, and most of these show that they articulated each with three neurals, of which the 
median one was the smaller. These costals vary in width from 80 mm. to 105 mm. and in 
thickness from 10 mm. to 14 mm. The rib-heads were large. Besides the proximal ends of 
costals, there are many other portions of these bones. A part of a right first costal requires 
description. The proximal end is missing. Near the distal end the width is no mm.; the 
thickness 12 mm. The anterior border articulated with the nuchal and with the first periph- 
eral, the two sutural borders making between them an angle of about 135°. The remainder 
of the distal border, 65 mm., was free from the adjacent peripheral, the second. Near the 
hinder border issues the rib, making its way to the pit in the third peripheral. Only a portion 
of the second costal has been recognized. Another costal, prob^-bly the fourth, is represented 
by the distal two-thirds. The distal end is 133 mm. wide; the other extremity, \ 1 1 mm. The 
thickness, at a distance of 85 mm. above the free border, is 18 mm.; but at the proximal end 



2l8 



FOSSIL TURTLES OF NORTH AMERICA. 



oi" the fragment, only 12 mm. The sutures are very jagged. Nearer one sutural border a 
sulcus descends, which separated two costal scutes. Two other costals measure each 72 mm. in 
width at the distal end. In all these the free end of the rib projected beyond the distal border. 

A nuchal is represented by the greater part including the entire front. There was an 
articular tuberosity for the eighth cervical; the anterior border of this bone was 200 mm. 
long. It is excavated somewhat for the neck and head. The upper surface is quite convex 
from side to side. Antero-posteriorly the bone measures 96 mm. The front border is obtuse; 
behind it a short distance the thickness is 16 mm., increasing at the ends of the bone to 20 mm. 
The hinder border joined suturally the first costal bone. 

The first left peripheral is connected with the nuchal. It is 1 10 mm. long and 80 mm. 
wide. The hinder border articulated with the first costal. The free border is obtuse and the 
distal end is 18 mm. thick. There is present the proximal end of another left first peripheral 
which is considerably thicker than the one just described. 

What are evidently right and left second peripherals, of an individual smaller than either 
of the above, are present. The proximal end of the one of the left side is 65 mm. wide, whereas 
the distal end of the left first, described above, is 72 mm. wide; besides, the two do not fit 




Figs. 275-280. — Procolpochelys grand<eva. Various peripherals. X§. 

275. Section across middle of supposed second peripheral; free border toward 

right. No. 1027 A.M.N. H. 

276. Section at anterior end of second peripheral. Princeton Univ. Coll. 

277. Section near hinder end of third peripheral. Princeton Univ. Coll. 

278. Section near front end of supposed fifth peripheral. Princeton Univ. Coll. 

279. Right hinder peripheral, view above. Princeton Univ. Coll. 

280. Upper surface of supposed eleventh peripheral. Princeton Univ. Coll. 

together as they should if they belonged to the same individual. No differences are seen 
that indicate different species. This second peripheral (fig. 276) is 95 mm. long, 64 mm. 
wide and 22 mm. thick proximally; 51 mm. wide and 25 mm. thick distally. The anterior 
border is obtuse, the hinder acute and with suture for a costal. The succeeding, or third, 
peripherals are joined to those just described. They measure about 95 mm. along the free 
border and are 70 mm. wide at the distal end. A ridge that begins on the inferior surface of 
the second becomes more conspicuous near the outer border of the anterior half of the third; 
and just above it, near the front of the bone, is the pit for the rib of the first costal. Fig. 277 
is a section at the hinder end of this peripheral. 

There are present nineteen peripherals, not counting the part of a first which belongs to 
the larger individual. At least three are not at all represented; but at least two that are 



CHELONIID^. 219 

present on one side are not represented by their fellows of the opposite side. There is therefore 
both a redundancy and a shortage. Evidently neither fourth peripheral is present. There 
are representatives of 3 peripherals, probably the fifth, sixth, and seventh of the left side. 
The supposed fifth (fig. 278) is 99 mm. long and consists of two plates which meet each other 
at an acute free border. The two succeeding this, the sixth and the seventh, are damaged, 
but the faces make a smaller angle with each other. The fifth presents an extremely shallow 
rib-pit, located in the hinder half of the length. It is highly probable that these peripherals 
belong to a turtle of some other genus. 

On the left side are three peripherals following in their natural order. Each of these 
has three faces, a somewhat convex upper face, a flat lower face, and a channeled visceral 
face. The rib-pit of the first one is a little behind the middle of the length. This bone 
resembles one in lot number 2215, of the American Museum mentioned above; but both sides 
of the latter are flat. The bone under description is 125 mm. long, 64 mm. wide in front, and 
22 mm. thick. The next one is a very little shorter and slightly narrower. It presents no pit. 
This is in the front end of the next peripheral, close to the suture. This next bone is 1 15 mm. 
long, 46 mm. wide anteriorly and 21 mm. thick. In general, the section of it resembles that 
of the first of the three here described. Bones corresponding to the second and third of those 
just described appear to be represented on the right side of the animal. On this side the pit 
which was in the front end of this third of the side is moved forward to the left junction between 
the two bones. On this side, too, the hinder of the two is broken, but both ends of it appear 
to be present. Following what almost certainly is its hinder end is a similar peripheral, with 
its hinder end missing. This bone has a small pit for a rib. The inner, or visceral face, is 21 
mm. wide. 

Besides these peripherals there are four others present which require consideration. Two 
of these are corresponding bones of opposite sides. Fig. 279 represents the one taken to 
belong to the right side. It will be observed that there is a decided change in the direction 
of the curve at the supposed anterior end. This bone is 88 mm. long and 48 mm. wide at the 
sulcus. On its channeled inner face, at the end of the sulcus, is a deep pit for a rib. A portion 
of another peripheral is attacht to what is supposed to be the anterior end of this curved 
peripheral. Its inner face is narrower. 

The curved peripheral of the other side has, at some period of life, had the supposed 
anterior end damaged, so that it has the appearance of having formed a false joint with its 
contiguous peripheral. Attacht to the hinder end of this bone is another peripheral (fig. 280) 
whose fellow is not present. It is 105 mm. long. The inner face is channeled but there is 
no pit. One end, supposed to be the posterior, is narrow — only 24 mm. wide. It is probable 
that this bone is the eleventh and that the narrow end joined the pygal. 

To add to the difficulties, there is present what appears to be the left half of a pygal bone. 
This was 86 mm. wide and 65 mm. high. It articulated suturally with a suprapygal and 
laterally by its whole height with the contiguous peripherals, the eleventh pair; but certainly 
not with the one regarded above as the eleventh. 

Portions of a large thick plastron are present. One piece may be part of a hyoplastron. 
A free border, probably the outer, is digitated. One border articulated suturally with another 
bone, supposedly the hypoplastron. 

On the nuchal bone the sulcus bounding posteriorly the nuchal scute or the first marginal 
is 44 mm. behind the free border, near the midline and 54 mm. from the border at the outer 
end of the bone. The limits of the nuchal scute can not be made out. On the first and second 
peripherals the costo-marginal sulcus is seen running nearer the costal margins of the bones 
than the free margins. Posterior to these the costo-marginal sulci doubtless lay on the mtervals 
between the costal and peripheral bones. Each peripheral is crost by a sulcus separatmg 
two marginals. 

The outer surfaces of all the bones are smooth, except that they are markt by numerous 
vascular grooves. 

In the paleontological collection at Rutgers College, New Brunswick, New Jersey, are 
found one peripheral and one complete costal which are labeled as belonging to this species 
and as having come from the Miocene marl at Tinton Falls. There is probably an error in 
the locality. 



220 FOSSIL TURTLES OF NORTH AMERICA. 

The peripheral appears to be the second of the series. Its length is Ii6 mm.; its greatest 
width, 66 mm.; and the thickness, 22 mm. This is reduced gradually to the acute hinder 
border. The anterior border is obtuse. 

The length of" the costal, omitting the portion of the rib projecting from the peripheral 
border, is 220 mm. The width is 87 mm.; the thickness 1 1 mm. at the proximal end, 14 mm. 
distally. Proximally the costal articulated with 3 peripherals, as we have found to be the case 
with some of the costals of the Princeton specimen. The middle and smallest of these neurals 
was crost by a sulcus which divided two vertebral scutes. This sulcus is 36 mm. long on the 
costal, a fact that indicates that the vertebral scutes were not wide. 

The surface of the bone is smooth, but markt by vascular grooves. The distal border was 
not articulated to the peripherals, except by gomphosis of the end ot the rib. 

Genus CHELONIA Brongniart. 

Cheloniidae with persisting costo-peripheral fontanels; four pairs of costal scutes; jaws not 
hookt; the grinding-surface of each maxilla with a prominent tuberculated ridge which 
terminates in front in a sharp tooth and which does not extend on the narrow premaxilla. 
Limbs each usually with a single claw. 

Type: Chelonia mydas (Linnaeus). 

To this genus there is assigned, with doubt, a single species of North American fossil 
turtles. It is that called by Cope Puppigerus parvitectus. In the writer's Bibliography and 
Catalogue, 1902, p. 443, this species and Leidy's Chelonia grandxva were catalogged under 
the genus Puppigerus; and he would be glad to retain them there were it possible. In that 
work it was stated that the type oi Puppigerus was Leidy's Chelonia grandceva; but the fact 
was overlookt that Mr. Richard Lydekker had, in 1889, chosen as the type of that genus Owen's 
Chelone longiceps. According to Lydekker, Puppigerus becomes a synonym o{ Lytoloma Cope. 
It is possible that such is the case; but it appears more probable that Puppigerus is a distinct 
genus, with P. longiceps as its type. The writer can not believe that Leidy's C. grandccva 
is congeneric with P. longiceps and he has for that reason proposed for C. grandccva the generic 
name Procolpochelys. Furthermore it is improbable that parvitecta belongs in the same genus 
as Leidy's grandccva. 

About the only reasons for placing the species parvitecta under Chelonia are that we thus 
avoid erecting a new genus on extremely insufficient materials and that we return the species 
to the genus to which it was originally referred, which genus is probably not far from the true 
one yet to be establisht. 

On page 143 of the Proceedings of the Philadelphia Academy for 1867, Cope described 
fragments of what he regarded as two species of Chelone; but he applied no specific names to 
these. In the Miocene volume of the Maryland Geological Survey, 1904, page 63, Case has 
copied Cope's descriptions. Case has also described and figured (op. cit., p. 64, plate xxvi, 
fig. 5) the proximal portion of a scapula which he refers to an unnamed species of Chelone. 
This, as well as Cope's specimens, was found in the Calvert formation of the Miocene. These 
remains are not generically determinable. 

Chelonia? parvitecta Cope. 
Plate 32, fig. 3. 

Chelone parvitecta. Cope, Ext. Batrach., Reptilia, Aves N. A., 1870, p. 155. 

Chelone parviscuttim, CoPE, Cook's Geol. New Jersey, 1868 (1869), p. 738. 

Chelone parviscutatus, CoPE, Amer. Jour. Sci. (2), I, 1870, p. 138. 

Puppigerus? parviscutum, CoPE, Ext. Batrach., Reptilia, Aves N. A., 1870, p. 235, 244. 

Puppigerus parvitecta, CoPE, Proc. Acad. Nat. Sci., 1872, p. 15. 

Puppigerus parvitectus. Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 443. 

The present species, whose specific name has been so greatly abused, has as its type a 
single costal plate, which is now in the American Museum of Natural History and bears the 
number 1318. It was found at Squankum, Monmouth County, New Jersey, and was supposed 
by Cope to have come from the Miocene marl; but this is Lower Eocene. He reported having 
found another costal in Charles County, Maryland. 



CHELONIID^. 221 

The costal here described (plate 32, fig. 3) appears to have been the sixth of the right side, 
and to have belonged to an individual whose carapace had a length of about 400 mm. The 
length of the bone, from the neural border to the distal end, is 125 mm. The width at the 
middle of the length is 44 mm. The thickness at the sutural border is 5 mm. The rib adds 
about 3 mm. through the middle of the width. The distal end of the bone is cut off obliquely 
and the margin is smooth, showing that there were costo-peripheral fontanels and no suture 
with the peripheral. 

On the proximal end of the upper surface appears a portion of a vertebral scute, probably 
the fourth. The outer angle is distant 45 mm. from the neural border and the angle is less than 
90°. The sulcus between the third and the fourth costal scutes runs on the bone near the 
posterior border. 

The upper surface of the bone is markt by numerous vascular grooves. In general, these 
run toward the distal end, branching and anastamosing. When followed toward the proximal 
end they soon enter the bone. In the area of the vertebral scute the surface is pitted by vascular 
openings. The anterior border of the bone is grooved somewhat at right angles with the 
sutural edge. 

Family CHELYDRID^ Agassiz. 

Plastron loosely joined to the carapace; consisting of nine elements and considerably 
reduced. The entoplastron T-shaped; the bridge narrow. Nuchal bone with long costiform 
processes. A full series of neurals. Skull with temporal region incompletely rooft over; the 
postfrontal bones large. Quadrate notcht for passage of the stapedial rod. Crushing-surfaces 
without ridges and processes. Caudal vertebrae mostly opisthoccelous. 

At the present day this family is represented by 3 genera, Chelydra and Macrochelys of 
North America and Devisia of New Guinea. The first contains two species ; Macrochelys 
and Devisia only one each. Chelydra serpentina is the best-known species and ranges east 
of the Rocky Mountains from Canada to Ecuador. 

The members of this family are regarded as being among the most primitive of the living 
turtles. Nevertheless, known remains of the family have not been found in deposits earlier 
than the Upper Ohgocene. Chelydra murchisoni is found in the Upper Miocene ol Switzer- 
land and C. decheni in the Upper Oligocene of the Rhine region, near Bonn. 

While the Chelydridae are in many respects primitive in their structure, in other respects 
they have deviated considerably from their Amphichelydian ancestors. The roof of the tem- 
poral region has suffered considerable reduction. The plastron has undergone reduction. 
The writer can not believe that the opisthoccelous caudal vertebrae are primitive. The costi- 
form processes of the nuchal are a late acquisition. 

As the writer has stated elsewhere, he holds that the Chelydridae are related to the Chelo- 
niida through some Cretaceous ancestor of Toxochelys. Altho he has indicated (Bull. Amer. 
Mus. Nat. Hist., xxi, 1905, p. 167) that the Emydidae and the Testudinidae sprang from the 
Chelydridae he is now inclined to hold that they had their origin from the Dermatemydidae. 

Genus ACHERONTEMYS Hay. 

A genus of Chelydridae. Carapace broad, considerably deprest. Neural, bones eight, 
about as broad as long, mostly hexagonal, with the broader end forward. A single broad 
suprapygal. Peripherals, 1 1 pairs, placed opposite the ends of their respective costals. Verte- 
bral scutes very broad. 

Type: Acherontemys heckmani Hay. 

The relationships of the present genus are yet somewhat uncertain, but they are believed 
to be with the Chelydridje. A comparison of the plan of the carapace of the species described 
below with those of the carapaces of Chelydra and Macrochelys (Boulenger's Cat. Chelonians, 
pp. 22, 24) will show that there are great' resemblances. The nuchal bone has not the back- 
ward extension seen in the Emydidae. The peripherals do not alternate with the costals. 
Acherontemys differs from the living genera mentioned in having the costals more closely 
articulated with the peripherals and in possessing extremely broad vertebral scutes. 



222 



FOSSIL TURTLES OF NORTH AMERICA. 




Fig. 281. — Acherontemys heckmani. 
Carapace of type. X^. 



Acherontemys heckmani Hay. 

Fig. 281. 

Acherontemys heckmani. Hay, Proc. U. S. Nat. Mus. xxil, 1899, P- 23, plate vi ; Bibliog. and Cat. Foss. 
Vert. N. A., 1902, p. 446. 

The type ot the present species belongs to the U. S. 
National Museum. It was found near Roslyn, State of 
Washington, in what is known as the Roslyn sandstone, 
of the Miocene formation. 

The carapace (figure 281) is broad and must have 
been rather deprest. There are no evidences of serrations 
on the hinder border of the carapace. The length is 
181 mm.; the width, 118 mm. The median line appears 
to have a sort of keel, with low bosses. The sutures 
between the bones are distinct. There are 8 neurals. The 
first is nearly square; the eighth pentagonal and elon- 
gated; the others hexagonal. The nuchal is about twice 
as wide as long. The peripherals are nearly square, and 
those at the sides are placed opposite the ends of their 
respective costals. 

The sulci are distinctly imprest. The region of the 

nuchal scute is damaged. The vertebrals are extremely 

broad. The first has a width of 75 mm.; the second, 

90 mm.; the third, 85 mm.; the fourth, 75 mm.; the 

fifth, 65 mm. The costal scutes are correspondingly diminisht in transverse extent. The 

first, fourth, and fifth vertebrals are short. In the case of the fourth this is caused by the 

crossing of the sulcus between it and the third on the sixth, instead of on the fifth neural. 

Nothing is known regarding the plastron of this species. 

Genus MACROCHELYS Gray. 

Three or four additional, or supramarginal, scutes on each side. Orbits lateral. Tail 
with small scales inferiorly (Boulenger). 
Type: Macrochelys temmincki (Troost). 

This genus is represented in the living fauna by the alHgator snapper, a magnificent 
turtle that lives in the lower Mississippi River region. It reaches a large size and has a dis- 
proportionately large head. 

Macrochelys iloridana sp. nov. 
Figs. 181-285. 
Macrochelys floriJana, Hay, Bull. Amer. Mus. Nat. Hist, xxiii, 1907, p. 847, figs. I-4. 

Four peripheral bones of perhaps as many individuals, a portion of the Jarman collection 
in Vanderbilt University, indicate a hitherto undescribed species of alligator snapper. It was 
found in what are probably Peace Creek beds, Hillsboro County, Florida. 

A fourth left peripheral (fig. 282) is 46 mm. long, 34 mm. high, and 21 mm. thick. The 
upper and lower faces are of moderate convexity and meet in a subacute free border. At the 
hinder end of the bone is an excavation for a process of the hyoplastron, occupying nearly 
half the length of the bone. 

The right seventh peripheral (figs. 283, 284) is 60 mm. long, 50 mm. high, and 25 mm. 
thick. The upper border was articulated to the costal by a jagged suture. The slightly convex 
upper and lower faces meet to form an acute free border. As in M. temmincki, there is a 
long excavation for the hypoplastron. 

The ninth peripheral (fig. 285) has in the free border a notch and is tootht both in front 
and behind this notch. In M. temmincki there is a single tooth, the one in front of the notch. 

This species differs from the living M. temmincki in having the free border of the fourth 
peripheral far less acute, the upper face more convex, the rib-pit nearer the hinder end of the 



CHELYDRID^. 223 

bone, and no excavation for the hyoplastron; also in having the free border of the seventh 
peripheral much more obtuse and the upper border not in sutural contact with the costal; 
further, in having a single process on the free border of the ninth peripheral. 





284. 





Figs. 282-285. — Macrochelys foriduna. Peripherals of type. Xj. 

282. Fourth left peripheral, with section across middle of length. 

283. Seventh right peripheral seen from above, with section across middle of length. 

284. Seventh right peripheral seen from below. 

285. Ninth right peripheral seen from above, with section near hinder end. 

Genus CHELYDRA Schweigger. 

No supramarginal scutes. Orbit directed outward and upward. Tail with large scutes 
inferiorly (Boulenger). 

This genus is represented in North America, in a fossil state, only by the following species. 
Cope's Chelydra crassa will be described under the genus Hoplochelys. 

Chelydra serpentina Linnsus. 

Testudo serpentina, LlNN.«us, Syst. Nat., ed. X, 1858, p. 199. 

Chelydra serpentina, Schweigger, Prod., 1814, p. 23. — Boulenger, Cat. Chelonians, 1889, p. 20, 
figs. 3, 4. 

Cope (Extinct Batrachia, Reptilia and Aves of North America 1869, p. 125) reports 
briefly that Samuel R. Harrison, of Easton, Maryland, had found remains of this species in 
Pleistocene deposits at Oxford Neck, Talbot County, Maryland. They were accompanied 
by bones of Elephas amencanus, Cervus canadensis, Cariacus virgintanius, and Terrapene 
eurypygia. 

FamUy DERMATEMYDID.a; Gray. 

Plastron in most cases suturally articulated to the carapace; with an entoplastron, but 
without mesoplastra; the anterior and posterior lobes usually reduced in size. Nuchal bone 
with or without costiform processes. Neural bones reduced in number, except in Baptemys; 
some of the hinder costal bones meeting their fellows in the midline, except in the same genus. 
Peripheral bones in 10 or 11 pairs. Plastron furnisht with a full series of inframarginal 
scutes, except in Basilemys. The scutes of the anterior lobe perhaps in all cases modified 
from the condition seen in Baina. Caudal vertebrae in all the known forms procoelous. The 
hinder lobe of the plastron often with a scar for the pelvis, but the latter never suturally joined 
to the plastron. Temporal region not rooft over and no parieto-squamosal arch. Quadrate 
notcht behind for the stapedial rod. 



224 



FOSSIL TURTLES OF NORTH AMERICA. 



So far as the writer can determine, there is no good reason for separating the fossil genera 
that have been arranged under the name Adocidce from the Hving dermatemyds. The name 
Dermatemydie was employed by Gray in 1870, apparently a short time before Cope pro- 
posed the name Adocidce, and ought, under the form Dermatemydida:, to be used for the family. 
It is difficult to frame a definition of the family. Our knowledge of the few living forms 
is not complete. Of the great mass of the fossil genera we are acquainted with little more 
than the shells, and often with only small portions of these. Of no fossil genus have we the 
skull, except that of Baptemys. The limbs and feet and the caudal vertebrae are unknown. 
In the shells there is a great variety of structure. Perhaps no other family furnishes so many 
deviations from what is regarded as the normal condition in turtles. 

Usually in the members of this family some of the hinder neurals are aborted, a condition 
that permits one or more pairs of the hinder costals to meet their fellows in the midline. In 
Baptemys, however, there is a full series of neurals. In the living genera, Staurotypus and 
Claudius, the nuchal bone has long costiform processes, and the possession of these has been 
regarded as a characteristic of the family; but these processes are absent in Der.tiatemys ; 
while in Adocus and Xenochelys, and perhaps others, they are short; in Anosteira they are 
absent. The plastral lobes are in nearly all cases shortened and often narrowed. In the 

living Dermatemys (fig. 286) the lobes are quite 
well developt. In nearly all forms the plastron 
is suturally articulated with the carapace; but 
in living Claudius the union is ligamentous. 
In some of the fossil genera the sutures are 
coarse, forming a transition from the ligamen- 
tous connection to the closely knit sutures. 
In Adocus and Baptemys axillary and inguinal 
buttresses rise to the costals, or nearly so. In 
probably all genera, except Basilemys, there 
is a series of inframarginal scutes crossing the 
bridge. In Xenochelys and Staurotypus the 
number is reduced to two. In probably all 
genera there is some deviation in the arrange- 
ment of the scutes of the anterior lobe from the 
arrangement seen in such a primitive turtle as 
Ba'ena. In Adocus and some others, this pro- 
ceeds no further than the great development of 
the intergulars, by virtue of which the gulars 
are greatly reduced and pushed far from each 




Fig. 286. — Dermatemys mawi. Carapace and 
plastron. After Boulenger. 

infm I, etc., inframarginal scutes. 



Other. If this should in any cases have proceeded to the entire suppression of the gulars, 
the usurping intergulars would be mistaken for the abolisht scutes. Undoubtedly, in some 
cases, there has occurred either a coalescence or a suppression of scutes. In Baptemys 
ivyomingensis there are only 5 pairs on the plastron, excepting the inframarginals. Two pairs 
occupy the area covered in Adocus by the intergulars, gulars, humerals, and pectorals. 
The pectorals appear to have advanct so as partly to cover the epiplastrals. Three pairs of 
scutes ought to be found in front of this; but there is only one pair. In B. tricarinata, there 
are apparently distinct evidences of a sulcus crossing the front of the entoplastron and the 
middle of each epiplastron. This probably bounds the humerals in front. It seems probable 
that the area in front of this sulcus is occupied by the intergulars and that the gulars have 
been extirpated. 

The plastral scutes of Agomphus appear to be arranged like those of Baptemys. 

In Xenochehs we find the modifications of the plastral scutes to have gone still further. 
On each bridge there are only 2 scutes. What we must regard as the intergulars have coalesct 
into a single scute. This is followed by a scute on each side which does not come to the mid- 
line. The whole area extending from these to the femoral scutes is occupied by a single pair 
of scutes. The pair of scutes following the intergular may be gulars, but it appears more 
probable that the pectorals have advanct still further forward than in Baptemys and have 



DERMATEMYDID^. 



225 



Geological Distribution of the Genera of 
Dermatemydida. 



Formations. 


Genera. 


Recent 


Dermatemys, Staurotypus, Claudius. 




Pleistocene 
















Oligocene 


Xenochelys, Anosteira ? 




Anosteira, Baptemys, FPseudotrionyi, 
Kallistira, Notomorpha, Alamos- ■ 
cmys, Hoplochelys. 




Upper Cretaceous 


Adocus, Homorophus, Zygoramma, 
Agomphus, Compsemys, Basilemys. 



crowded the humerals against the intergulars into the place of the supprest gulars. Then 
the pectorals and the abdominals have coalesct. 

In Anosteira apparently the plastral scutes were so delicate that they left no impressions 
of the sulci on the bones. 

Usually there are no striking modifications of the scutes of the carapace; but attention 
may be called to those of Xenochelys, and more especially to those of Anosteira. 

As regards the geological continuance of the family, we find the earliest form, Basilemys, 
in the Judith River beds and three genera exist to-day. All together sixteen genera are here 
recognized, and these have the geological distribution presented in the accompanying table. 

Pseudotrionyx has been described from the 
Bruxellian of Belgium by Dr. Louis Dollo. 
There can be no doubt that it is related to Anos- 
teira of America. The Bruxellian beds are equiv- 
alents of our Wind River deposits. Anosteira 
anglica has been described from the Lower Oli- 
gocene of Hordwell, England. The character of 
the sculpture and the straightness of the hypo- 
xiphiplastral suture suggest a closer relationship 
with Pseudotrionyx than with Anosteira. Like 
Anosteira, Pseudotrionyx probably had only 10 
pairs of peripherals. 

We know nothing about the history of the 
Dermatemydidae prior to the Upper Cretaceous. 
Tretosternon Owen, of the Wealden, suggests 
strongly the genus Adocus; but the skull is said 
by Dollo {Peltochclys duchastclii. Bull. Mus. roy. 
d'hist. nat., Belgique, ill, 1884, p. 79) to have 
the temporal region protected by a bony roof. It is easy to conjecture that some form similar 
to Tretosternon was the Jurassic ancestor of the Dermatemydidae, which during the Upper 
Cretaceous times evolved into so many genera and species. 

As already stated, Pseudotrionyx of the Middle Eocene is evidently related to the Derma- 
temydidae. It is believed to be related also to Carettochelys insculpta, a species living in the 
Fly River, New Guinea. Happily, our knowledge of this species has been increast by the 
description of a better specimen than either of those previously known. This description is 
given by Mr. Edgar R. Waite in the Records of the Australian Museum, vi, 1905, pp. i lo-i 18, 
and is illustrated by four plates and three text-figures. Baur regarded this turtle as belonging 
among the Trionychidae, but as being closely akin to Pseudotrionyx and exhibiting connections 
with the Dermatemydidae. Waite shows that the turtle is a true Cryptodiran nearest to the 
Dermatemydidae, but also as connecting the Cryptodira with the Trionychidae. The animal 
is certainly a Cryptodire, but not a dermatemyd. It belongs to a family near the Derma- 
temydidae. Probably Pseudotrionyx belonged to the same family; and a comparison of the 
figures of the shell with those of Dollo's Peltochelys duchastellii (Bull. Mus. roy. Hist. Nat., 
Belgique, iii, 1884, p. 78, plate II) shows many striking resemblances. Waite states that 
the quadrate is not completely closed behind, but that there is a posterior notch, wide but not 
deeply cleft. On the other hand his figure (op. cit., plate xxvi, fig. 3) appears to show dis- 
tinctly that the stapes entered the tympanic cavity by a hole in the quadrate, just as it does 
in Trionyx. If this conclusion is correct, this differentiates the family from the Derma- 
temydidae; as does also the wide separation of the pterygoids by the palatines and the basi- 

sphenoid. ij 1 u 

It seems not unreasonable to suppose that from the Dermatemydidx there sprang the 
Emydidae and the Chelydridae. From the least differentiated Dermatemydidae, as Adocus, 
the Emydidae differ especially in the lack of intergulars and inframarginals; but both these 
series of scutes might cease to be developt. In one of the earliest of the Dermatemydidae 
there are no inframarginals, except at the axillary and inguinal notches. Were it not for the 
intergulars and the extraordinary sculpture of Basilemys we might regard it as an h-myd. 



»5 



226 FOSSIL TURTLES OF NORTH AMERICA. 

Key to the American Genera of Fossil Dermatemydid^. 

/i. Upper Cretaceous genera. 

a'. No inframarginals, coarsely sculptured with pits, furrows and pyramidal elevations Basilemys 

a^. Sculpture fine and granular Compsemys 

a'. Sculpture consisting of shallow pits. Borders of carapace acute-edged. Plastron 
rounded in front and behind, with full set of plastral scutes. Hinder marginal 

scutes rising well on the costal bones Adocus 

a*. Like Adocus, but with axillary and inguinal buttresses and costals sending long 

rib-heads into the peripherals. Bones thin Zygoramma 

a^. Shell thick and heavy; the free borders of carapace thick and obtuse. Hinder 

marginal scutes rising little or not at all on the costal bones Agomphus 

a°. Vertebral scutes said to be usually narrower than the neural bones Homorophus 

A A. Tertiary genera. 

a', hike Adocus, but hinder marginal scutes not rising on costal bones. Tor.'^jon.. . Alamosemys 

a^. See A. a^ above. Hinder lobe of plastron pointed. Midway Agomphus 

a'. Shell thick; free borders acute; three ridges along back; the plastron rather loosely 

joined to carapace. No inguinal buttresses. Torrejon Hoplochelys 

a*. Like Hoplochelys, but without inguinal buttresses. Wasatch Kallistira 

a'. Not well known. At least the anterior peripherals obtuse. Wasatch Notomorpha 

a°. A full set of neurals. Carapace smooth, with a median carina on rear of cara- 
pace. Plastron sutured to carapace. Wasatch, Wind River, and Bridger. . . . Baptemys 
a'. Shell finely sculptured. Plastron much reduced and loosely joined to the carapace. 

Bridger Anosteira 

a*. Shell smooth; no buttresses; five pairs plastral scutes. Oligocene Xenochelys 

Genus BASILEMYS Hay. 

Shell highly sculptured. Epiplastra much thickened. Bridge wide. Intergular scutes 
present. Pectorals greatly expanded at the midline, narrowed laterally. An axillary and an 
inguinal scute but no other inframarginals. 

Type: Compsemys variolosus Cope. 

This genus differs from other known genera of Dermatemydidae in having no infra- 
marginals, except the axillary and the inguinal. 

Basilemys variolosa (Cope). 
Plate T,i, fig. 4; plate 34, fig. i; text-fig. 287. 

?Compsemys ogmius. Cope, Vert. Cret. Form. West, 1875, pp. 91, 261; Proc. Acad. Nat. Sci. Phila. 

1875, p. 9; Brit. N. A. Bound. Surv., Report on Geol. and Resources 1875, p. 336. 
Compsemys variolosus. Cope, Proc. Acad. Nat. Sci. Phila. 1876, p. 257; Bull. U. S. Geol. Surv. Terrs., 

m, 1877, p. 573. 
Adocus variolosus, Lambe, Ottawa Naturalist, XV, 1901, p. 63, plates iii-vi; Cont. Canad. Palaeont., 

II (4to), p. 39, plate ii, text-figs. 4-6. 
Basilemys variolosus, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445. 
Adocus (Basilemys) variolosus, OsBORN, Cont. Canad. Palxont., Ill (4to), 1902, pp. 12, 16. 
Basilemys ogmius. Hatcher, Bull. U. S. Geol. Surv. No. 257, 1905, p. 76. 

The type of the present species consists of nearly the whole of the plastron, various periph- 
eral bones, and two imperfect costal plates. These are now in the American Museum of 
Natural History, and bear the catalog number 1465. This type, with fragments of other 
individuals, was collected for Professor Cope, in 1876, by Mr. Charles H. Sternberg, in the 
Judith River beds of Montana. Since that time other specimens of the species have been 
collected by members of the Geological Survey of Canada, in Judith River deposits, just 
north of the United States boundary line and east of the Rocky Mountain range. More 
accurately, the remains were taken on Mackay Creek, along Old Man River, and on Red 
Deer River. 

Fig. 287 is reproduced mostly from Cope's type, but it is probable that the fragment of 
bone around the axillary notch and the piece of epiplastron do not belong to the same indi- 
vidual as the remainder of the specimen, these anterior pieces being somewhat larger than we 



DERMATEMYDIDj^. 



227 



might expect. The diagrammatic figure has been constructed partly from the type and 
partly from materials belonging to the Canadian Survey. 

This species was a large one, and it is distinguisht by a rather remarkable form of orna- 
mentation. The length of the plastron of the type was not far from 670 mm. and the total 
length of the carapace approximated 775 mm. The form and the elevation probably resembled 
closely those of the species oi Adocus. The sculpture seems to be an exaggerated development 
of that of the genus just mentioned. It resembles considerably that of some species of the 
Trionychidae, but the pits are more commonly arranged in rows, and the intervening ridges 
are more acute. Often where three ridges meet, there is formed a sharp trihedral elevation. 
The effect is to produce a very rough surface. There are usually about three rows of pits 

in 10 mm. The whole shell is covered with this sculp- 
ture. It is best developt on the upper and lower surfaces 
of the anterior and posterior peripherals. On the upper 
halves of the peripherals of the bridge it may be obscure. 
So also sometimes on parts of the plastron, as in the case 
of the specimen in the collection of the Canadian Survey. 
The bridge of the plastron is very wide antero-pos- 
teriorly, the anterior and posterior lobes relatively short. 
The rims of the lobes are much thickened, the interior 
portions considerably thinner. The epiplastron of the 
Canadian specimen (plate 32, fig. 4), which was about 
as large as Cope's more complete specimen, is 38 mm. 
thick near its union with its fellow. This thickness 
diminishes toward the axillary notch, where it is 28 mm. 
Behind the entoplastron it is only 15 mm. or even less. 
The epiplastron of Cope's material has an extreme thick- 
ness of 5 1 mm. The hyoplastral and hypoplastral bones 
are only 10 mm. thick where they join. At the inguinal 
notch the rim of the hinder lobe is 40 mm. thick. This 
gradually diminishes to 12 mm. near the midline behind. 
The anterior lobe is about 325 mm. wide and 144 
mm. long, measured from a line joining the two axillary 
notches. Its sides slope forward to a rather blunt point. 
The lateral face of the thickened rim stands at a right 
angle with the flat lower surface of this lobe. The sculp- 
ture rises on this face and extends for a distance on the 
upper surface. 

The entoplastron is large, being about 160 mm. wide, 
but only 100 mm. long. It is hexagonal, with the lateral 
borders shortest. 

On the lower surface of the front lobe is found a 
half of plastron. Xj. Mostly from p^j^ ^f j^^g^ intergulars which extend backward to the 
No. 14.65 A. M. N. H. anterior border of the entoplastron and separate widely 

the reduced gulars. The humero-pectoral sulcus is at first directed backward from the 
axillary notch for about 50 mm., then is turned WddenlyS'forward and inward to the middle 
of the entoplastron. 

The posterior lobe is approximately 340 mm. wide and only 160 mm. long. It is broadly 
rounded behind. On the upper surface of this lobe is a large, smooth scar which marks the 
point of attachment of the pubis. 

The pectoral scutes are narrow at their outer ends. The abdominal scutes are large. 
The median sulcus pursues a very irregular course from the front to the rear of the plastron. 
The bridge is remarkably wide, being about 360 mm., considerably more than one-half 
of the length of the plastron. 

Behind the axillary notch there is a rather short and wide axillary scute, followed by the 
narrowed lower end of the fourth marginal. The fifth marginal is likewise narrow, but the 
sixth is greatly expanded. The seventh and eighth are pointed at their lower ends. There is a 




Fig. 287 



Right 



228 FOSSIL TURTLES OF NORTH AMERICA. 

single narrow inguinal. We see, therefore, that, excepting the axillary and the inguinal scutes, 
there were no inframarginals. This conclusion is confirmed by the more complete shell of 
Rasilemys sinuosa Riggs. 

Of the elements of the carapace the nuchal is unknown and but little is known of the neu- 
rals. With the type are parts of 2 costals. One of these appears to be the eighth of the right 
side. The length of the fragment is 144 mm.; its width was at least 56 mm. At the middle 
of the width the thickness is 13 mm. The borders and the course of the rib on the inferior 
surface show that the costal was curved backward from its proximal to its distal end. Not far 
from its hinder border it is traverst by a deep dermal sulcus. The position of the other costal 
fragment can not be determined. 

Of the peripherals there are present an anterior one, probably the second, the lower halves 
of most of those forming the bridge on the right side, and those of the right side from the 
inguinal notch to the pygal. In the collection of the Canadian Survey the third right peripheral 
is represented by the portion bounding the axillary notch. The greater part of the pygal is 
with Cope's type. Therefore, with the exception of the nuchal, one anterior peripheral, and 
the outer halves of the bridge peripherals, we are acquainted with the whole rim of the carapace. 

The anterior peripherals did not project so far beyond the soft parts of the animal as did 
the posterior. The supposed second projected beyond the soft skin of the under side 52 mm. 
Its length along the free border is 90 mm. The thickness is 21 mm. The portion which articu- 
lated with the first costal is missing. The upper surface of the bone is nearly flat; the lower 
is somewhat convex; the free border is acute. 

The third peripheral, as represented by the Canadian specimen, has the thinner portion 
which articulated with the first costal broken away. The sutural edge which joined the outer 
anterior angle of the hyoplastron is present. On the anterior end of the outer surface is a 
right-angled ridge, which farther forward passes into the sharp free border of the carapace. 
Below this ridge the sculptured surface lookt downward toward the axillary notch; the surface 
above the ridge was a part of the upper surface of the shell. The whole length of the bone is 
about 90 mm. and its greatest thickness is 38 mm. 

The figure shows what parts of the various bridge peripherals are present. Probably just 
beyond the line of fracture the peripherals curved upward to join the lower ends of the costals. 
This outer, or upper, portion of these bridge peripherals appears to be represented by one bone 
in the Cope collection. The costal margin of this bone was about 18 mm. thick and this 
border is nearly straight. The length of this peripheral is 103 mm. and it rises at least 1 10 mm. 
The sculpture of the outer surface is not so coarse as on most of the bones. 

The seventh peripheral (plate 34, fig. i), the one entering into the inguinal notch, is thick 
and heavy. Its length is 82 mm.; its thickness anteriorly, 44 mm., posteriorly, 20 mm.; its 
height, at least 70 mm. Its free border is rounded in the middle of the length, becoming 
broader and flatter anteriorly, sharper posteriorly. The figure just referred to shows the 
details of the sculpture. The next four peripherals have respectively the lengths 100 mm., 87 
mm., 62 mm., and 53 mm. The heights vary from at least 100 mm. in the eighth to 75 mm. in 
the eleventh. The upper border of all appears to be broken away, but the suture evidently was 
near. The eighth, ninth, and tenth have their outer surfaces somewhat concave from above 
downward, so that these have a slight upward flare. A fragment of the pygal has on it the 
descending sulcus, thus showing that the bone was about 60 mm. wide. Its free border is 
acute and the bone is 18 mm. thick, 70 mm. above the free border. 

The connection of the costals with some of these posterior peripherals is interesting. It is 
well shown in an eighth right peripheral in the Canadian collection. This is broken so as to 
show that the end of the rib beyond the costal plate extends downward into the substance of 
the peripheral about 30 mm., forming a gomphosial articulation. No such articulation is seen 
in the bridge peripheral above described. 

The greater portion of the pygal is present in the type of the species. It had a length of 
60 mm. along the free border and a height of about 75 mm. The outer surface is nearly flat, 
the inner convex. The free border is acute, as is that of most of the peripherals. 

So far as can be determined, the sulci between the costal and the marginal scutes followed 
pretty closely the sutures between the costal and the peripheral plates. No sulci are found 
crossing the two costal plates present. On the eighth and ninth peripherals a deeply imprest 



DERMATEMYDID^. 



229 



sulcus runs an irregular course across the upper ends, 65 mm. above the free border, then rises 
and does not appear on the more posterior peripherals and pygal. 

Mr. L. M. Lambe, of the Canadian Geological Survey, describes (op. cit., p. 40) some 
conical, rugose bones which he believes belonged on the tail of this species. 

Cope speaks of the dermal sulci as being deeply imprest. This is true of many of them, 
especially of those of such costals as are known — the anterior plastral sulci, and some others; 
but many are extremely narrow and shallow, and are difficult to follow as they wander over 
and among the pits and ridges of the sculpture. 

Compsemys ogmius was based on a fragment of what Cope regarded as a costal plate and 
on a fragment of the plastron. These were never figured. They were obtained in the Judith 
River beds by Dr. G. M. Dawson, of the British Boundary Survey, at a point along the Milk 
River, near the boundary between Assiniboia and Alberta. These fragments are now at 
Ottawa. An examination of the bone identified as part of a costal shows that it is really a part 
of a bridge peripheral, and that it possibly belongs to Basilemys variolosa. The fragment is 
exceedingly poor. It is only 55 mm. square and shows only a small area of the sculpture, the 
remainder having been weathered off. Where shown, the ornamentation is obscure. The 
piece of plastron is 93 mm. long, 35 mm. wide, and 12 mm. thick. The sculpture is nearly 
effaced by weathering. While these bones may belong to B. variolosa, there is too much 
doubt regarding them to permit us to adopt for them and the last-named species the earlier 
name ogmius. Even if ogmius were a species distinct from variolosus, it is doubtful whether 
new materials could be identified by means of the type. 

Cope's assignment of the species described above to the genus Compsemys is an error. 
The sculpture of the latter is of a very diflFerent character and there were probably infra- 
marginals. 



288. 





Figs. 288 and 289. — Basilemys sinuosa. Carapace and plastron. Xi'i. 
288. Carapace. 289. Plastron. 



Basilemys sinuosa Riggs. 

Plate 33, figs. I, 2; teit-figs. 288, 289. 

Basilemys sinuosus, Riggs, Pubs. Field Columb. Mus., Geol. ser., 11, 1906, p. 249, plates Ixxvi, ixxvii. 

The fine specimen on which this species is founded was collected by Dr. E. S. Riggs, of 
Field Natural History Museum, Chicago. It was secured in the Laramie deposits of Chalk 
Buttes, near Powderville, Custer County, Montana. With it were found bones of Trueratops, 
Trachodon, and other characteristic Laramie fossils. The shell is nearly complete. Of the 
plastron nothing is missing, except some parts of the bridge peripherals. Of the carapace 



230 



FOSSIL TURTLES OF NORTH AMERICA. 



Vertebral. 


Length. 


Width. 




loo 


160 




•45 


100 




165 


100 




I2S 


90 




140 


*3S 



some portions of the neurals and the contiguous borders of the right third and fourth costal 
plates are wanting. 

The carapace (plate 33; text-fig. 288) is deprest, due probably in some degree to pressure. 
The anterior border is excavated over the neck, broadly rounded behind. Behind the ingui- 
nal notches the borders are somewhat flared upward. 

The length of the carapace from the bottom of the notch in front to the rear, measured in 
a straight line, is 715 mm.; the breadth is very close to 585 mm. The anterior notch is 22 mm. 
deep. The free border in this notch is about 25 mm. thick. On each side of the midline the 
border thins rapidly and soon forms an acute edge, which continues to the axillary notch. 
Behind the inguinal notches the free edges are acute. 

The nuchal bone measures 85 mm. along the midline; its width is 145 mm. The first 
neural was about 80 mm. long and 60 mm. wide behind. The second neural is oval, 68 mm. 
long, 40 mm. .wide. The third is broadest in front, 80 mm. long, 50 mm. wide. The fourth 
neural is wanting; the fifth is defective. The sixth is 70 mm. long, 50 mm. wide. The seventh 
and eighth are small and irregular in form. There is a small first suprapygal. The second 
is bifurcate, as in Testudo. It measures along the midline 60 mm.; its lateral extent is 170 

mm. The third suprapygal is 72 mm. along the midline and 135 
mm. wide. The pygal bone is 52 mm. high and 75 mm. wide. 
The tenth peripheral bone is 85 mm. along the free border and 
102 mm. high. There are 11 pairs of peripherals. 

The nuchal scute is small, about 25 mm. long and 15 mm. 
wide. The first vertebral scute is unsymmetrical. On the left 
side the anterior border extends 100 mm. from the midline; on the 
right side apparently only 60 mm. The left appears to be the nor- 
mal side. The table herewith gives dimensions of the vertebrals. 

It will be observed that, with the exception of the first and the last, the vertebrals are 
considerably longer than wide. The costal scutes are large. The second has a longitudinal 
extent of 160 mm. and a height of 240 mm. They extend far below the costo-peripheral 
sutures. Of the marginal scutes there are 12 pairs. The second extends from the free border 
42 mm. to the first vertebral scute. The third has a height of 60 mm.; the ninth a height of 
60 mm.; the twelfth, a height of 75 mm. 

On the lower side of the first and second peripherals the portion covered by the horny 
scutes is about 50 mm. wide. Toward the nuchal bone and the axillary notch this narrows 
greatly. Behind the inguinal notches the horn-covered surface on the lower side of the periph- 
erals is about 45 mm. wide to the midline behind. 

The plastron (plate 33; text-fig. 289) has a total length of 660 mm. The lobes are short, 
the bridges wide. The length of the anterior lobe, to a line joining the bottoms of the axillary 
notches, is 160 mm. The breadth, taken from the inner border of one axillary notch to the 
other, is 330 mm. 

Anteriorly the lobe ends in a beak as prominent as that of many species of Testudo. 
From the anterior end of one gulo-humeral sulcus to the other, the width is 95 mm. The beak 
extends 42 mm. in front of this. On the lower surface the beak is nearly flat, but toward the 
front it develops a broad median channel. Laterally the borders of the beak, like those of 
the whole anterior lobe, are subacute. From this subacute edge the bone rises abruptly and 
nearly perpendicularly, finally rounding off into the convex upper surface of the beak. The 
maximum thickness of the bone is 50 mm. On the upper side of the beak the ornamented 
surface extends back about 55 mm. From the sides of the beak this sculptured surface narrows 
toward the axillary notch. At the junction of the epiplastron with the hyoplastron the bone 
is 35 mm. thick. The median portions of the anterior lobe are much thinner. 

The entoplastron is short but very wide. Its fore-and-aft extent is 1 10 mm., the breadth, 
145 mm. The form is shown in the figures. 

The bridges are about 370 mm. wide. The hinder lobe has a length of 145 mm. and a 
width of 300 mm. At the borders, for some distance behind the inguinal notches, the bone 
turns abruptly and perpendicularly upward to the summit of a ridge running backward from 
the inguinal notch. From the summit of this ridge the bone slopes rapidly downward to the 
central portion of the lobe. At the hypoxiphiplastral suture the ridge is 50 mm. above the 



DERMATEMYDID^. 23 1 

lower surface of the plastron; at the femoro-anal sulcus, only 20 mm. On the upper surface 
of each xiphiplastron is a scar for the pubis. This scar is 55 mm. long and 30 mm. wide. 
The inner borders of the two are 100 mm. apart. The hinder end of the lobe is truncated 
and bent upward as the hinder extremity is approacht. 

The median portion of the plastron is very concave, a condition which appears to indicate 
that the individual was a male. 

On some parts of the plastron the sulci bounding the epidermal scutes are very distinct; 
in others they are obscure, but determinable. They consist of very narrow, thread-like grooves, 
some of which pursue their course at the bottoms of broad channels, while others keep on 
the level of the general surface. The median sulcus runs an extremely irregular course, being 
first on one side of the midline, then on the other. The intergulars occupy the whole lower 
surface of the lip, extending backward 100 mm. along the midline. The gulars meet at the 
midline a distance of 35 mm. Their posterior borders run parallel with the anterior. 

At the midline the humerals join for a distance of only 8 mm.; but from this they expand 
rapidly and their outer ends reach about 60 mm. behind the axillary notch. The pectoral 
scutes are, fore and aft, extremely broad, meeting along the midline a distance of 195 mm. 
Their outer ends are only 30 mm. wide. The abdominal scutes extend along the midline 160 
mm., while their outer borders are 240 mm. long. The length of the femorals at the midline 
may be taken as 90 mm.; that of the anals as the same. 

The scutes covering the bridge are separated from the plastral scutes just described by a 
nearly straight sulcus running from the axillary to the inguinal notch. Of these scutes the 
most anterior and the posterior alone appear to represent the inframarginal series. The 
others are bridge marginals. Of these, one, the sixth marginal, has become greatly expanded 
at the abdominal end; the other marginals are greatly narrowed at their lower ends. This 
absence of a series of inframarginals is remarkable in this family. 

The sculpture of this species resembles closely that of its predecessor, B. variolosa. The 
carapace and the plastron are both rough with sharp elevations, which are usually triangular 
pyramids. These are mostly arranged in rows, of which three or four are spanned by a line 
10 mm. long. 

The present species differs from B. variolosa in various points. The gulars of the Judith 
River species are crowded far from the median line; in B. sinuosa they are in contact with 
each other. The pectoral scutes of B. sinuosa extend backward nearer to the hyohypoplastral 
suture than they do in B. variolosa. The hinder extremity of the plastron of B. sinuosa is trun- 
cated, bent upward somewhat, and has its borders acute; that of B. variolosa is broadly 
rounded, flat, and the borders are thick and obtuse. From some peripherals present, belonging 
to the type of B. variolosa, it appears that the sculptured, horn-covered surfaces on the under 
side of the peripherals are considerably broader than they are in B. sinuosa. On the eighth 
peripheral this surface is 70 mm. wide; in B. sinuosa it is only 50 mm. wide. The plastron 
of the type of B. variolosa is only about 10 mm. longer than that of B. sinuosa Riggs. 

A fragment of the epiplastral Hp of what is regarded as this species was found by Mr. 
Barnum Brown of the American Museum, on Hell Creek, Dawson County, Montana. 

Basilemys imbricaria (Cope). 
Plate 32, figs. 5, 6, 7; teit-figs. 290, 291. 

Compsemys imhricarius, CoPE, Proc. Acad. Nat. Sci. Phila. 1876, p. 257; Bull. U. S. Geol. Surv., iii, 

'877, p. 573. 
Basilemys imhricarius. Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445.— Hatcher, Bull. U. S. 

Geol. Surv. No. 257, 1905, p. 77. 
Adocus {Basilemys) imhricarius, OsBORN, Cont. Canad. Palaeont., Ill (4^0), 1902, p. 16. 

This species was founded by Professor Cope on very unsatisfactory materials. The type, 
to which only three fragments (No. 6102 of the American Museum of Natural History) can be 
referred with any certainty, was found in the Cope collection mingled with fragments of two 
or three other species. The identified bones are here figured of the natural size (plate 32, 
figs- 5, 6, 7). All are probably portions of costal plates. The larger piece is traverst by a 
narrow and sharply imprest sulcus, and appears to be the fragment mentioned by Cope as 



232 



FOSSIL TURTLES OF NORTH AMERICA. 



having the direction of the ridges of sculpture running at right angles with the sulcus. The 
inner surface of the bone is removed, so that the thickness of the fragment can not be deter- 
mined. It was more than 6 mm. 

The piece of medium size has a sutural edge along one side. The thickness is 6 mm. 
where thickest, 5 mm. where thinnest; and it may be the fragment whose measurement Cope 
gave. The smallest piece of bone is only 3 mm. thick. 

This species is distinguisht especially by its sculpture. It is thus described by Cope: 

It consists, in the Compsemys imbricarius, of excavations bounded on the sides by a short ridge 
each, which [excavations] alternate with each other. Thus each bounding ridge terminates abruptly 
at the fundus of one of the fossae, while the other end of the fossa rises and contracts into another 
ridge. The result is precisely that seen in the interior sculpture of Saracenic domes and niches, 
and is one quite unique among tortoises. The direction of the ridges is at right angles to the costal 
dermal sutures. 

Cope states that three of the fossae measure in length 6.5 mm. and crosswise, 5 mm. In the 
case of the largest of the three fragments of the type three fossae taken together measure 7 mm. 
and crosswise, 6 mm. 

While this style of ornamentation appears to be very peculiar, something scarcely dis- 
tinguishable in pattern may be seen here and there on the carapace of B. variolosa, and for 
that reason the present species has been referred to Basilemys. In fact Cope has labeled as 
Compsemys tmbricaria some fragments the sculpture of which appears quite identical with that 
of B. variolosa. With these latter fragments, however, there is what seems to be the thickened 
rim of the front of the carapace (fig. 290, No. 6100 A. M. N. H.), and this is plainly different 
from that of B. variolosa. Evidently there is another species occurring with B. variolosa, 
related to it, but differing in important characters. For this species we may for the present 
retain the name Basilemys imhricaria. 

The remains of this form were collected in 1876, in the Judith River beds of Montana, by 
Mr. Charles H. Sternberg. 

Fig. 290 represents a section across the supposed anterior peripheral, No. 6100 A. M. N. H. 

The part of this peripheral which joins the costal 
,^^ is missing. On the under side it appears to extend 

■''llJmlll 11 lfl)V backward to the line reacht by the soft skin, a 

jflllM lllll Ijk distance of 27 mm. from the free border. The 

,.g extreme thickness of the fragment is 16 mm. The 

upper surface is slightly convex; the lower surface 

Figs. 290 AND 291. -5<2.</.my^/mJnW;fl. strongly SO. The ornamentation is coarse, there 

Sections. X§. No. 6101 A. M. N. H. being 3 fossae in 9 mm. This peripheral differs from 

290. Section across peripheral. one in the Same region of B. variolosa in having 

201. Section across border of xiphiplastron. , , , r i i-irii 

' the sculptured surface on the under side of the bone 

much narrower from the free edge to the skin line in proportion to the thickness of the bone. 

It is to be noted that these coarsely sculptured fragments possibly do not belong to B. 
imhricaria. 

In the Cope collection there is another fragment (No. 610 1) which possesses a sculpture 
like that of the specimens just described, and this is evidently a portion of the left xiphiplastron 
(fig. 291). There are 3 fossae in 8 mm. It differs from that of 5. variolosa in having a sharp 
border separating the lower surface from the surface which looks outward and upward. In 
B. variolosa the lower surface of the hinder lobe rounds gradually into the upper surface. 

Professor Cope has labeled as Compsemys imhricaria other specimens from the Judith 
River beds which have a sculpture similar in pattern but much more delicate. In these 
(No. 6103 A. M. N. H.), some of them fragments of costals, there are 4 fossae in a line 5 mm. 
long. The scutal sulci are thread-like. Other fragments, peripherals from the bridge perhaps, 
have similar ornamentation but the sulci are very broad. It seems very probable that the 
fragments here described belong to more than one species, but the discovery of additional and 
much better materials will be required in order to determine the structure and generic position 
of Cope's Compsemys imhricaria. 




DERMATEMYDID^. 233 

Genus COMPSEMYS Leidy. 

Little-known turtles belonging probably to the Dermatemydidae. Free surfaces of the 
bones of carapace and plastron ornamented with small, close-set, enameled tubercles which 
produce the appearance of shagreen. Neurals hexagonal, with the broader end forward. 
Costals without distal prolongations into the peripherals. Sulci thread-like. The plastron 
suturally articulated with the contiguous peripherals and sending up axillary and inguinal 
buttresses to the costals. No evidences of mesoplastra. Inframarginal scutes probably on 
the bridges. Vertebral scutes not greatly expanded. 

Type: Compsemys victus Leidy. 

The genus Compsemys was establisht in 1856 by Professor Leidy, to receive the scanty 
remains which he named Compsemys victus. Later discoveries have added little to our 
knowledge regarding the genus; altho it is evident that it is represented over a wide area of 
territory and thru a considerable range of deposits, having been reported from levels rang- 
ing from the Judith River beds to the Denver. The only characterization that Leidy gave to 
his genus is exprest in the following words: 

The peculiarity of the specimens which has led to the proposal of the genus consists in their exterior 
surface being closely studded with uniform granular tubercles, which give to them a shagreened appear- 
ance, quite different from anything I have had the opportunity of seeing in other turtles. 

At a later time Professor Cope assigned to Compsemys Leidy's Emys obscurus and after- 
wards returned it to Emys. At the same time he referred to Compsemys his own Adocus 
lineolatus without explanation. These two species undoubtedly belong elsewhere. The 
same verdict must be pronounct regarding the three species described by Cope in 1875 and 
1876, from the Judith River beds, and called by him Compsemys ogmius, C. tmhricurtus, 
and C. variolosus. In 1877 Cope described his Compsemys plicatula from the Jurassic of 
Colorado, and there can be little doubt that his generic reference of the specimen was based on 
the similarity of the sculpture to Leidy's species. Especially since Dr. Baur's description of 
Cope's C. plicatula it has been regarded as representing the characters of Compsemys. How- 
ever, there can be no doubt that plicatula belongs to a wholly different genus from victa, and 
to another superfamily. Most of the references in scientific literature to the genus Compsemys 
(for which see the writer's Bibliography and Catalogue of Fossil Vertebrata N. A., 1902, 
p. 437) are to the genus as typified by C. plicatula and are therefore to be transferred to 
Glyptops. When Baur (Proc. Acad. Nat. Sci. Phila. 1891, p. 412) states that the Laramie 
forms of Compsemys show all the characters of the Jurassic form he seems to have had in mind 
Cope's Compsemys variolosa, but this certainly has no mesoplastron. 

So far as at present known the only species to be assigned with any certainty to this genus 
is the type, C. victa. It is probable that when the form that has been reported to occur in 
the Judith River beds is better known it will prove to be a second species. 

Compsemys victa Leidy. 

Plate 34, figs. J, 3; teit-figs. 292-295. 

Compsemys victus, Leidy, Proc. Acad. Nat. Sci. Phila. 1856, p. 312; Trans. Amer. Philos. Soc, xi, 
i860, p. 152, plate vi, figs. 5-7. — CoPE, Trans. Amer. Philos. Soc, xiv, 1869, p. 124; Seventh Ann. 
Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 454; Bull. U. S. Geol. Surv., i. No. 2, 1874, p. 30; 
Vert. Cret. Form. West, 1875, pp. 91, 261, plate vi, figs. 15, 16; .'Brit. N. A. Bound. Comm. Report, 
1875, pp. 333, 336; ?BulI. U. S. Geol. Surv., iii, 1877, p. 573. — ?Cross, Monogr. U. S. Geol. Surv., 
XXVII, 1896, p. 227.— .'Marsh, Monogr. U. S. Geol. Surv., xxvii, 1897, p. 527.— Hay, Bibliog. and 
Cat. Foss. Vert. N. A., 1902, p. 437. 

Professor Leidy's type of the present species consisted of a neural; a considerable portion 
of a costal, regarded as a fifth; and a fragment of the eighth costal. These are now in the 
U. S. National Museum and bear the number 960. They were secured in deposits of probably 
Laramie age, at Long Lake, North Dakota. The species was afterward reported by Cope 
from supposed Laramie deposits in Colorado, now regarded as Arapahoe or Denver (Cross, 
op. cit., pp. 227, 244), and with doubt from Judith River beds (Cope's Fort Union) and from 



234 



FOSSIL TURTLES OF NORTH AMERICA. 



beds of the same period in the region about Milk River, British America. As the Judith 
River beds are now known to be much lower in the geological scale than the Laramie it is 
probable that a distinct species is there included. The Arapahoe and Denver beds being prob- 
ably above the Laramie, it is not improbable that the remains reported from that horizon by 
Cope and Marsh belong to a third species of the genus. 

Leidy's type indicated a turtle whose carapace had a length of about 365 mm. The neural, 
regarded as the fourth, was 26 mm. long and 27 mm. wide. The costal plate believed to be 
the fifth, was 28 mm. wide at the middle of the length. It is rather strongly archt, showing that 
the shell was not deprest. This costal had a thickness of 7 mm. where it joined the neurals. 
It is crost at the proximal end by the costo-vertebral sulcus, from which proceeds the sulcus 
that separated the third and fourth vertebral scutes. The position of the longitudinal sulcus 
indicates that the vertebrals had a width of about 65 mm. Leidy's estimate that they were 
2 inches wide is too small. 

The specimens figured by Cope in his Vertebrata of the Cretaceous Formations of the West, 
plate vi,figs. 15, 16, were collected in 1873, in northeastern Colorado. No statement is made as 
to the exact locality, but they probably came from the Denver beds in the region about Bijou 
Creek. We can not be really certain that they belong to Leidy's species. Cope's fig. 16 
represents a posterior peripheral, apparently the ninth of the left side, with the sulcus between 
the third and fourth costals running down its anterior half. The bone is 39 mm. high, 32 mm. 
wide at the free border, and 9 mm. thick at the costal border. There is no pit for the rib-end. 
The bone thins to an acute free border. The upper surface is only slightly concave. The 
sculpture resembles that of the 
type of the species. A remarkable 
feature of this bone is the low 
position of the costo-marginal 
sulcus. This runs much nearer 
the free than to the costal border. 

Figs. 292-295. — Compsemys victa. 
Fragments of shell, xj. 

292. Portion of right costal. No. 6096 

A. M. N. H. 

293. First right peripheral. No. 1085 

A. M. N. H. 

294. Fragment of bridge peripheral. No. 

998 A. M. N. H. 

295. Portion of right hyoplastron. No, 

1015 A. M. N. H. 

In Glyptops plicatulus, as is usual in turtles, it runs nearer the costal border. In the periph- 
eral here described the scute-covered surface on the inferior side of the bone extends to within 
15 mm. of the costal border. The granulation is finer than on the upper side of the bone. 
The other fragment figured by Cope furnishes little additional information. 

A right eighth costal, No. 6096 of the American Museum of Natural History, collected by 
Mr. J. C. Isaac, in 1877, in the Laramie beds, on Lance Creek, Wyoming, was at least 40 mm. 
wide and from 5 mm. to 8 mm. thick (plate 34, fig. 3; text-fig. 292). The proximal portion and 
a part of the hinder border are broken away. On the lower surface there is the base of a 
strongly developt rib-head; but there is no ridge corresponding to the rib, nor any projecting 
distal end of the rib, such as we find in Glyptops. Near the hinder border of the bone is a sulcus, 
that separating the fourth costal scute from the fifth vertebral. On the peripheral border are 
two loops of a sulcus, one narrow, the other wider. These appear to have proceeded from the 
peripheral; but as the peripheral figured by Cope shows the costo-marginal sulci to have run 
low down on the peripherals, the presence of these loops on the costal is at present inexplicable. 
Similar irregularly meandering sulci are seen on other bones. The oblique hinder sutural edge 
of the costal probably articulated with the eleventh peripheral and with the suprapygal. The 
fourth costal scute may have occupied a portion of the suprapygal, as it does in Kinosternon. 
In the U. S. National Museum there is a neural, the second or fourth, which was collected by 
Mr. J. B. Hatcher, on Lance Creek, Wyoming. 




dermatemydidje. 235 

In 1902, Mr. Barnum Brown, of the American Museum, collected a few fragments of this 
species in Laramie beds on Hell Creek, Dawson County, Wyoming. One is the first right 
peripheral (fig. 293). The individual (No. 1085 A. M. N. H.) was a relatively small one. The 
fore-and-aft extent of the bone is 23 mm., and the thickness of the hinder border, 5 mm. The 
free edge is acute. The first marginal scute is only 5 mm. antero-posteriorly where it joins the 
second. The latter widens to 9 mm. at the suture between the first and the second peripherals. 
On the under side of the bone the sculptured, horn-covered surface is about 7 mm. wide at 
the suture with the second peripheral, but toward the nuchal it narrows to 3.5 mm. 

Of the bridge peripherals there is a portion of one in the American Museum, No. 998, 
collected by Mr. Brown in 1900, in Laramie deposits of Wyoming, about 40 miles west of 
Edgemont, South Dakota. This fragment (fig. 294) shows that there was no sharp carina 
above the bridge, but an obtuse, rounded ridge. Fig. 2, plate 34, represents what is probably 
the distal end of the fourth costal. Besides the descending sulcus there are again seen some 
irregular loops coming up from the contiguous peripherals. 

Of the plastron there are only fragments known. Fig. 295 represents what appears to 
be the left outer extremity of the hyoplastron of a young individual from Hell Creek, No. 
1015 A. M. N. H. The zigzag sutural border is for articulation with the peripherals, appar- 
ently the third, fourth, and fifth. This border is only 2 mm. thick. The longitudinal sulcus 
is that which passes from the axillary to the inguinal notch. The short branch on the right 
appears to be the pectoro-abdominal. The three scute areas on the left may be inframarginals 
or they may be marginals. If inframarginals, they extend wholly beyond the plastral bones. 
On the inner side of this bone is seen a portion of the strongly developt buttress which rose to 
the border of a costal, probably the first. It is possible that the bone here described really 
belongs to the inguinal region. In either case there is indicated the absence of a mesoplastron. 
On the mesoplastron of Glyptops and of Baena there is one inframarginal. There are three 
on the bone above described. There would thus be seven probably on each bridge. 

It will be seen from the descriptions given here of this species that it is very imperfectly 
known. Additional materials ought to be sought by collectors. Evidently it was a species 
that attained a considerable size and which, when grown, possest a thick shell. Its sculptured 
upper and lower surfaces must have rendered it a beautiful animal. 

Compsemys? obscura (Leidy). 
Plate 34, fig. 4. 

Emys obscurus, Leidy, Proc. Acad. Nat. Sci. Phila. 1856, p. 312; Trans. Amer. Philos. Soc, xi, i860, 
p. 153, plate xi, fig. 4.— Cope, Bull. U. S. Geol. and Geog. Surv. Terrs., lii, 1877, p. 573. 

Compsemys obscurus, CoPE, Trans. Amer. Philos. Soc, 1869, xiv, p. 124; Bull. U. S. Geol. and Geog. 
Surv. Terrs, I, No. 2, 1874, p. 30; Vert. Cret. Form. West, 1875, p. 261. — Hay, Bibliog. and Cat. 
Foss. Vert. N. A., 1902, p. 437. 

This species is retained here under the genus Compsemys because it has already been 
placed there by Cope and Leidy and because we do not know where else to place it. There is 
little evidence that it is closely related to Compsemys victa and there is no probability that 
it is an Emys, in the modern acceptation of that term. 

Leidy's type of his Emys obscurus was found by Dr. F. V. Hayden at Long Lake, in the 
present state of North Dakota, in deposits that are now regarded as belonging to the Laramie. 
The writer does not know where the type is to be found. The part figured and described by 
Leidy is a portion of a costal plate, extending from the costo-vertebral sulcus to the costo- 
peripheral suture. This costal is 33 mm. wide, 60 mm. long from the sulcus to the distal end, 
and little more than 3 mm. thick. The surface is described by Leidy as being smooth. His 
figure shows that the sutural borders were markt by fine striations at right angles to the 
sutures. 

In the American Museum of Natural History there are the proximal ends of 2 costals 
which were found by Mr. Barnum Brown, in 1902, in Laramie deposits, on Hell Creek, 
Dawson County, Montana. These are identified as belonging to the species here described. 
One of these fragments (plate 34, fig. 4) appears to belong to the second left costal. It is 31 



236 FOSSIL TURTLES OF NORTH AMERICA. 

mm. wide, 6 mm. thick at the articulation with the neural, and 3 mm. at the sutural border, 
just beyond the costo-vertebral sulcus. The proximal end is occupied by one of the vertebral 
scutes. Near the posterior border of the bone the scute overlapt the bone about 20 mm. 
The sulci are rather narrow. A broad band of fine striations borders the sutures, the striations 
being at right angles with the latter. The remainder of the surface is markt by delicate ridges 
and pits appreciable only under a lens. 

The other fragment mentioned belonged to the third or the fifth costal of one side or the 
other; and it bears a portion of the sulcus between two vertebral scutes. This sulcus extends 
along the bone a distance of 27 mm. without joining the costo-vertebral sulcus; so that we 
may conclude that the hinder vertebral scutes were somewhat wider than the anterior. 

This species is included by Cope in his list of Judith River fossils, but the writer knows 
of no specimens that confirm the statement. 

Genus ADOCUS Cope. 

Carapace firmly articulated to plastron by sutures between the bridge peripherals and the 
hyoplastrals and hypoplastrals, and by axillary and inguinal buttresses. Heads of ribs, except 
that of first costal bone, vestigial. Free borders of the peripherals acute. Scutes of the carapace 
normal; most of the marginals rising and overlapping the lower ends of the costal bones. 
Lobes of the plastron somewhat reduced; the hinder not notcht. Plastral scutes 7 pairs; the 
intergulars excluding the gulars from contact on the midline. Inframarginals present. 

Type: Emys beatus Leidy. 

The genus Adocus, as here defined, is at present known only from Upper Cretaceous 
species; and, except A. lineolatus, doubtfully referred to the genus, all are from the Upper 
Cretaceous greensand of the eastern United States. Adocus may be regarded as the least 
modified of the Dermatemydidae. Its advanct characters appear to be found in the slightly 
reduced number of neurals, one or two of the most posterior probably being usually missing; 
in the developt buttresses; in the aborted rib-heads; and in the reduced gular scutes. Prim- 
itive characters are found in the possession of seven pairs of plastral scutes and the unin- 
terrupted series of inframarginals. 

The following key may be of some value in separating the species: 

Key to Species of Adocus. 

A. Species of the Rocky mountain region; not well known lineolatus 

AA. Species of eastern United States region. 

a. Hinder lobe of plastron narrowed behind. 

h. Entoplastron wide; nearly equal to length of the suture between the hyoplastrals beatus 

bb. Entoplastron narrow; width nearly twice in the hyoplastral suture pravus 

aa. Hinder lobe broad behind; rounded or truncated. 

c. Gulo-humeral sulcus close to or crossing the entoplastron. 

d. Hinder lobe truncated behind; the length between three-fifths and 

four-fifths the width at the base punctatus 

dd. Hinder lobe broadly rounded; its length three-fifths the width at the 

base; gulo-humeral sulcus just in contact with the entoplastron. . synthettcus 
ddd. Hinder lobe broadly rounded; its length four-fifths the width at base; 

gulo-humeral sulcus well forward on entoplastron lacer 

cc. Gulo-humeral sulcus falling considerably behind the entoplastron agtlts 

Adocus punctatus Marsh. 
Plate 34, figs. 6, 7; plate 35, figs, i, 2; text-figs. 296-298. 

Adocus punctatus. Marsh, Amer. Jour. Sci. (3), XL, 1890, p. 178, plate vii, fig. 3. — ^Wieland, Amer. 

Jour. Sci. (4), XVII, 1904, p. 112, plates i-iv, text-figs, i, 2. 
Adocus beatus, Baur, Proc. Acad. Nat. Sci., 1891, p. 428. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 

1902, p. 444. 

At the present time this species is represented by better materials than any other of 
the genus, and for that reason it is here described first of all the species of Adocus. The 



DERMATEMYDID^. 



237 



in.s.l 



type belongs to the Marsh collection in Yale University Museum and presents the nearly 
complete shell. It was obtained in the upper bed of Cretaceous marl at Hornerstown, Mon- 
mouth County, New Jersey, in 1872. It has been restored and fully described by Dr. G. R. 

Wieland, as cited in the synonymy. Dr. 
Wieland's figures are employed in the pres- 
ent work to illustrate the structure. 

The total length of the carapace (plate 
35> fig- i; text-fig. 296) in a straight line is 
533 •Ti'"- The greatest width is 390 mm. 
The form is that of an elongated oval, 
broadest behind the middle, rounded in 
front, more broadly rounded behind. Dr. 
Wieland has called attention to a double 
curvature along the sides. Possibly this 
is due to slight distortion. From side to 
side anteriorly the carapace is quite evenly 
convex; posteriorly in the restoration it is 
somewhat flattened. The hinder periph- 
erals are flared somewhat upward, but the 
front ones are not. The peripherals of the 
free borders are thin and reduced to an 
acute edge. In front of the axillary notch 
the edges of the peripherals are somewhat 
reverted, leaving a groove within the edges. 
The nuchal bone is 70 mm. long on the 
midline; 65 mm. wide on the free edge; 95 
mm. where widest. There were 7 neurals, 
of which all are present except the sixth. 
Its form and dimensions are determinable 
from the surrounding bones. The seventh 
was not developt; the eighth is small. The 
table below presents the dimensions of the 
neurals. 

Most of the neurals are hexagonal, 
with the broader end forward. The first 
has the broader end behind; the second is octagonal. The absence of the seventh neural 
permitted the seventh pair of costals to meet in the midline. Those of the eighth pair also 
meet in the midline in front of the eighth neural. The single suprapygal is octagonal, 70 
mm. long and no mm. wide. 

The peripherals are in general large. Their height, at right angles with the free border, 
increases from the third to the ninth; the tenth has nearly the height of the ninth; the eleventh 
is considerably smaller. The first peripheral extends along the free border 63 mm.; and 
from this to the first costal, 65 mm. The second is slightly smaller in both dimensions. The 
third occupies 50 mm. of the free border and is 65 mm. high. The ninth is 75 mm. along the 
free edge and 103 mm. high. The eleventh occupies 62 mm. of the free border and rises 

toward the suprapygal 70 mm. The pygal measures 65 mm. 
along the free edge and is 60 mm. high. 

The sulci are usually rather narrow and shallow. Those 
on the front are somewhat deeper and broader. The table on 
page 238 gives the dimensions of the vertebral scutes. 

The costal and the marginal scutes are of unusual confor- 
mation. The anterior marginals are mostly small; the lateral and 
posterior remarkably large. As a result, most of the costals are 
considerably reduced in area. The nuchal scute is 16 mm. long 
and only 6 mm. wide. From this the marginals continue to rise 
slowly above the free border to the hinder end of fourth, which 




F1G.296. — Adocus punctatus. Carapaceoftype. X0.18. 

c.p.ifC. p.ijC.p. 8, costal plates; m.i. i, m.j. 12, marginal scutes; 
nu.p, nuchal plate; per^ 2, ptr, 11, peripheral bones; pv, 
pygal ; tpy^ suprapygal ; w. i, n. 6, neural bones. 



Neural. 


Length. 


Width. 


I 


70 


38 


2 


39 


17 


3 


S» 


40 


♦ 


47 


37 


S 


4« 


38 


6 


44 


35 


7 






8 


40 


»4 



238 



FOSSIL TURTLES OF NORTH AMERICA. 



has a height of 45 mm. All of these lie wholly on the peripherals. The fifth marginal 
suddenly rises to a height of 100 mm. and overlaps the lower ends of the second and third 
costal bones. The ninth marginal has a height of 145 mm. The next two are only slightly 

lower. The supracaudal scutes meet along the midline a dis- 
tance of 97 mm. The costal scutes diminish in size from the first 
to the last. The latter has a fore-and-aft length of 80 mm. and a 
width of 55 mm. 

The plastron (plate 35, fig. 2; text-fig. 297), as in other spe- 
cies of the genus, is relatively small. Both the anterior and the 
posterior lobes are truncated. The total length is 355 mm. The 
anterior lobe has a length of 80 mm. and a width of 175 mm. at 
the base. The truncated anterior end is 85 mm. wide. The 
entoplastron is 50 mm. long and 70 mm. wide. The bridges are 140 mm. wide. The posterior 
lobe is 130 mm. long and 175 mm. wide at the base. The posterior truncated end is about 
80 mm. wide. The free borders of both lobes are acute. The plastron articulates with the 
peripherals by means of sutures; and axillary and inguinal buttresses rise nearly to the 



Vertebral. 


Length. 


Width. 


100 


140 




95 


90 




100 


85 




98 


80 




80 


80 



'infill- 




c.p.j 



mnJJ 



Fig. 297. — Adocus punctatus. Lower side of shell. X0.16. 

ail, abdominal scute ; an, anal scute ; c. />. i, c./i. 2, etc., costal plates; «nl, entoplastron ; «/)i, epiplastron ; fern, 
femoral scute; |f, gular scute; Aum, humeral scute ; A^o, hyoplastron; /()'/>o, hypoplastron; /j^, intergular 
scute ; injnjj inframarginal scutes ; nu, nuchal bone; pec, pectoral scute; per. 3, per. 8, peripheral bones; 
py, pygal; spy, suprapygal; xiph, liphiplastron. 

lower ends of the costal bones. Plate 34, fig. 5, from a drawing made for Dr. Baur, repre- 
sents the upper side of the xiphiplastral bones. There are very distinct curved depressions 
for the pubic bones, but there was no sutural articulation of the latter bones with the plastron. 
The sutures between the various bones of the plastron are somewhat irregular, as is shown 
in the figures. The sulci are still more irregular, especially the longitudinal median. All the 
sulci are narrow and shallow. The intergulars have pushed the gulars away from contact at 
the midline, and neither gulars nor intergulars overlap the entoplastron. The humerals occupy 
42 mm. of the midline. The pectorals measure 40 mm. along the midline and they overlap the 
hinder end of the entoplastron. The abdominals, the femorals, and the anals respectively 
occupy 88 mm., 82 mm., and 72 mm. of the midline. There are 3 inframarginals on each of 
the bridges. 




DERMATEMYDID^. 239 

Both the carapace and the plastron of this species are ornamented with rows of shallow 
pits. On the carapace these pits are arranged mostly in rows that run obliquely across the 

costal, neural, and peripheral bones. On the median parts of 
the plastron the pits are less distinct, but still evidently present. 
The relationships of this species to A. beatus are discust 
under the latter species. Figs. 298 and 299, taken from Dr. Wie- 
land, represent the position of the sulci on the first left peripheral 
of A . punctatus and A. beatus. From these it appears that the 
width of the first vertebral scutes was considerably greater in the 
former than in Leidy's species; also that the free border of the 
bone itself was wider in Marsh's species than in Leidy's. As 
regards the width of the front of the vertebral scute, there is 
Fig. zgS.—AJocus punctatus. ijjfjle to be variation in it, and not much stress can be placed 

xT Mter1vidand°^ '■''''*'' °" '*• '^^^ specimen in the Philadelphia Academy which the 

writer is obliged to refer to A . lacer differs from the type in the 
arrangement of the scutes on the first peripheral. 

Adocus beatus (Leidy). 
Plate 34, figs. 6, 7; teit-figs. 299-301. 

Eviys beatus, Leidy, Cret. Reptiles, U.S., in Stnithson.Cont. Know!., xiv, 1865, pp. 107, 119, plate xviii, 

figs. 1-3. 
Adocus beatus. Cope, Proc. Acad. Nat. Sci. Phila. 1868, p. 235; Cook's Geol. New Jersey, 1868 (1869), 

p. 734; Ext. Batrach., Reptilia, Aves N. A., 1869, pp. 129, 233; Proc. Amer. Philos. Soc, xi, 

1870, pp. 296, 547; Ibid XII, 1871, p. 43; Vert. Cret. Form. West, 1875, P- 262. — Hay, Bibliog. and 

Cat. Foss. Vert. N. A., 1902, p. 444. 

The type of the present species consists of the anterior half of the first neural, the third and 
fourth neurals complete, the proximal portions of the second and third costals, the proximal 
end of the left first costal, and the left first peripheral. These were obtained in the Cretaceous 
greensand at Mullica Hill, Gloucester County, New Jersey, and were presented to the Academy 
of Natural Science of Philadelphia, by William M. Gabb. These remains are yet in the 
Academy's collection. 

In 1869 Professor Cope, as cited, identified as belonging to this species a plastron and 
some portions of the carapace which had been found in the greensand at Medford, New Jersey. 
These bones are now in the Cope collection at the American Museum of Natural History, 
at New York. A figure of this plastron is here presented (plate 34, fig. 6). Besides the 
greater part of the plastron there are present fragments of several costals, and some anterior 
peripherals. 

In 1890 Professor O. C. Marsh (Amer. Jour. Sci., XL, p. 178) described A. punctatus. 
Afterwards Dr. Baur (Proc. Acad. Nat. Sci. Phila. 1891, p. 428) affirmed that this species 
is identical with Leidy's A. beatus. Now, a comparison of Cope's specimen with the type of A. 
punctatus shows that they are without doubt of diff"erent species. At the same time, it is perhaps 
impossible to point out characters which will enable us to separate either Cope's or Marsh's 
specimens from Leidy's imperfect type. In such a case we must do one of three things — 
reject Leidy's species and its name, because of its ambiguous characters, giving a new name to 
Cope's specimen and retaining Marsh's specific name; accept Baur's conclusion, reducing 
Marsh's name to synonymy and renaming the Cope specimen; or accept Cope's determination 
and thereby avoid any new names. Cope's turtle having come from the same region and level, 
and having been first determined as A. beatus, it appears to the writer that the last of the three 
courses is the best to follow. The principal respect in which the Medford specimen differs 
from Leidy's type is in the thickness of the first peripheral. In Leidy's specimen (figs. 299, 
300) this is only 15 mm. thick, while that of Cope's is 20 mm. This does not, however, decide 
the question in favor of Baur's position, for the type of A . punctatus also has this bone 20 mm. 
thick. It is not at all improbable that the shell was thicker in some individuals than in others. 
Fig. 300 represents the same bone of Leidy's type, as the bone appears from below, showing an 
excavation for a process from the nuchal. 



240 



FOSSIL TURTLES OF NORTH AMERICA. 



Neural. 


Length. 


Width. 


Thickness. 


I 


7« 


3> 


7.3-3.1 


1 


4«? 


29? 


12 


3 


5° 


35 


11.5 


4 


46 


33 


11.5 



Marsh's type of J. punctatus and the Medford turtle have the posterior plastral lobes of 
the same width. The length of the whole plastron oi A . punctatus is 353 mm.; that of the 
Medford specimen about 420 mm. The hinder lobe of the Medford specimen (plate 34, fig. 6) 

■W is about 18 mm. longer than that of A. punctatus. It is 
also narrow and ends behind in a blunt point, while that 
oi A. punctatus is broad and the extremity is truncated. 
Plate 34, fig. 7, represents the first peripheral of the right 
side and a part of the second, while text-fig. 301 repre- 
sents the first left peripheral, all from the Medford speci- 
men. In this the front of the first vertebral scute extends 
somewhat beyond the end of the first marginal, while in 
the type (fig. 299) it does not pass beyond the marginal. 
We must, however, expect variations in this region, as there are variations in the same region 
in living turtles. The neurals of Leidy's type have the dimensions given in the table herewith. 
The thickness of the second neural is determined from the contiguous border of the costal. 

The dimensions of the remains of costals are shown in the 
table herewith. 

The anterior neural is irregularly angular in front. The 
second appears to have had the form of the same bone in the 
type oi A. punctatus. The neurals of Leidy's type are narrower 
than those of//, punctatus, but no great stress can be laid on the 
difference. Only a fragment of the first costal is present. The 
second costal articulated with the first, second, and third neurals, 
just as in A. punctatus. The first peripheral is 62 mm. antero-posteriorly, about 54 mm. 
along the free margin, and 15 mm. thick. Fig. 299, from Wieland, shows the form of this bone 
and the arrangement of the scutes on it. The neurals and costals show the regular and 
shallow pitting exhibited by A. punctatus Marsh. 

The plastron of this species is known only from the specimen described by Cope (plate 34, 
fig. 6). The dimensions may be obtained from the comparative table on page 242. The total 



Costal. 


Width. 


Thickness. 


I 
2 
3 


46-50 
62 


6 
114 

11.5 





Figs. 299-301. — Adocus heatus. Peripherals. X^. After Wieland. 

299. First left peripheral of type. 

300. First left peripheral of type, inferior surface, with section near suture with second peripheral. 

Shows pit for process of nuchal. Upper surface of section toward right. 

301. First left peripheral of Cope's Medford specimen. No. 1138 A.M.N. H. 

length may have been greater than that there given, since there is an interval wanting in the 
hyoplastron, and since less space has been allowed between the hyohypoplastral suture and 
the inguinal notch than between this suture and the axillary notch. The bridge, as restored, 
has a width of about 160 mm. The sides of the anterior lobe are only slightly convex; the front 
broad and truncated, its width being about 95 mm. The anterior border is obtuse in section. 

The hinder lobe is gradually reduced in width backward and it ends obtusely. As Cope 
remarkt, there is some asymmetry near the extremity, but this is individual. The free borders 
of this lobe are subacute and a shallow groove runs parallel with the border on the upper side 
of the bones. 

The sulci of the plastron are rather obscure. That of the median line has not been repre- 
sented in the figure. Probably it ran an irregular course, such as is seen in the other species. 
The intergular scute is large and it trespasses on the margin of the entoplastron, separating 



DERMATEMYDID^. 24I 

widely the gulars. It was probably divided. The gulars are of rather peculiar form, extending 
outward and backward toward the outer hinder angle of each epiplastron. The humero- 
pectoral sulcus is so obscure that its course is uncertain, but it appears to run where indi- 
cated in the figure. If this is correct, it did not cross any part of the entoplastron. The 
pectoro-abdominal sulcus and the abdomino-femoral are distinct and as shown in the figure. 
The course of the femoro-anal is as represented in the figure. Of the inframarginal series, 
only a small portion of one axillary scute is seen. The sculpture of the lower surface is hardly 
to be determined, the result of weathering. 

Both first peripherals are present (plate 34, fig. 7; text-fig. 301). The antero-posterior 
length is 65 mm.; the length along the free border, 64 mm.; along the hinder border, about 
half as much. The thickness, as stated, is 20 mm. The upper surface of this bone is gently 
convex; the lower surface is strongly convex antero-posteriorly. Close to the anterior border 
above there runs a shallow groove, so that the free border appears somewhat everted. On the 
lower surface the sutural face for articulation with the nuchal is excavated for the short costi- 
form process of the latter. The same excavation appears in the first peripheral of Leidy's 
type of the species (fig. 300). 

The marginal scutes did not extend upward quite half-way on the peripheral. Only a 
fragment of the second peripheral is present. The form of the nuchal bone can only be inferred 
from the sutural edges of the adjoining first peripherals. It seems probable that its right and 
left sides made a sharper angle with each other than they do in A. punctatus. It is extremely 
probable that the front border of the nuchal measured between 65 and 70 mm. The front of 
the first vertebral scute would then measure about 130 mm. 

There are present fragments of various costals and bridge peripherals. The proximal end 
of a costal, probably the left third, has a width of 50 mm. and a thickness of 1 1 mm. The 
sulcus bounding laterally the two vertebral scutes of which it bears parts is distant 25 mm. 
from the suture made with the neural. These vertebrals were then about 80 mm. wide, much 
narrower than the first vertebral. The distal end of another costal is 60 mm. wide and 8 mm. 
thick. It is crost by a sulcus which runs from 17 mm. to 45 mm. above the lower or distal end. 
A bridge peripheral is represented by the end which joined the costal. It is 57 mm. wide and 
6 mm. thick. On its inner surface is a broad, shallow groove for the extremity of the rib, and 
a portion of the rib extended beyond the border of the costal plate at least 50 mm. Another 
fragment, which appears to be part of a peripheral near one of the buttresses, indicates that a 
rib sent its free extremity down deep into the bone forming a gomphosis, as in Zygoramma. 

The costals and the peripherals are ornamented with shallow pits separated by low, 
rounded walls, and are arranged somewhat in rows. On the outer ends of the costals and 
peripherals the sculpture is often obscure. 

Adocus lacer sp. nov. 
Plate 34, fig. 8; plate 36, fig. i; text-figs. 301-307. 

The type of this species belongs to the Cope collection in the American Museum of Natural 
History. Its number is 1350. There is no history regarding the origin or the finder of the 
specimen, but there is no doubt that it was obtained from the upper greensand bed of the 
Cretaceous of New Jersey. There is nothing to indicate to what species Cope referred it. 
The materials include the greater portion of the plastron, the nuchal, the three anterior periph- 
erals of both sides and a small portion of the left front costal. 

The species is characterized by a plastron (plate 36, fig. i) which is elongated in proportion 
to the width of the base of the hinder lobe. The bridge likewise is longer, in relation to the 
width of the hinder lobe of the plastron, than in any of the other species. In width of bridge, 
in relation to the length of the plastron from the entoplastron to the rear of the xiphiplastrals, 
A. agilis exceeds it. The hinder lobe resembles most that of the species just named, but the 
lateral borders are not so uniformly curved and there is on the upper surface a groove parallel 
with the free edge. The dimensions of the various parts are to be obtained from the table 
on page 242. 

The anterior lobe is not represented in front of the hyoplastron, except by about one- 
fourth of the entoplastron. The latter has had a width of about 88 mm. The free border of 
16 



242 



FOSSIL TURTLES OF NORTH AMERICA. 



the hyoplastron in front of the axillary notch is acute, differing thus from A. agilis and A. 
beatus. The hyoplastral and the hypoplastral portions of the median suture are nearly equal 
in extent; whereas in A. agilis the hypoplastral portion is considerably longer than the hyo- 
plastral part. The transverse suture between the anterior and posterior halves of the plastron 
is very coarse, there being alternately large pits and processes for mutual gomphosial articu- 
lation. The form and proportions of the hinder lobe may be determined from the table on 
this page and from the figure. The free borders are acute, with a parallel groove on the upper 
surface. The scar for the pubis resembles that of the other species, but it is more deeply 
imprest. Just in front of the hinder border of the xiphiplastrals and lying across the midline 
there is a conspicuous elevation, the thickness of the bone here being i6 mm. In the center 
of the lobe the bone thins down to about lo mm. 

The pectoral scutes are of considerably greater extent antero-posteriorly than in A. agilis, 
68 mm. as opposed to 36 mm., the humero-pectoral sulcus swinging well forward on the ento- 
plastron. The abdominal scutes are larger than those of any of the five species compared 
with this one in the table, the sulcus between them being 135 mm. long. The femoral scutes 
also exceed those of the other related species, being 100 mm. in the midline. The anal scutes 
are relatively short, 75 mm. There are 3 inframarginal scutes on the bridge, the middle one 





Table of measurements 


of species of 


Adocus. 






A* beatus. 


A, agilis. 


A. syntheticus. 


A. punctatus. 


A. lacer. 


A. pravus. 


T^enpth of olastron 


42o± 




454 


356 




450± 


From hinder border of ento- 






plastron to rear of plastron 


34o± 


310 


346 


283 


355 




Hyoplastron on midline 


IOO± 


95 


R. 85 
L. 115 


80 


125 


no 


Width of bridge 


160 


185 


200 ± 


144 


192 




Hypoplastron on midline 


'■5 


120 


R. 147 
L. 120 


105 


120 


130 


Length of hinder lobe 


.48 


130 


'45 


130 


140 




Length of liphiplastron 


120 


100 


■■5 


100 


"5 




Width of plastron at bridge. . , 




290 


380 ^-- 


i8o 


285 




Width of anterior lobe at base 


160 


2IO± 




190 




180 


Width of hinder lobe at base . . 


>75 


177 


230 


176 


177 




Width of entoplastron 


88 


9' 


95 




88 


70 


Length of entoplastron 


54 


69.5 


70 








Thickness at crossing of med- 














ian sutures 


"4 


12 


16 




'7 


12 


Thickness of epiplastron at 














symphysis 


■5 




14 








Thickness of hyoplastron in 














front of axillary notch 


'5 


14 


■4 




14 




Thickness at front of xiphi- 














plastron in midline 


17 


16 


18 




'3 





being 107 mm. long and 28 mm. wide. In the figure the sulci are represented as being broader 
than they really are. 

The plastron is considerably eroded. The lower surface is furnisht with numerous small 
pits, some of them resembling pin-holes, but to what extent these are due to weathering it is 
difficult to say. 

The anterior rim of the carapace, from one axillary notch to the other, shows that at 
these notches the carapace had a width of 455 mm. Whether or not the carapace expanded 
backward, as it does in A. punctatus, can not now be decided. The front (plate 34, fig. 8) 
is almost exactly an arc of a circle whose radius is 197 mm. The front of A . punctatus is 
somewhat truncated. The rim is thick and heavy, except that the nuchal bone is excavated 
on its hinder surface, so that its thickness is only 14 mm. At its articulation with the first 
peripherals it has increased to 25 mm. The greatest thickness of the third peripheral, just 
in front of the axillary notch, is 40 mm. 

The upper surface of the nuchal and of the anterior peripherals is slightly convex from 
above downward. The free edge is rather thin and is somewhat reverted, as in A. punctatus. 
The lower side of the peripherals is very convex from front to back; that of the nuchal con- 
cave. The free border of the nuchal measures 75 mm. At its upper, or hinder, border it 



DERMATEMYDID^. 



243 



is 92 mm. wide. Its extent front to back is 75 mm. Its hinder border is somewhat exca- 
vated for union with the first neural. The free borders of the three anterior peripherals 
measure each from 60 mm. to 65 mm. The height of the first is 65 mm.; that of the 
third, 83 mm. 




Figs. 302-304. — Adocus lacer. Entoplastron, xiphiplastron, and peripheral. X§. 

302. Entoplastron, left half. 303. Right xiphiplastron. 304. First left peripheral. 

The sulci separating the marginal scutes from the vertebral and the costals is not 
far above the free border of the bones. If there were a distinct nuchal scute it has been 
effaced by a slight injury to the bone. The first marginal is 25 mm. from front to back. 
The ^height of the succeeding ones increases until that of the fourth is 40 mm. The first 




Figs. 305-307. — Adocus lacer. — Peripherals, xj. 

305. Ninth, tenth, and eleventh peripherals and part of suprapygal. 

306. Section near hinder end of ninth peripheral. 

307. Section of eleventh peripheral where it joined the pygal. 

vertebral scute has a width from side to side of 150 mm. It probably had the form found 
in A. punctatus. 

In the collection of the Philadelphia Academy there is a lot of bones of an Adocus which 
is referred to the present species. There are no data accompanying the specimens, but there 



244 FOSSIL TURTLES OF NORTH AMERICA. 

can be no doubt that they were found in the Cretaceous greensand of New Jersey. There 
are present the left first, ninth, tenth, and eleventh peripherals, a part of the suprapygal, 
some fragments of costal bones, the left half of the entoplastron, the left hypoplastron, and 
the right xiphiplastron. Fig. 302 represents the piece of the entoplastron. When complete 
it was 56 mm. long, 80 mm. wide, and 18 mm. thick at the hinder border. The intergular 
scutes encroacht on the front of it and the pectorals on the hinder border. The hinder lobe 
was 173 mm. wide at the base and about 135 mm. long. The left hypoplastron is 103 mm- 
long. At the midline, between the inguinal notches, it is 28 mm. thick. Fig. 303 represents 
the outline of the right xiphiplastron, seen from below. It agrees in form with that of 
the type of the species, and shows that the hinder end of the plastron was broadly rounded. 
At the middle of the suture with the corresponding hypoplastron it is 18 mm. thick. There 
was, near the outer border, a stout process that fitted into the hypoplastron. On the upper 
surface is a large depression for the pubic bone. In the midline, at the hinder ends 
of the xiphiplastra there is a considerable elevation, and here the thickness of the bone is 
20 mm. 

Both the hypoplastron and the xiphiplastron are pitted, the latter most distinctly. The 
surface of the entoplastron is irregularly pitted. 

Fig. 304 presents a view of the first left peripheral, and this may be compared with that 
o( A. heatus and that oi A . piinctatus. It measures 61 mm. along the free border and 68 mm. 
at right angles to this. Its greatest thickness, where it joins the nuchal, is 20 mm. It will be 
observed that the arrangement of the sulci differs from that of the type and resembles more 
that of A. punctatus. It is to be concluded that the scutes here were somewhat variable in 
their development. The free border of the bone is somewhat reverted, as in the type. 

The three hinder peripherals are narrow and high (fig. 305). The ninth has a width of 
65 mm. and a height of 100 mm.; the tenth a width of 60 mm. and a height of 95 mm.; the 
eleventh a width of 58 mm. and a height of 68 mm. With the latter peripheral is a portion 
of the suprapygal. Evidently, as in A. punctatus, the costo-marginal sulci ran at some 
distance above the peripherals. A part of the fifth vertebral scute appears high up on the 
suprapygal. Figs. 306 and 307 represent the hinder sutural faces of the ninth and eleventh 
peripherals. 

On the upper borders of the ninth and tenth peripherals are seen remains of the extrem- 
ities of the ribs of the seventh and eighth costals, which extend down into the peripherals. 
On fragments of the bridge peripherals are seen the rib-ends lying in shallow grooves on the 
inner surfaces, sometimes extending downward as much as 50 mm. Other fragments of 
bridge peripherals show that the transition from the upper to the lower surfaces was rather 
abrupt, there being a decided but rounded angle where the turn was made. 

The peripherals and the costals are all ornamented with pits, arranged mostly in oblique 
rows. There are about 5 pits in a line 6 mm. long. 

Adocus syntheticus Cope. 
Plate 36, fig. 2. 

Adocus syntheticus, CoPE, Proc. Amer. Philos. Soc, xi, 1870, p. 515 (name only); Ibid., p. 548; Op. 
cit., xn, 1871, p. 44; Vert. Cret. Form. West, 1875, p. 262. — Hay, Bibliog. and Cat. Foss. Vert. 
N. A., 1902, p. 444- 

Professor Cope's first reference to this species did not bear with it any description. The 
species was said to be based on a plastron lacking the entoplastron, the right epiplastron and 
the right hypoplastron, a peripheral bone from the bridge, 2 imperfect costals, and some 
smaller fragments. This type is now in the American Museum of Natural History, and has 
the number 1466. All the parts originally described are present, except the hinder extremity 
of the right xiphiplastron. The "marginal from the bridge" is a part of the right hypoplastron. 
The specimen was found in the upper bed of the Cretaceous greensand, at Barnesboro, New 
Jersey. 

Professor Cope states that the length of the plastron is 484 mm. This is probably a mis- 
print for 454 mm., which appears to be nearer to the correct length. The plastron as a whole 



DERMATEMYDID^. 245 

is broad and flat. It was truncated in front and broadly rounded behind. With only the 
known materials it is impossible to state accurately the length and width of the anterior lobe. 
The anterior, truncated end had a width of about 80 mm. The two epiplastrals joined along 
the midline for about 37 mm. The anterior free border of the epiplastral is thick, but the 
lateral border thins down backward to an edge. The size and form of the entoplastron can be 
judged from the surrounding bones. Cope gives the length as 70 mm. and the width as 95 mm., 
which dimensions appear to be correct. 

As will be seen from the plate 36, fig. 2, the sutures are extremely irregular in their course. 
The entoplastral notch in thfi hyoplastrals is not symmetrical. On account of unsymmetrical 
development, the right hypoplastron articulated with both hyoplastra, the left hypoplastron, 
and with both xiphiplastra. The right hypoplastron is thus 27 mm. longer than the left. 
These and other measurements are presented in the table on page 242. 

Professor Cope states that the length of the hinder lobe of the plastron is 155 mm.; the 
width, 230 mm. He also says that a fragment of the bridge displays the axillary and part of 
the anterior inframarginal scutes; but to the present writer this fragment seems rather to belong 
to the inguinal region of the right side. The reason for this identification is found in the fact 
that in A .punctatus and A.lacer the pectoro-abdominal sulcus starts off from the sulcus bound- 
ing the axillary scute on the mesial side, while the abdomino-femoral sulcus does not come into 
contact with the inguinal scute on the lower side of the plastron. In the fragment under con- 
sideration the arrangement of the sulci conforms to that of the region of the inguinal notch. 
On placing this fragment in this region the hinder lobe is found to have a length of 145 mm. 
and a width of 230 mm., being unusually short in proportion to the width. 

The central portion of the hinder lobe is thick, but the free borders are thin and acute, the 
thickness becoming gradually reduced. On the upper side of the xiphiplastra there is a 
prominent curved ridge, and nearer the midline a deep depression. These mark the attach- 
ment of the pubic bone. A rounded knob marks the position of the ischium. 

The fragment of the bridge which has already been referred to as belonging properly to 
the inguinal region bears on its upper, or inner, surface a strong ridge which rises to form a 
buttress against the carapace. The inner border of the buttress is sharp. There is another 
fragment of the bridge present, the outer end of the right hyoplastral. This does not reach 
so far forward as the axillary notch; backward it extends to the hyohypoplastral suture. 

The sulci of the plastron are mostly very distinct, but not broad nor deeply imprest. The 
longitudinal median sulcus runs a meandering course, but anteriorly it is too obscure to be 
traced. There was a large intergular, probably divided. Its width was about 40 mm. Its 
hinder border encroacht slightly on the entoplastron. The gulars were widely separated b\' 
the intergular. The pectorals met along the midline for about 42 mm. and overlapt slightly 
the entoplastron. The abdominals occupied 135 mm. of the midline; the femorals, about 
82 mm.; and the anals, also about 82 mm. The inframarginal scutes were large, the middle 
one about 135 mm. long and 50 mm. broad. Outside of the inframarginals are portions of 
3 marginals, the fifth, sixth, and seventh. The sixth is 137 mm. broad, running along the middle 
inframarginal for the entire length of the latter. 

The surface of the plastron is finely granulated, vermiculated, or pitted, but no definite 
pattern of sculpture can be made out. On each side of most of the sutures there is a band of 
fine parallel grooves. 

Portions of 2 costals are present, showing the proximal ends. One of these is 55 mm. wide 
at the proximal end and 8 mm. thick. On the inner surface there is seen the rudimentary 
rib-head. The other costal, probably the left seventh, is 38 mm. wide proximally, but it widens 
distaily. It is notcht proximally for a neural, probably the sixth, and behind the latter it 
apparently met the corresponding costal of the opposite side. The surfaces are smooth and 
present no distinct evidences of sulci. 

The form of the plastron of this species is most like that oi A. agilis, but it differs from that 
of the latter in being relatively shorter, in having the lateral borders more convergent from the 
base, and the bone does not thicken so rapidly from the acute free edges. The sculpture of the 
plastron of A. syntheticus is quite different from that of A. agilis, and the inframarginal 
scutes are much broader. 



246 FOSSIL TURTLES OF NORTH AMERICA. 

Adocus agilis Cope. 

Plate 36, fig. 3. 

Adocus agilis, CoPE, Proc. Acad. Nat. Sci. Phila. 1868, p. 235; Cook's Geol. New Jersey, 1868 (1869), 
p. 734; Ext. Batrach., Reptilia, Aves N. A., 1869, pp. ii, 233, 234; Proc. Amer. Philos. Soc, 
XI, 1870, pp. 296, 297, 549; Op. cit., XII, 1871, p. 44; Vert. Cret. Form. We.st, 1875, p. 262. — Hay, 
Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 444. 

The type of this species is in the American Museum of Natural History and bears the 
number 1135. It was collected in the upper bed of the Cretaceous greensand of New Jersey, 
at Barnesboro. 

The only portion of the animal represented is the plastron (plate 36, fig. 3) and this is not 
complete. Cope states in his description that the extremities of both lobes are broken off; but 
at present the hinder lobe is complete on the right side. The front of the anterior lobe being 
gone, the total length of the plastron can not be determined with exactness. Cope estimated it 
at 450 mm.; but this is certainly an error; it was probably not greater than 400 mm., and 
more probably about 390 mm. 

The plastron is short and broad, but yields in these respects to that of A. punctatus. The 
dimensions may be obtained from the table on page 242. The plastron is very flat, even out to 
the suture with the peripherals of the bridge, but it is possible that the bridge has been distorted 
through pressure. The entoplastron has its anterior angle now broken off, but Cope gave its 
length as 69.5 mm. Its width is 91 mm. The free edge of the hyoplastron, just in front of the 
axillary notch, is rounded in section. The bridge is, relatively to the length of the plastron 
behind the entoplastron, longer than in any species with which it is compared on page 242. 

From the inguinal notch the free borders of the hinder lobe curve gradually to the midline 
behind. These borders are acute, and from them the bone thickens rather rapidly and without 
the intervention of a groove on the upper surface. The center of the lobe has no depression 
such as we find in A. lacer and to a less extent in A. beatus. On the hinder half of.the upper 
surface of each xiphiplastron there is a large curved depression which marks the place of 
articulation of the pubis. It is not so deeply imprest as it '\s\n A . lacer. 

Cope gave, as one character separating this species from the others then described, the 
thinness of the bones; but they appear to be only a little thinner than those of A. beatus. 

The hyoplastron just behind the entoplastron is 13 mm., that oi A. beatus, 14 mm.; just 
in front of the axillary notch, 14 mm., that of//, beatus, 17 mm.; medially at the front of the 
xiphiplastron, 16 mm., in A. beatus, 17 mm. 

The humero-pectoral sulcus falls behind the entoplastron. The abdominal scutes meet 
along the midline for a distance of 105 mm.; the femorals, 87 mm.; the anals, 76 mm. The 
inframarginals on the bridge are long and narrow, the middle one being 80 mm. long and 
16 mm. broad. The median longitudinal sulcus runs a very irregular course, especially in the 
hinder half of the plastron. 

The whole lower surface of the plastron is ornamented with a sculpture which consists 
of very shallow, somewhat elongated depressions separated by low rounded walls. The pits 
alternate somewhat and are arranged more or less in rows. These run usually in a longitudinal 
direction. The sculpture is much like that of A. beatus and A. punctatus, and reminds us of 
Cope's description of that of Basilemys imbrtcarta, but the pits are not nearly so deep as in the 
latter species. 

Adocus pravus Leidy. 

Emys pravus, Leidy, Proc. Acad. Nat. Sci. Phila. 1856, p. 303; Smithson. Contrib. Knowl., xiv., art. 

vi, 1865, pp. 108, 120, plate xix, fig. i. 
Adocus pravus. Cope, Proc. Acad. Nat. Sci. Phila. 1868, p. 235; Cook's Geol. New Jersey, 1868 (1869), 

p. 734; Ext. Batrach., Reptilia, Aves N. A., 1870, pp. 129, 233, 234; Proc. Amer. Philos. Soc, 

XI, 1870, p. 297; Ibid., xii, 1871, p. 44; Vert. Cret. Form. West, 1875, p. 262. — Hay, Bibliog. and 

Cat. Foss. Vert. N. A., 1902, p. 444. 
Emys parva, Maack, Palaeontographica, xvill, 1869, p. 278. 

The present species was discovered by Professor George H. Cook, State Geologist of New 
Jersey, in the upper bed of Cretaceous greensand at Tinton Falls, Monmouth County, New 
Jersey, and was described by Dr. Joseph Leidy. Originally the type consisted of most of the 



DERMATEMYDID^. 247 

left hyoplastron, a large part of the right hypoplastron, and the hinder ends of both xiphi- 
plastra. Of these, there is now in the collection at Rutgers College only the hyoplastron. 

The species is characterized by the thinness of the bones, being approacht in this respect 
only by A. agilis. The hyoplastron has a thickness varying from lo mm. to 12 mm. Accord- 
ing to Leidy the hypoplastron varies in thickness from 10 to 14.5 mm. 

From the portion of the hyoplastron present it appears that the width of the anterior lobe 
at the base was about 180 mm. The hyoplastral bones joined along the midline a distance of 
about no mm. The entoplastron had an approximate width of 65 mm. and extended back- 
ward behind the hyoepiplastral sutures about 40 mm. A sulcus, the humero-pectoral, crosses 
the plastron 7 mm. behind the entoplastron and is directed slightly backward on its way out- 
ward. The free border of the lobe is subacute. All the sutures of the hyoplastron appear to 
have been close and smooth when viewed from below; but, seen from above, they were coarse 
and jagged. 

The hypoplastra are stated by Leidy to have extended along the midline 5 inches; accord- 
ing to his figure, 130 mm. The hinder end of the plastron appears to have been narrowed, as 
in A . beatus. 

This species seems to have most resembled A. agilis; but the entoplastron of the latter is 
considerably broader, less abruptly rounded, and the notch was more open. In A. syntheticus 
and A . punctatus the humero-pectoral sulcus crosses on the entoplastron. 

This species differs from Cope's specimen oi A . beatus, from Medford, in having a narrower 
entoplastron. In the latter the width of this bone was about equal to the length of the suture 
between the right and left hyoplastra. In A. pravus the width was equal to only two-thirds 
the suture between the hyoplastra. In other respects the two species, so far as known, appear 
to agree. Altho Leidy has restored in outline the anterior lobe of A. pravus as being very 
narrow, it may in reality have been much broader. 

Adocus? lineolatus Cope. 

Figs. 308, 309. 

Adocus? lineolatus. Cope, Bull. U. S. Geol. and Geog. Surv. Terrs., i, No. 2, 1874, p. 30; Ann. Report 

U. S. Geol. and Geog. Surv. Terrs., 1873 (1874), p. 454; Vert. Cret. Foim. West, 1875, p. 

92. — Lambe, Contrib. Canad. Palaeont., in (410), 1902, p. 38. 
Adocus lineolatus. Cope, Vert. Cret. Form. West, 1875, p. 263, plate vi, figs. 11, 12. — Hatcher, Bull. 

U. S. Geol. Surv. No. 257, 1 905, p. 75. 
Compsemys lineolatus, CoPE, Bull. U. S. Geol. and Geog. Surv. Terrs., Ill, 1877, p. 573. — Hay, Bibliog. 

and Cat. Foss. Vert. N. A., 1902, p. 437. 

Of the present species very little is known. The name is based on 2 fragments which were 
collected by Professor Cope, in northeastern Colorado. From Whitman Cross (Monogr. U. S. 
Geol. Surv., xxvii, 1896, p. 244) we learn that Cope communicated the fact that these and 
some other fossils had been collected at some point not designated on Bijou Creek. 

Cross is of the opinion that these fossils came from what are called by him the Arapahoe 
beds, a formation overlying the Laramie. Cope's type of his Adocus? lineolatus is now in the 
American Museum of Natural History and has the number 1844. Cope's figures represent 
well the specimens; but since they have been figured the surface has been scraped from the 
neural, so that its sculpture no longer appears. That of the fragment of plastron remains. It 
is obscure, but consists of elongated, very shallow pits, four or five in a line 5 mm. long, and 
arranged more or less in rows and separated by low narrow ridges. The neural has a maxi- 
mum width of 28 mm. and a thickness of 7 mm. The plastral bone is 8 mm. thick at the 
sutural border. This suture is coarse and, as Cope says, has a median serrate keel, with pits on 
each side of it for the reception of processes from the bone with which it articulated. 

Cope stated that the species comes also from the mouth of the Big Horn River, but the 
present writer does not know of any specimens on which this identification was based. Cope 
likewise includes the species in his list of Judith River species. Lambe, as cited, reports it 
from the Belly River beds on Red Deer River, Alberta, British America. His specimens too 
were fragmentary. Specimens with a sculpture very similar have been brought to the American 
Museum of Natural History from the Laramie beds of Montana. These were collected by 



248 FOSSIL TURTLES OF NORTH AMERICA. 

Mr. Barnum Brown, on Hell Creek, Montana. Fragments of costals scarcely, if at all, to 
be distinguisht from them are found in the collection made in the Judith River region for 
Professor Cope, by C. H. Sternberg, in 1876. It is the writer's opinion that it is unsafe to 
identify as belonging to Adocus lineolatus specimens from the Judith River and the Laramie 
beds before far better materials of the species have been collected from the type locality. And 
when these better materials have been secured from Bijou Creek, better specimens than yet 
obtained must be secured from the other formations mentioned. It is improbable that the 
same species continued from the Judith River epoch to the Arapahoe epoch. Meanwhile, 
even good fragments are worth preserving. 

The specimen referred to above as having been collected by Sternberg from the Judith 
River region forms No. 6105 of the American Museum. It belonged to the third or the fifth 
costal. Its width is 32 mm.; its thickness, only 3.5 mm. There is no thickening along the 
middle on the under side corresponding to the rib. The outer surface is crost by the costo- 
vertebral sulcus. The ornamentation resembles in pattern that of Cope's Compsemys im- 
bricaria {Basilemys imbricaria), and Cope has so labeled the bone; but the size of the areolae is 
considerably smaller, there being 4 pits in a line 5 mm. long, instead of 3 or less. The ridges 
between the areolae are low and run at right angles with the sutural borders of the bone. 

A fragment of a costal from Hell Creek, Montana, collected by Mr. Barnum Brown, is 
catalogged under the number 1014 of the American Museum. The costal is 36 mm. wide 
and 5 mm. thick . The sculpture is similar to that of the Judith River specimen just 
described, but is more obscure. 

A peripheral, the second of the left side, has the number 1014, but it belonged to a much 
larger individual. It is represented by figs. 308 and 309. The bone is 55 mm. high, 48 mm. 

along jthe free border, and 32 mm. along the 
costal border. Fig. 309 represents the border 
joining the first peripheral, the greatest thick- 
ness being 16 mm. The sutural border for the 
third peripheral has a maximum thickness of 
309. 24 mm. The sculpture has the pattern and the 
fineness ascribed to the costal. It resembles 
greatly that of the fragments numbered 6103 

f.^o „Q .„,.,«^ J J r It, P„,:.,i, A. M. N. H. and described under Basilemys 
r IGS. 300 AND 309. — Adocus Itneolatus. reripn- ... -' 

eral and section. Xj. No. 1014 A. M. N. H. tmbricarta. 

No. 6107 A. M. N. H. includes a fragment 

308. Second left peripheral ^f ^ ^^^^^j j^^^ ^^^ another of a plastral bone 

305. Section of same peripheral at union with third. » ^ r n r A -o 

which were collected for Professor Cope, m 1877, 
by Mr. J. C. Isaac, in the Laramie of Converse County, Wyoming. The sculpture of these 
bones resembles closely that of ^. lineolatus, type. 

Genus AGOMPHUS Cope. 

Shell thick and heavy in the known species. Free borders of the carapace thickened and 
obtuse. Exposed surfaces of the shell not pitted. Hinder marginal scutes not rising on the 
costal bones, except slightly in one species. Inframarginal scutes present. The pectoral 
scutes extending forward to the hinder end of the epiplastrals. Intergulars not known. Nuchal 
with costiform processes. Rib-heads more strongly developt than in Adocus. 

Type: A gomphus turgidus Cope. 

The genus Agomphus was founded by Cope in 1871 (Proc. Amer. Philos. Soc, xii, p. 46) 
having A. turgidus as the type. The only character given was the apparent lack of gomphosis 
between the costals and the peripherals; an insufficient character, if a true one. In 1882 
(Proc. Amer. Philos. Soc, xx, p. 145) Cope placed Agomphus with Dermatemys in the Emy- 
didas, characterizing it as possessing 2 anal marginal scutes, a series of inframarginals, and 
with the lobes of the plastron wide. The same views are repeated in that author's Vertebrata 
of the Tertiary Formations of the West, in 1884. In both the publications referred to, the 
genus Amphiemys was placed among the Adocidae. Baur in 1888 (Zool. Anzeiger, XI, p. 595) 
reduced Amphiemys to the position of a synonym of Agomphus and arranged the latter under 




dermatemydidj*. 249 

the Adocidae. In 1891 (Proc. Acad. Nat. Sci. Phila., p. 429) Baur retains Agomphus in the 
Adocida; and gives as its distinguishing characters the narrow lobes of the plastron and the 
shorter bridge. He states too that it has costiform processes which reach the second peripheral, 
piercing the first. 

The general term of the shell of the species of this genus is indicated by that of A. tardus 
Wieland. 

Key to the Species of Agomphus. 

A^. Upper Cretaceous species. 

a'. With the costo-peripheral sulci, so far as known, confined to the peripheral bones. 

1. Plastron nearly flat transversely; entoplastron broadly rounded behind; pectoro- 

abdominal sulcus much nearer the hyohypoplastral suture than to entoplastron; 
costo-marginal sulci above middle of peripheral bones; costal border of peripherals 
much thinner than maximum thickness turgidus 

2. Plastron strongly convex transversely; costo-marginal sulci below middle of periph- 

erals petrosus 

3. Like petrosus, but plastron not so convex ; costo-marginal sulci above middle of 

peripherals; costal border of peripherals not much thinner than maximum thick- 
ness tardus 

4. Entoplastron pointed behind; pectoro-abdominal sulcus nearer hyohypoplastral 

suture than to entoplastron ; suture between the hyoplastra 0.25 of the hyohypo- 
plastral suture pectoralis 

5. Entoplastron truncated behind; pectoro-abdominal sulcus nearer entoplastron than 

to hyohypoplastral suture firmus 

a^. Costo-peripheral sulci of nth and 12th marginal scutes rising above the peripherals. 
I. Entoplastron pointed behind; suture between hyoplastrals 0.35 of the hyohypo- 
plastral suture masculinus 

A^. Early Tertiary species. 

I. With hinder lobe of plastron much narrowed behind oxysternum 

Agomphus turgidus Cope. 
Plate 37, figs. 1-5; teit-fig. 310. 

Emys turgidus, Cope, Ext. Batrach., Reptilia, Aves N. A., 1869, pp. 125, 127. — .?Wieland, Amer. 

Jour. Sci. (4), XX, 1905, p. 440, fig. 9, in part. 
Agomphus turgidus. Cope, Proc. Amer. Philos. Soc, xil, 1871, p. 46; Vert. Cret. Form. West, 1875, p. 

262. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445. 

This species, the type of the genus Agomphus, is based on portions of the skeleton which 
were obtained from the upper greensand bed of the Cretaceous of New Jersey. The materials 
consist of both hyoplastra somewhat damaged; the entoplastron; the fourth neural; the 
proximal ends of the third, fourth, fifth, and sixth costals of the left side, and of the third, fourth 
and sixth of the right side; some fragments representing the distal ends of costals; and four 
peripherals, one from the bridge. The specimen is now in the Cope collection in the American 
Museum of Natural History, and bears the number 148 1. 

The portion of the plastron (plate 37, fig. i) preserved has been considerably eroded. 
The epiplastrals being gone, nothing is known regarding the form of the front of the plastron. 
The front lobe had a width of 90 mm. at the base. The free border, as far as represented, is 
thin and rounded in section, and a shallow groove runs parallel with it on the upper side. 
Toward the midline the bone thickens rapidly, and at the hinder border of the entoplastron it 
is 14 mm. thick. This increases to 17 mm. at the crossing of the median longitudinal and 
transverse sutures. The entoplastron is rather pointed in front, broad and rounded behind. 
It is slightly broader than long, thin in front (6 mm.) and thick behind (14 mm.). 

The transverse suture behind the hyoplastrals is somewhat irregular in direction. The 
denticulations are fine, but there are some grooves and keels near the midline. 

Professor Cope states that only the longitudinal median sulcus is to be made out. Yet to 
the present writer it seems clear that there is one which crosses the entoplastron, the humero- 
pectoral, and another which crosses the hinder ends of the hyoplastrals, the pectoro-abdom- 
inals. These are in exactly the positions of the corresponding sulci in A. pectomhs. The 



250 FOSSIL TURTLKS OF NORTH AMERICA. 

surface of the plastron appears to have been somewhat uneven, but no definite pattern of 
sculpture can be made out. 

The fourth neural (plate 37, fig. 5) has a length of 27 mm., a width of about 24 mm., and 
a thickness of 11 mm. The costals at the proximal ends are as thick as the neurals, but they 
rapidly become thinner, so that at a distance of 30 mm. from the neurals a costal is only 5.5 mm. 
thick; and this thickness is maintained to the distal ends. The capitula of the ribs are well 
developt. The sulci limiting laterally the vertebral scutes are deeply and sharply imprest. 
These vertebral scutes were rather narrow, about 43 mm. wide. The third vertebral has a 
length of 60 mm. The surface of the bone is finely striated longitudinally. 

Plate 37, fig. 4, represents 3 peripherals which appear to have had the positions assigned 
to them, the eighth, ninth, and tenth of right side, but possibly the ninth, tenth, and eleventh. 
The one seen on the right of the figure is the anterior, but it did not articulate with the 
hypoplastron. Each has an extreme thickness of about 11 mm. The exterior surface is con- 
cave vertically, while the inner surface is strongly convex. Fig. 310 is a section through the 
middle one of the three. Altho the free edge of the series is somewhat eroded, it evidently was 
rounded. Further forward this edge appears to have been more angulated, until, as represented 
by one of the bridge peripherals, the upper side of the shell made abruptly an angle of about 
45° with the lower side. The marginal scutes of this species were confined to the peripheral 
bones, instead of extending upward on the costals. As shown in the figures, the costal scutes 
come down well on the peripherals. 

The carapace of this species had a length of about 265 mm. 

In the Cope collection at the American Museum there is a pair of hyoplastrals. No. 1479 
(plate 37, fig. 2), which evidently belongs to this species and which is labeled as having been 

found at Mount Holly, New Jersey, in 1870. It has the size of 
the corresponding bones of the type, but it is considerably 
thicker, being 20 mm. just behind the entoplastral notch and 
also at the hinder border of the bones near the midline. About 
one-third the distance from the notch toward the rear the thick- 
ness is 22 mm. This specimen displays the pectoro-abdominal 

. , ■ , sulcus and a portion of the inframarginal scutes on the left 

riG. 710. — Asompnus turgiaus. -jt-ii ^lu j ■ j ^ 

„ -^ . * '^ . , * . , side. The latter appear to have been arranged as m A. pec- 

bection across ninth periph- ,. _,, i- 1 • 1 1 1 l 

eraloftvpe Xj torahs. The median sulcus is obscure, but what appears to be 

a portion of it is seen on the right side running backward 

from the transverse sulcus, while apparently another short branch is seen on the left side. 

The surface of the plastron contains several large shallow pits and long grooves, as shown 

in the figure cited. It is evident that these have been made during the life of the animal, the 

result probably of some disease. Fig. 3 of plate 37 represents the same hyoplastrals seen from 

the front. 

Agomphus petrosus Cope. 

Plate 36, fig. 4; plate 37, figs. 6, 7; text-figs. 311-313. 

Adocus petrosus. Cope, Proc. Acad. Nat. Sci. Phila. 1868, p. 236; Cook's Geol. New Jersey, App. B, 

1868 (1869), p. 734; Proc. Amer. Phiios. Soc, xi, 1870, p. 295. 
Emys petrosus, CoPE, Ext. Batrach., Reptilia, Aves N. A., 1869, pp. 125, 126. 
Agomphus petrosus. Cope, Proc. Amer. Phiios. Soc, xii, 1871, p. 46; Ann. Report U. S. Geol. Surv. 

Terrs., 1872 (1873), p. 625; Vert. Cret. Form. West, 1875, p. 262. — Hay, Bibliog. and Cat. Foss. 

Vert. N. A., 1902, p. 445. 

The type of this species is now a part of the Cope collection in the American Museum of 
Natural History in New York. It consists of a portion of the right hyoplastron; 5 peripheral 
bones, with perhaps a fragment of another; portions of four costal bones; a fragment of the 
right hypoplastron; and what Cope regarded as the head of the coracoid, but which seems to 
be rather the articular end of the pubis. These have been catalogged under the number 
1482. They were collected from the upper greensand bed of the Cretaceous, at Gloucester, 
New Jersey. 

The plastron (plate 36, fig. 4) was not flat below like that of the species of the other 
species of Agomphus, but very convex. Cope states that the curvature from the peripherals 




DERMATEMYDIDiE. 25 1 

of one side to those of the other amounts to 124°. Unfortunately the free border of the front 
lobe has not been preserved, so that it is impossible to determine the width of the lobe at the 
base; but it could not have been far from 100 mm. The notch for the entoplastron shows that 
this bone had a width of 42 mm. It appears to have been broadly rounded behind. While 
the thickness at the hinder border was about 17 mm., it was much thinner at the front. The 
thickness of the hyoplastron a short distance behind the entoplastron is 20 mm.; at the hinder 
border of the hyoplastron in the midline, 15 mm.; at the articulation with the fifth peripheral 
10 mm. The bone is therefore very thick and its tissue is dense and heavy. 

There is present a fragment of the free border of the hypoplastron, including a portion of 
the sutural border for the xiphiplastron. At a distance of 28 mm. from the free border the bone 
is 18 mm. thick. This continues to within about 20 mm. of the border, and then the bone is 
rapidly beveled off to a blunt edge. The lower surface of the bone curves upward to meet the 
bevel. 

The surface of the hyoplastron and of the fragment of the hypoplastron is very smooth, 
having apparently been polisht during the life of the animal. The proximal end of the first 
costal is preserved. Its neural border is concave for the first neural. Its hinder angle joined 
the second neural. Here the bone is 12 mm. thick. In front it is 8 mm. thick. On the under 
side are seen the base of the rib-head and articulation for the first rib. 

Two adjacent costals of the right side (plate 37, fig. 7), the fourth and the fifth, or the 
fifth and the sixth, are present. They are each 45 mm. in width at the proximal end. At the 
suture with the neurals they are 16 mm. thick; at a distance of 60 mm. from the neurals one 
has still a thickness of 9 mm. The capitula of the ribs are moderately developt. Little or no 
trace is left of the rib on the inner side of the costal plates. These costals are considerably 
archt, showing that, with the curvature of the plastron, the shell was high and vaulted. 

Figs. 311-313. — Agomphus petrosus. 
Peripherals of type. Xj. 

311. Section at anterior end of second peripheral. 

312. Section at anterior end of supposed eighth 

peripheral. 

313. Section across supposed first peripheral of 

left side. 

Two anterior peripherals (plate 36, fig. 4), the second and the third of the right side, are 
connected with the outer anterior angle of the hyoplastron. They are thick and massive. 
The free edge ot these peripherals is rounded like the edge of one's hand, and at the anterior 
end of the second the border is slightly everted. Fig. 311 represents a section taken at this 
point. The thickness here is 15 mm. The second peripheral is 40 mm. in length along the 
free border and 40 mm. high. The third is 50 mm. long. The hinder border of the latter 
peripheral and the anterior lateral process of the hyoplastron furnish the articular border for 
the fourth peripheral; while behind this is a part of the articular border for the fifth periph- 
eral. Two of the hinder peripherals (plate 37, fig. 6), supposed by Cope to have been the 
eighth and the ninth, are at hand. The supposed eighth did not articulate with the hypoplas- 
tron as it appears to have done in Wieland's A. tardus and may therefore be the ninth. The 
fragment of costal attacht to it appears to be the fifth, since on it there is no trace of a descend- 
ing sulcus. These, with the distal end of the fifth costal, are figured on plate 37. Fig. 312 
presents a section across the anterior end of the supposed eighth. The free borders of these 
peripherals are thick and rounded like those of the anterior peripherals. The greatest thickness 
of the eighth is 20 mm.; but where the bone articulates with the costal the thickness is reduced 
to 6 mm. The ninth peripheral has the border considerably flared upward and more acute than 
further forward. Accompanying the type is another peripheral (fig. 313) which Cope has 
labeled as the first of the left side. On one side there is an excavation, as if for the nuchal. 
However, there are difficulties in regarding it as the first peripheral of this species One of 
these is the great thickness of the bone where it would come in contact with the second periph- 
eral, being 19 mm., whereas the corresponding border of the second peripheral of the right 
side is only 16 mm. thick. Again, as the upper surface approaches the free border, it curves 




252 



FOSSIL TURTLES OF NORTH AMERICA. 



downward; whereas, the border of the second peripheral is turned upward. It is probable 
that the bone is an intrusion from another species. 

The sulci of the plastron are wholly effaced. On the costals they are narrow, but distinct. 
As seen from plate 37, fig. 7, the sulci limiting the vertebral scutes laterally are not far removed 
from the costo-neural sutures. The first vertebral was evidently wider than those succeeding 
it. If the neurals had the relative width that they have in Adocus punctntiis, the third vertebral 
must have been 52 mm. wide. On the second and third peripherals the longitudinal sulci 
lie not far above the free border of the carapace. The sulci on the supposed eighth and ninth 
peripherals are so obscure that they can not be traced. 

Agomphus tardus Wieland. 

Test-figs. 314-318. 

Agomphus ttii Jus, Wielaud, Amer. Jour. Sci. (4), xx, 1905, p. 430, figs. 1-7. 

This species was found in the Cretaceous marl pits at Birmingham, Burlington County, 
New Jersey, in 1869. The type forms number 774 of the Marsh collection at Yale University. 
The parts recovered are most of the nuchal, the second and the fifth neurals, the first and 
second left costals; fragments of the third and fifth, and the whole of the eighth right costals; 
of the right peripherals, the first, eighth, ninth, and tenth; of the left side the fifth, sixth, tenth, 
and the eleventh; the left hyoplastron, and the right hypoplastron. These parts have enabled 




314- 




pern 



xiph 315. 



Figs. 314 and 315. — Agomphus tardus. Carapace of type. 



3'4 



Sections at anterior ends of peripherals indicated by the numerals. Xg. c, in first peripheral, pit for pro- 
cess of nuchal, s, in eighth peripheral, sutural border for union with hypoplastron; /Jy, section of pygal. 
315. Shell seen from left side. X0.23 c. p. i, etc., costal plates; epi, epiplastron; Ayo, hyoplastron; hypo, hypo- 
plastron; nu./>, nuchal plate; ^fr. i, ^er. 2, etc., peripheral bones; at/^A, liphiplastron. 

Dr. Wieland to restore satisfactorily the form of the shell. A number of his figures are here 
reproduced. 

The bones of this species were even thicker and heavier than in A . petrosus. The shell 
(figs. 314-318) was elongated and rather high. Prom the highest point the carapace sloped 
gently to the front, while the rear sloped rapidly downward. The length of the carapace was 
about 330 mm.; the greatest breadth, about 230 mm. The nuchal bone is 53 mm. long and 
52 mm. wide along the free margin. It is 13 mm. thick near the free margin and 7 mm. thick 
posteriorly. The second neural has a length of 40 mm., an extreme width of 35 mm., and a 
thickness of 14 mm. The fifth neural is 40 mm. long, 36 mm. wide, and 15 mm. thick. As 
in A . petrosus, the first costal attains considerable thickness at the junction with the second 
and third peripherals, being here 22 mm. thick. The rib-heads are diminutive. All the 
peripherals are very obtuse at their free borders. Fig. 314 shows the form of the anterior end 
of the first, the second, the eighth, the ninth, the tenth, and the eleventh peripherals, as well 
as of the border of the pygal that joins the eleventh peripheral. It will be observed that the 
thickness of the first and the second near the middle of the height is maintained to the costal 
border. 

The nuchal scute is moderately broad. The sulci bounding the vertebrals and the costals 
have not been observed. The costo-marginal sulci run along on the upper half of the periph- 
erals, without at any time reaching the costal bones. 



dermatemydiDjS:. 



253 



The entoplastron is not present, but the notch in the front of the hyoplastron shows that 
the entoplastron was broadest behind. Its width was about 45 mm. The hyoplastron (fig. 
318) is 60 mm. long on the midline and about lOO mm. wide. Its greatest thickness, at the 
midline, is 27 mm. Laterally it thins to about 9 mm. The hypoplastron is 62 mm. long on 

the midline, 95 mm. wide, and 31 
mm. thick. The bridge was about 
106 mm. wide. 

No sulcus has been observed 
crossingthe front of the hyoplastron 
and the entoplastron. The pectoro- 
abdominal crosses in front of the 
hyohypoplastral suture, as in A. 
petrosus. The abdomino-femoral 
sulcus swings well forward on the 
hypoplastrals. So far as observed, 
there is only an axillary inframar- 
ginal and behind it a single addi- 
tional scute. It seems probable 
that the latter will be found to 
have been subdivided. 




perl 



xiph 



Fig. 316. — Agomphus tardus. Shell of type, seen 
from right side. X0.23. Lettering with same 
signification as in Fig. 315. 



This species appears to differ from A. petrosus, its closest ally, in the following respects: 
The marginal scutes extend higher on the peripheral bones; the second peripheral is relatively 
higher; this peripheral of A. tardus is not so thick near the free border, but thicker at the upper 

317- 318. 
.^per.l 
yper.2 

per. Z-'-f. 





per. 6 



Figs. 317 AND 318. — Agomphus tardus. Shell of type. X0.23. 

317. Carapace, seen from above, c.p.i, c./).8, costal plates; n. i, «.8, neural bones; nu. p, nuchal bone; 

pfr. I, /ler, II, peripheral bones; py, pygal; s/))', suprapygal. 

318. Shell, seen from below, ab, abdominal scute; an, anal scute; epi, epiplastron; ent, entoplastron; fem, 

femoral scute; Ajo, hyoplastron; Av/'o, hypoplastron; /)ff, pectoral scute; /)fr. 2, /ifr. 6, />(?r. 1 1, peripheral 
bones; j:(/)A, liphiplastron. 

border than in A. petrosus; the third peripheral is not so long (38 mm.) as it is in A. petrosus (45 
mm.); the upper, or costal, borders of A. tardus are thicker and the outer end of the hyo- 
plastron has not so strong an upward curve as in A. petrosus. 

From A. turgidus this species differs in having the peripherals nearly as thick at their 
costal borders as the maximum thickness. 



254 



rOSSII. TURTLES OF NORTH AMERICA. 



& 



Agomphus pectoralis (Cope). 
Plate 37, figs. 8, 9. 

Pleurosternum pectorale. Cope, Proc. Acad. Nat. Sci. Phila. 1 868, p. 236; Cook'.s Geol. New Jersey, App. 

B, 1868 (1869), p. 734; Ext. Batrach., Reptilia, Aves N. A., 1869, p. 130. 
Adocus pectoralis. Cope, Batrach., Reptilia, Aves N. A., 1869 (1870), pp. ii, 233, plate vii, fig. i; Proc. 

Amer. Philos. Soc, xi, 1870, pp. 296, 548; Proc. Amer. Philos. Soc, xii, 1871, p. 43; Vert. Cret. 

Form. West, 1875, p. 262. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 444. 

The first mention of this species, under the name Pleurosternum pectorale, occurs in the 
Proceedings of the Academy of Natural Science, Philadelphia, 1868, page 236, in the de- 
scription of Agomphus petrosus. This mention may be regarded as sufficient to fix the date 
of the species, altho the description is very brief and only incidental. Under the same name a 
full description and a figure were publisht in 1869, in the author's work. Synopsis of the 
Extinct Batrachia, Reptilia and Aves of North America. In a part of the same paper issued in 
1870, the species was assigned to the genus Adocus. To the present writer the species appears 
to belong to Agomphus. 

Agomphus pectoralis is up to the present time known to us by only the type specimen, 
which consists of both hyoplastral bones (plate 37, figs. 8, 9). These are now in the Cope 
collection, in the American Museum of Natural History, in New York, and they have the 
catalog number 1478. The specimen was found in the upper bed of the Cretaceous green- 
sand, near Medford, New Jersey. These hyoplastrals are complete, extending from the 
sutures for the bridge peripherals of one side to those of the other. The width from side to 
side is 146 mm. The free borders of the anterior lobe pass by a broad curve into the axillary 
notch, making it difficult to determine accurately the width of the front lobe at the base. It 
may be regarded as about 85 mm. 

The free borders of the epiplastrals are subacute, and from them the bone thickens 
gradually to the median longitudinal suture. At the hinder angle of the entoplastron the 
thickness is 15 mm.; at the hinder border of the hyoplastrals, in the midline, the thickness is 
20 mm. Where these bones have joined the peripherals of the bridge, they are only8 mm. thick. 

The hyoplastrals are deeply notcht for the reception of the entoplastron. This is pro- 
longed further backward than in the other species of the genus. The axillary notches, too, are 
very deep and narrow. Outside of each notch the hyoplastron sends upward and forward a 
strong process, or buttress, against the carapace. Inwardly this forms a sharp crest. 

The dermal scutes of this species differ considerably from those of the species of Adocus. 
Professor Cope thought that there had been a fusion of the humeral and the pectoral scutes, 
and that the sulcus seen crossing the extreme anterior end of the left hyoplastron was the 
posterior boundary of the gular scute. It seems more probable, however, that this sulcus 
represents the posterior limit of the humeral. This interpretation throws the humero-pectoral 
sulcus indeed far forward, but it is little more so than it is in Dermatemys mawii (Boulenger, 
Cat. Chelonians, p. 28, fig. 8). On the outer ends of the hyoplastrals there are represented 
three inframarginals. The axillary is small and, outside of the notch, extends well forward. 
The second inframarginal is hexagonal and represents the hinder end of the axillary oi Adocus 
punctatus. The third inframarginal rested principally on the hypoplastron. In Alamosemys 
suhstricta the arrangement is somewhat as in the species here described. The whole arrange- 
ment of the scutes resembles closely that oi Dermatemys mawii, and there is little in the species 
as known to exclude it from that genus. The species is here referred to the genus Agomphus 
because of its close resemblance to A. turgidus. Only specific differences are observable. 

Agomphus firmus (Leidy). 

Emys firmus,hEiDY, Proc. Acad. Nat. Sci. Phila. 1856, p. 303; Smithson. Contrib. to Knowl., xiv, 1865, 

p. 106, plate xix, figs. 2, 3. — Cope, Ext. Batrach., Reptilia, Aves N. A., 1869, pp. 126, 127. — 

Maack, Palasontographica, xviii, 1869, p. 277. 
Adocus firmus, CoPE, Proc. Acad. Nat. Sci. Phila. 1868, p. 235; Cook's Geol. New Jersey, 1868 (1869), 

p. 734; Proc. Amer. Philos. Soc, xi, 1870, p. 295. 
Agomphus firmus. Cope, Proc. Amer. Philos. Soc, xii, 1871, p. 46; Vert. Cret. Form. West. 1875, p. 

262.— Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445.— Wieland, Amer. Jour. Sci. (4), 

XX, 1905, p. 4+3- 



DERMATEMYDID^. 



255 



The materials possest by Leidy when he described this species consisted of the third, 
sixth, and the seventh left peripherals, the sixth, seventh, and eighth peripherals of the right 
side, a portion of the left hyoplastron, and a portion of the right hypoplastron. These had 
been placed in Dr. Leidy's hands by Professor George H. Cook, of the New Jersey Geological 
Survey. They had been found in the uppermost Cretaceous greensand, at Tinton Falls, 
Monmouth County, New Jersey. The sixth and seventh left peripherals and the parts of the 
plastron were figured by Leidy, as cited above, and these are now in the State collection 
at Rutgers College, New Brunswick, New Jersey. The peripherals mentioned by Leidy are 
not in this collection at present. 

For figures of the scanty remains forming the type the reader is referred to Leidy's paper 
in the Smithsonian Contributions cited in the synonymy. 

The length of the figured peripherals is 140 mm. The height of the seventh is 93 mm. 
The costo-marginal sulcus crosses these peripherals between the upper and middle thirds. 
This shows that the species does not belong to Adocus. 

The left hyoplastron has a length of 80 mm., altho its length along the median suture is 
somewhat less. The hypoplastron had a length of 85 mm. but only 65 mm. at the midline. 
As shown by Leidy's figure, the hypoplastron articulated both in front and behind with the 
bones of the opposite side, a condition not unusual with the members of the family. The 
thickness of the hyoplastron at the midline and just behind the entoplastron is 26 mm. The 
greatest thickness of the hypoplastron is 19 mm. 

The excavation in the front of the hyoplastron shows that the entoplastron was truncated 
behind and that its width was about 65 mm. The pectoro-abdominal sulcus crost the hyo- 
plastron somewhat in front of the middle of its length; while the abdomino-femoral crost 
the hypoplastron about the middle of its length. 

This species, known up to the present time from only the type specimens, differs from all 
the other described species of Agomphus in having the entoplastron truncated behind and in 
having the pectoro-abdominal sulcus cross nearer the entoplastron than to the hinder border 
of the hyoplastron. 

Agomphus masculinus Wieland. 
Fig. 319. 

Agomphus masculinus , Wieland, Amer. Jour. Sci. (4), xx, 1905, p. 457, fig. 8. 

The type of this species belongs to the Marsh collection at Yale University Museum and is 
numbered 671. It consists of the complete plastron and some portions of the carapace, includ- 
ing some of the hinder peripherals. It was collected 
in the Upper Cretaceous marl bed at Barnesboro, 
Gloucester County, New Jersey, in 1872. 

The plastron (fig. 319) resembles closely that of 
A. turgidus, so far as the latter is represented. Dr. 
Wieland has mentioned one character which differ- 
entiates the carapace from that of Cope's species just 
mentioned. In A. masculinus the eleventh and 
twelfth marginal scutes overlap the lower ends of 
the eighth costal bone and the suprapygal; whereas 
in A. turgidus these marginals do not rise above 
the peripherals. This appears to be a sufficient 
specific distinction. 

The length of the plastron is 170 mm.; the 
extreme width, 130 mm. The anterior lobe narrows 
rapidly from the base to the blunt tip. The width 
of the base of the lobe is about 92 mm.; the length, 
41 mm. The epiplastrals are narrow. The ento- 
plastron is subrhombic, 33 mm. long and 36 mm. 
Fig. 2ig.— Agomphus masculinus. Plastron wide. Its thickness is 15 mm. The other plastral 
of type. xL Redrawn from Wieland's bones are unsymmetrical, as is common among the 
figure. older turtles. The left hyoplastron joins the right 




256 



FOSSIL TURTLES OF NORTH AMERICA. 



hypoplastron a distance of 14 mm.; while the right hypoplastron comes into contact with the 
left xiphiplastron. The greatest thickness of the hyoplastron and hypoplastron is 18 mm. 
The distance between the entoplastron and the xiphiplastron is 84 mm. Half of this may be 
regarded as belonging to the hyoplastrals; the other half to the hypoplastron. 

The bridge is 100 mm. wide. The hinder lobe is much reduced. The width at the base 
is about 68 mm.; its length, 48 mm. The greatest thickness of the xiphiplastra is 16 mm. 

The plastral scutes are well exhibited. Leaving out of count the inframarginals, there 
are 5 pairs of plastral scutes, instead of the 7 that we find in Adocus. One pair occupies the 
area covered in Adocus by the intergulars, the gulars, and the humerals. This pair joins along 
the midline a distance of 23 mm. The members of the pair differ somewhat in size and form. 
Behind this pair the median sulcus is erratic in its course. The pectorals measure 48 mm. 
along the midline; the abdominals, 31 mm.; the femorals, 38 mm.; the anals, 28 mm. Here, 
as in A. tardus, there appear to be only two inframarginals on each bridge, a small axillary 
scute and a very large scute behind this, reaching to the inguinal notch. Some of the marginal 
scutes descend on the outer ends of the plastral bones. 

As stated, the eleventh and twelfth marginal scutes rise above the superior borders of the 
peripherals supporting them. In front of them the marginals are confined to the peripherals. 

Agomphus oxysternum (Cope). 
Fig. 320. 

Amphitmys oxysternum, CoPE, Proc. Amer. Philos. Soc. XVII, 1877, p. 82; Palaeontolog. Bull. No. 25, 

1877, p. 2; Amer. Naturalist, xii, 1878, p. 129. 
Agomphus oxysternum. Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445. — Wieland, Amer. Jour. 

Sci. (4), XX, 1905, p. 443. 

The type of the present species is in the collection of the Geological Survey of Georgia, at 
Atlanta, where the writer has been permitted to study it. The specimen was found near Monte- 
zuma, Macon County, near the Flint River, in what is known 
as the Midway formation, a member of the Lower Eocene. It 
is in the same condition as when it was described by Professor 
Cope, the plastron being present, as well as the anterior portion 
of the carapace and the left border as far as the hinder end of the 
eighth peripheral. The core of matrix which filled the shell is in 
large part present and on it are indicated the sutures between the 
series of neural and costal bones. In form the shell appears to 
have been similar to that oi A. tardus. 

The length of the carapace, from the front of the nuchal to the 
hinder border of the seventh costal, is 242 mm. Cope gives this as 
250 mm. The width is 184 mm.; the height, 150 mm. or a little 
more. 

The free border in front of the bridge is thick, obtuse, and 
slightly flared upward. The hinder end of the eighth peripheral 
is 18 mm. thick, and the free border is very obtuse. The nuchal 
bone measures about 50 mm. along the free border, 75 mm. 
where widest, and 41 mm. from front to the rear. The neurals, 
except the first, are slightly wider than long. The dimensions of 
three of them are given in the table on the following page. 

The neurals and costals are thick. Cope states that the 
second neural is 13 mm. thick; the second costal, 12 mm. The 
latter bone near the neural is only 10 mm. thick. The first per- 
ipheral measures along the free border 38 mm.; the third, 40 
mm. The first is 33 mm. high; the second, 38 mm. 

The first vertebral scute is 53 mm. long and 52 mm. wide. 
Its lateral borders are nearly parallel. The second vertebral is 70 mm. wide. The marginal 
scutes, as far backward as the middle of the bridge, run about 40 mm. below the costo-periph- 
eral sutures. 




Fig. 320. — Agomphus oxyster- 
num. Carapace of type. 



Neural. 


Length . 


Width. 


I 
% 
5 


38 

3' 
3' 


27 
33 
32 



DERMATEMYDID.S:. 257 

The plastron has the extremities of the front and hinder lobes slightly elevated above the 
portion between the bridges. The length is 211 mm. The anterior lobe is broadly rounded in 
front; the posterior is short and pointed behind. The width of the anterior, on a line crossing 

at the hinder border of the entoplastron, is 102 mm.; its length 
is 57 mm. The entoplastron is pointed in front, rounded behind, 
42 mm. long and 46 mm. wide. The bridge has a width of 94 
mm. The hinder lobe has a width, taken from the ends of the 
abdomino-femoral sulci, of 88 mm. Its length is 57 mm. 

Some of the sulci of the plastron are very obscure. Cope 
was in doubt regarding some of those on the anterior lobe. One 
sulcus crosses the entoplastron 37 mm. behind the front of 
the lobe. Cope regarded this as the gulo-humeral; the writer regards it as the humero-pectoral. 
The area in front of this appears to the writer to be divided on each side into an intergular, 
whose extent backward is doubtful, a small triangular gular, and a large humeral. Cope 
appears to have been doubtful whether the sulcus behind the scutes, called by the present 
writer gulars, continued directly across the front lobe, cutting off intergulars in front, or 
turned backward and reacht the sulcus which crosses the entoplastron. 

Cope found evidences of a sulcus, his humero-pectoral, which commenct near the axillary 
notch, ran forward parallel with the free border of the lobe, then turned inward and somewhat 
backward, to cross the midline a little behind the entoplastron. The present writer, examining 
the plastron without knowing Cope's determinations, did not observe such a sulcus. It is 
not found on other species oS. Agomphus. 

According to the writer's determinations, the pectoral scutes join along the midline a 
distance of 58 mm.; the abdominals, a distance of 26 mm. The femoro-anal sulcus appears to 
be where drawn. Cope concluded that inframarginal scutes are present. The writer has no 
doubt regarding this. 

Dr. George Baur (Zool. Anzeiger, xi, 1888, p. 595) stated that he had examined the 
type of this species and regarded it as belonging to the genus Agomphus. He also informed us 
that additional materials existed in the Yale University collection, but nothing further has 
been heard of them. 

Genus ZYGORAMMA Cope. 

Characters, so far as known, those of Adocus, except that the hypoplastron sends no 
buttress to the costals, but each sends a process into a pit between the seventh and eighth 
peripherals. Bones of the carapace and plastron comparatively thin. Costals articulating 
with peripherals by suture and gomphosis. Rib-heads feebly developt, except on the first 
costals. Surface of carapace striated. Posterior marginal scutes rising on the costal bones 
as in Adocus. 

Type: Zygoramma striatula Cope. 

Zygoramma striatula Cope. 
Plate 37, fig. 10; plate 38, figs. 1-3; text-fig. 321. 

Zygoramma striatula. Cope, Proc. Atner. Philos. Soc, xi, 1870, p. 550; Ibid, xii, 1871, p. 44; Vert. 
Cret. Form. West, 1875, p. 263. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445. 

This species was based on rather fragmentary materials which were collected from the 
upper greensand bed of the Cretaceous, at Pemberton, Burlington County, New Jersey. 
The remains consist of the greater portion of both hypoplastra, 5 posterior peripherals, and 
fragments of 3 costal bones. This type is in the American Museum of Natural History and 
bears the catalog number 2358. 

The hypoplastrals (plate 38, fig. i) are thin, the thickness everywhere along the hyo- 
hypoplastral suture present being only 6 mm. Near the midline, just in front of the suture 
with the xiphiplastrals, the thickness is 7 mm., increasing to 9 mm. near the free border, 
behind the inguinal notch. 

The sutures are coarse, each bone sending large teeth into pits of the other. These pits 
and teeth belong to the deeper layers of the bone; while the sutures, as seen from below, 

17 



258 FOSSIL TURTLES OF NORTH AMERICA. 

form nearly smooth lines. The hypoplastra meet along the midline a distance of 80 mm. The 
one of the right side has articulated by its anterior angle with the left hyoplastron for a short 
distance. The free border of the left hypoplastron is present from the inguinal notch to 
xiphiplastral suture. Below, it presents an acute edge; but the bone thickens rapidly. Out- 
side of the notch a process is sent outward and upward to enter a pit between the seventh 
and eighth peripherals. The abdomino-femoral sulcus crosses the hypoplastra a little nearer 
the anterior end of these bones. The region where we might expect to find the inframarginal 
scutes is broken away. The longitudinal median sulcus is not seen. 

The sculpture of the plastron is obscure, but there are evidences everywhere of shallow pits, 
and these were arranged, at least partly, in rows. 

There are preserved the distal ends of 2 costals, one of which is the sixth of the right side, 
while the other belongs to the left side. The sixth of the right side (plate 38, fig. 2) is 38 mm. 
wide and 4 mm. thick. It is attacht principally to the eighth peripheral, but also to the anterior 
angle of the ninth. On the outer surface are seen parts of the third and fourth costal scutes, 
and of the eighth and ninth marginal scutes. The other distal end of a costal, probably the 
fifth of the left side, is 43 mm. wide and 4 mm. thick. A fragment of a costal from about the 
middle of the length of the bone is 35 mm. wide and 6 mm. thick. This seems to indicate 
that the costals thickened considerably toward the neurals. 

Three successive peripherals of the right side are among the materials, the seventh, 
eighth, and ninth (plate 38, fig. 2). They are remarkable for their great height. The seventh 
measures 46 mm. along the free border; the eighth and ninth, each 49 mm. The height of 
the latter is 65 mm. The exterior surface of the seventh is convex, with the free edge flared 
slightly upward. The other two are not curved vertically, but are convex from front to back. 
The greatest thickness of the ninth is at the front border, 1 1 mm. The thickness is reduced 
upward to the sutural border, less rapidly downward to the sharp free edge. The eighth 
thickens rapidly toward the anterior end, where, at the middle of the height, the thickness is 
23 mm. The thickening is exprest on the inner surface as a ridge. The hinder and lower 
inner portion of the seventh is likewise thickened, but the front and upper part is excavated 
by the visceral chamber. Above the thickened ridge, on the inside of each of these peripherals, 
is seen the mouth of a deep pit which received the free end of a rib. Two of these rib-ends 
are yet in place, one belonging to the sixth costal. 

Between the seventh and eighth peripherals, on their inner side (plate 38, fig. 3), there is 
a deep pit, excavated principally in the seventh, which has received the extremity of the 
inguinal process of the hypoplastron. The latter did not rise to the height of the costal plates. 
From the front of the pit a sharp ridge runs downward and forward. This has its inwardly 
projecting edge broken away, but it quite certainly furnisht an articulation with the outer 
border of the hypoplastron. The seventh peripheral of the left side is present, but furnishes 
no additional information. A more posterior peripheral, possibly the eleventh, has the exterior 
surface considerably more concave vertically than that of the more anterior ones, showing 

that the hinder border of the carapace was flared upward. Plate 
37, fig. ID, shows a fragment of a bridge peripheral with a portion 
of the end of a rib inserted in a furrow. Text-fig. 321 represents 
a section of a bridge peripheral showing that there was a sharp 
keel along the side. 

„ „ .As will be observed from the plate, the hinder marginal scutes 

riG. ^21. — Lyeoramma stria- , , , , , •-ri • 1 • 1 1 -j i_ 

, , c ^.- extended up on the costal plates. 1 he nmth margmal has a width 

tula. Section across a ire jL-i_ro t uj 

bridee peripheral. Xs. lore and att ot 52 mm., and a height of 85 mm. Its upper border 

displays some of the irregularities so common among the Der- 

matemydidae. On the costal supposed to be the fifth of the left side the sulcus between the 

marginal and the costal scutes runs lower down. 

The outer surface of the costals and peripherals is sculptured into low ridges and shallow 
grooves. These are mostly directed from the front of the bone backward, but often also 
slightly downward. The downward inclination is seen especially on the more posterior bones. 
The length of the carapace of this specimen is estimated at 380 mm. 




DERMATEMYDID^. 



259 



Zygoramma microglypha Cope. 
Fig. 321. 

Zygoramma microglypha. Cope, Proc. Amer. Philos. Soc, xii, 1871, p. 44; Vert.Cret. Form. West, 1875, 
p. 263. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 445. 

The remains described under the above name were found at Birmingham, New Jersey, 
in the uppermost stratum of Cretaceous greensand. They consisted of the greater part of the 
plastron and half of the carapace, with 4 peripheral bones, of an individual whose carapace 
must have had a length of about 600 mm. A portion of this material has been recognized in 
the Cope collection of reptiles, in the American Museum of Natural History, and this bears 
the number 6129. Unfortunately, up to the present time, no bones of the plastron have been 
found in the collection. No part of the species has hitherto been figured. 

The plastron is described as having a total length of 457 mm. According to Cope's 
measurements, the length of the hyoplastron was 81 mm.; that of the hypoplastron, 145 mm.; 
that of the xiphiplastron, 117 mm. The length of the hyoplastron was probably taken along 

the midline. The front of the plastron 
was truncated. The width of the 
entoplastron was 95 mm.; its length 
something less; its thickness 1 1. 6 mm. 
The posterior border was truncated; 
the anterior border, regularly convex. 
The posterior plastral lobe was regu- 
larly contracted, and rounded, and it 
had a thin edge. Its width at the 
hypoxiphiplastral suture was 220 
mm.; the thickness at the midline, 
15.8 mm. 

The peripheral bones at the 
bridges are said to have had a thick- 
ened shoulder within, into which the 
slender costal processes were received. 
The free peripherals were of lighter 
construction and somewhat everted. 
Most of the bones of the carapace 
that have been certainly identified are 
here figured (fig. 322). These consist 
of a portion of the first neural, the 
third and the fourth neurals, the prox- 
imal end of the first and third left cos- 
tals, parts or wholes of the second, 
third, fourth, and fifth right costals, 




Portion of carapace 



Fig. 322. — Zygoramma microglypha. 
of type. X\. 

c. p* If c. p. 3, c. p. 5, costal plates; n. i, n. 3, n. 4, neural bones. 

and portions of other costals whose positions can not be determined. 

The first neural has a length of about 57 mm.; its width is 45 mm.; its thickness, 8 mm. 
The third and the fourth have each a median length of 60 mm. and a maximum width of 
37 mm. Each is excavated in front for the preceding neural. Each has a thickness, where 
it joined the costal, of 10 mm. The first costal is 80 mm. wide; the second, 56 mm.; the third 
59 mm. ; the fourth, 55 mm. On the lower side of the first there is the base of a strong rib- 
head, and in front of this a rough articulation for the first rib. The rib-heads of the other 
costals are very feebly developt. 

The sulci between the horny scutes are moderately distinct. The second vertebral had 
a length close to 105 mm. and a width about equal to the length. The first vertebral must 
have been considerably wider than the second. The third vertebral appears to have had a 
length of 115 mm. and a width close to 95 mm. 

As in Z. striatiila, the marginal scutes extend high up on the distal ends of the costal bones, 
as may be seen from the figure. They pursue an irregular course. 



26o FOSSIL TURTLES OF NORTH AMERICA. 

According to Cope, the intergular scutes formed a single shield, which was large, pentag- 
onal, with straight sides, and broader than long. This shield separated widely the gulars 
from each other. The pectorals encroacht on the entoplastron; laterally they were narrow. 
The abdomino-femoral sulcus crost the hypoplastra a little behind their middle. The median 
longitudinal sulcus pursued an erratic course. 

This species evidently resembled closely Z. striatula. The distinguishing character most 
obvious is the finer and conspicuously punctate sculpture. Cope states that the costal pro- 
cesses that fit into the peripherals of Z. striatula are relatively twice as large as those of Z. 
microglypha. 

In its sculpture this species resembles the species of Adocus. 

Genus HOMOROPHUS Cope. 

A remarkable, but insufficiently known genus of Dermatemydidae. Costal rib-heads 
wanting or vestigial. Neurals, in the type and only known specimen, co-ossified with the cos- 
tals. The superior face of each neural much wider than the inferior face. Vertebral scutes in 
most places narrower than the neurals. 

Type: Homorophus tnsuetus Cope. 

Homorophus insuetus Cope 

Homorophus insuetus, CoPE, Proc. Amer. Philos. Soc, XI, 1870, p. 552; Ibid., XTI, 1871, p. 44; Vert. 
Cret. Form. West, 1875, p. 263. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 446. 

The type of this species appears to be lost. It was discovered in the uppermost bed of 
Cretaceous greensand, at Pemberton, Burlington County, New Jersey. Cope does not state 
what parts of the shell he had, but he describes some neural bones, the entoplastron, the 
hyoplastron, the hypoplastron, and some costals. He had neither the epiplastra nor the 
xiphiplastra. 

The hyoplastron and the hypoplastron together measured 200 mm. along the midline. 
On comparing these parts of the plastron with the same parts in Baptemys it is concluded that 
the plastron had a length of about 420 mm. 

The sutures bounding the neural bones appear to have been obscure. Cope says that one 
of the neurals was 14 mm. thick, 60 mm. long, 28.5 mm. wide in front, and 91 mm. wide 
behind. It is possible that there was here some error in observation or in statement. On the 
visceral face the neurals were very narrow, but they expanded, so that a transverse section 
resembled that of a broad wedge with truncated apex. The vertebral scutes had a remarkable 
form. For the most part, they were narrower than the neural bones. One is described as 
having the front coffin-shaped, the lateral margins concave, and the posterior end expanded, 
so that the scute was fiddle-shaped. The anterior vertebral is stated to have been 60 mm. 
long and 35 mm. wide anteriorly. The posterior costal scutes are described as meeting 
in the midline behind. 

The thickness of the hyoplastron was 15 mm. The free border of the hypoplastron was 
thinned to an edge. 

Genus ALAMOSEMYS nov. 

Differs from Adocus, so far as known, in having the marginal scutes wholly excluded from 
the costal bones. 

Type: Alamosemys subsinctaHzy. 

The generic name is derived from the name of the stream where the type was found. 

Alamosemys substricta sp. nov. 
Plate 39, figs. I, 2; teit-figs. 323, 324. 

The specimen which serves as the type of this species was collected in the Torrejon 
deposits of New Mexico, near the head of Alamosa Creek, in 1896, by Dr. J. L. Wortman 
and Mr. W. Granger. It bears the catalog number 1204, in the American Museum. 



DERMATEMYDIDj^. 



261 



The specimen is a complete shell, extremely little damage having been done to either the 
carapace or the plastron through loss of any part. Unfortunately, however, an extremely 
compact clayey limestone has envelopt the shell, and this clings so closely to the bone that it 
was very difficult to remove it. In addition to this, there had been deposited over considerable 
portions of the shell scattered nodular masses of hematite, which became so thoroly 
attacht to the bone that, in removing them, the surface of the bone was somewhat injured. 
This condition has resulted in making it very difficult to determine the position and courses 
of some of the sutures between the bones, and likewise the impressions between the different 
epidermal scutes. Many of the bone sutures could be determined only by removing, by 
means of hydrochloric acid, a thin layer of bone so that the matrix in the sutures projected 
a little. The obdurate nature of the matrix which fills the shell has seemed to render it 
inadvisable to attempt to remove it for the purpose of seeing characters found on the inside 
of the shell. 

The specimen has been carefully studied and the various sutures and sulci have been 
represented in the figures herewith provided. As to the bone sutures, they have been satis- 
factorily made out and may be relied upon. Many of the epidermal sulci have been more 
difficult to determine; but in general, it is believed that they are correctly mapt. 





324- 



Figs. 323 and 324. — Alamosemys substricta. Carapace and plastron of type. Xj. 
323. Carapace. 324. Plastron. 

The carapace (plate 39, fig. i ; text-fig. 323) is elongated, moderately elevated, decidedly 
constricted at the inguinal notches, and with the peripherals behind these somewhat flaring. 
A remarkable feature of the shell, shared by Adocus, is the large part of it which lies behind 
the sutures separating the third and fourth costal plates above and that which separates the 
hyoplastrals from the hypoplastrals. Sixty per cent, of the length lies behind the line indicated. 
So far as known to the writer, this is approacht only in Chelydra of living genera. Nearly 
half of the entire length lies behind the inguinal notches. 

In front, over the neck, there is an emargination in the border of the shell, while there are 
some feeble serrations in the hinder border. The extreme length of the carapace, in a straight 
line, is 550 mm. The greatest width, 380 mm., is just behind the inguinal notches; between 
the third and fourth costals the width is 372 mm. The greatest depth of the shell is 150 mm., 
but in life this may have been greater. On each side of the middle line of the carapace, for 
some distance, the shell is flat, there being no suggestion of a keel. The nuchal bone is 55 mm. 
long in the midline; its lateral extent is 53 mm. at the anterior margin; 90 mm. where widest. 
There are 7 neurals. The eighth was wholly supprest; the sixth and seventh were reduced in 
size and crowded forward. The first is broadly oval, 57 mm. long and 32 mm. wide. The 
second is narrowly oval, 44 mm. long and 18 mm. wide; the third, fourth, and fifth are hex- 



262 FOSSIL TURTLES OK NORTH AMERICA. 

agonal, with the broader end forward; the third being 56 mm. long and 25 mm. wide; the 
fourth, 46 mm. long and 22 mm. wide; the fifth, 38 mm. long and 22 mm. wide. The sixth is 
hexagonal, 20 mm. long and 28 mm. wide. The seventh neural is pentagonal, 22 mm. long and 
17 mm. wide. It has the appearance of having been crowded far forward out of its place. 
There is a single broad suprapygal whose length is 46 mm. and width 100 mm. 

The members of the sixth, seventh, and eighth pairs of costals respectively meet along 
the midline. The suture between those of the eighth pair is 82 mm. long. The peripherals 
are unusually high, about 100 mm. along the sides; somewhat less toward each extremity of 
the animal, the first and eleventh being about 64 mm. high. The free peripherals are thin at 
the borders, and the hinder ones are reduced to a sharp edge. The thickness of the second 
peripheral, near the upper border, is 20 mm.; that of the ninth, at the upper border, is 16 
mm. There are 1 1 of these peripherals on each side. 

As stated, it is difficult, in a few cases impossible, to determine satisfactorily the bound- 
aries of the epidermal scutes. In front there is a very narrow nuchal, about 10 mm. wide 
and 20 mm. long. This is followed by a first marginal, 58 mm. along the front edge and 
30 mm. fore and aft. The sulci between the marginals and the costal scutes appear to run at 
a considerable distance below the sutures between the costal and peripheral bones, the mar- 
ginals being about 75 mm. high. The limits of the vertebral scutes are satisfactorily deter- 
mined, except those of the fifth. The first vertebral is 80 mm. long and 130 mm. across its 
anterior end. The second is 100 mm. long and 65 mm. wide; the third 90 mm. long and 66 mm. 
wide; the fourth apparently 108 mm. long and close to 58 mm. wide. The fifth was probably 
1 15 mm. long and about 130 mm. wide. 

The surface of the carapace, including the lower faces of the peripherals, is ornamented 
with narrow and low longitudinal wrinkles of which there are from five to eight in a 10 mm. 
line. They are possibly due to the great age of the specimen and may be wanting in the 
younger individuals. 

The plastron (plate 39, fig. 2; text-fig. 324) is well developt, altho it leaves wide spaces 
between it and the carapace. It was apparently quite flat, altho now somewhat concave 
transversely, the result possibly of pressure. The total length is 415 mm. The anterior lobe 
projects nearly as far forward as the anterior border of the carapace; but the hinder fails to 
extend as far backward as the carapace by about 115 mm. The anterior end of the plastron 
is very slightly emarginated; the posterior end is broadly rounded and without notch. 

The length of the anterior lobe is 100 mm.; its width at the axillary notch 209 mm. It 
decreases in width gradually at first, then rounds rapidly to the notch in front. Its thickness 
near the front is 9 mm. The length of the posterior lobe is 132 mm.; its width at the inguinal 
notches is 190 mm. The bridge is 180 mm. in width. The axillary and inguinal buttresses 
do not appear to extend inward beyond the adjacent borders of the plastron. 

The entoplastral bone is short and broad and with a nearly straight hinder border. Its 
length is 55 mm; its width, 90 mm. The hyoplastral bones meet along the midline for a dis- 
tance of 100 mm. The suture separating the hypoplastrals from the xiphiplastrals is believed 
to be placed as shown in the figures. The former bones occupy 135 mm. of the midline; the 
latter, 84 mm. 

Gular and intergular scutes seem to be present and to have the positions and forms given 
them in the figures. The intergular area is evidently divided by a median sulcus. The two 
taken together are 75 mm. wide and 50 mm. long. The gulars are small, triangular, and 
widely separated by the intergulars. 

The humero-pectoral sulcus crosses the midline at the hinder end of the entoplastron. 
The humerals meet on the entoplastron for a distance of 48 mm. The pectorals extend 
along the midline only 46 mm. Altho the femoro-abdominal sulcus is not as distinct as 
might be desired, it is probably placed correctly in the figures. The abdominals thus have a 
fore-and-aft extent of 128 mm. The femorals extend along the midline 80 mm.; the anals, 
67 mm. 

On the bridges of the plastron there are at least four inframarginals. Of these, the one 
in front is small and square; the second, pentagonal; while the fifth is probably hexagonal. 
The third is 95 mm. long and 42 mm. wide, and may possibly be subdivided; but no sulcus 
is visible. 



DERMATEMYDID^. 263 

The surface of the bones of the plastron appears, for the most part, to have been smooth, 
but there are some indications of the same kind of wrinkling, or folding, as is seen on the upper 
surface. This is especially the case on the bridges and lower ends of the bridge peripherals. 

Genus HOPLOCHELYS nov. 

Shell thick and solid. Peripherals united to the plastral bones by means of digitations 
and dentated sutures; with the costals by gomphosis and in addition by simple apposition or 
sutures. Carapace furnisht above with three carinas. Plastron with anterior lobe immovable 
and with the posterior lobe narrow. 

Type: Chelydra crassa Cope. 

The characters of this genus are derived wholly from the shell. The plastral structures 
are not well known in any of the species. The genus appears to be related to Staurotypus 
now living in Central America. The latter possesses only 10 peripheral bones on each side. 
It appears not improbable that H. saliens and H. paludosa, having the peripherals sutured 
to the costals, really belong to a distinct genus. 

Hoplochelys crassa (Cope). 
Plate 38, figs. 4-9; text-fig. 325. 

Dermatemys sp., CoPE, Proc. Amer. Philos. Soc, XX, 1882, p. 461 (no description). 

Chelydra crassa, CoPE, Science (i), XI, 1888, p. 198 (no description); Trans. Amer. Philos. Soc, (2,) 

XVI, 1888, p. 306. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 446. 
Hoplochelys crassa. Hay, Amer. Geologist, xxxv, 1905, p. ^39. 

Professor Cope's first description of this species appeared in the Transactions of the 
American Philosophical Society as cited above; but he had previously mentioned it, as earl>- 
as the year 1882, as a species oi Dermatemys. In no place does this author state the exact 
locality or level at which the specimens were found by his collector, Mr. David Baldwin. 
However, Cope's label, which accompanies the type specimen, states that it was found June 
6, 1883; and Dr. W. D. Matthew has been able to show from the labels found with the mam- 
mals collected by Mr. Baldwin that at that time the collector was in the neighborhood of 
Chaco Canyon, San Juan County, New Mexico. Both the Puerco and the Torrejon are 
found in that region and it is therefore uncertain to which of these the fossil belongs. Two 
other species referred to the genus come from the Torrejon. Cope's first mention of the 
species in 1882 was doubtless based on other specimens, possibly the three neurals of which 
he speaks in his description. 

Cope states that he possest remains of 2 individuals. Of the first there were present 2 
vertebral bones, 9 peripherals, and 3 plastrals; of the second, 3 vertebrals. The bones of the 
first-mentioned individual are now in the American Museum of Natural History and bear the 
catalog number 6091; where the remains of the second specimen are is not at present known. 

Of the 9 peripherals in Professor Cope's possession 4 are represented by only as many 
fragments. No neurals are present, but there are 2 fragments of costal plates (plate 38, fig. 8), 
which are not mentioned by Cope; unless, indeed, they were mistaken for neurals. A study 
of the materials at hand has convinct the writer that Professor Cope was nearer the truth 
when he regarded this species as a Dermatemys. 

As stated, no neural bones are preserved. The presence of a median keel must rest on 
Cope's statement and on the probability that such a keel would accompany the lateral keels. 
The latter were sharply defined (plate 38, fig. 8) and ran longitudinally at a distance of about 
10 mm. from the median border of the costal scutes. Along this keel, on the hinder portion 
of the costal scute represented, the crest rises but little above the surface of the bone; but 
immediately behind the sulcus that separates this scute from the next one there is a sudden 
depression of the bone, so that the keel stands up very prominently. As it is followed back- 
ward its apparent height diminishes. Where the sulcus crosses the keel the sulcus bends 
forward, then again backward, thus forming a sort of loop. One of the costals present is 20 
mm. wide, the other is 18 mm. The thickness through the keel is 6 mm., but this rapidly 
diminishes to about 3 mm. distally. The width of the vertebral scutes can not be determined. 



264 FOSSIL TURTLES OF NORTH AMERICA. 

It appears probable that the back of this species resembled closely that of Staurotypus tripor- 
catus, as represented on plate XXB of Gray's Catalogue of Shield Reptiles. 

None of the peripheral bones at hand show that there was a dentated suture between them 
and the costals. Those which articulated with the plastron are thick and heavy. Of these 
there were probably 5 on each side. Plate 38, figs. 4, 5, represents one which is regarded as 
the sixth peripheral of the right side. It is slightly larger than the corresponding one of the 
leftside. The length is 22 mm.; the thickness of the hinder end, 17 mm.; that of the anterior 
end, 10 mm. The outer surface is strongly convex, and furnisht with a longitudinal sharp 
ridge. The anterior portion of the inner surface is concave. Along the lower border of this 
face are three excavations for digitations from the hypoplastron. Near the upper border is a 
deep cylindrical pit for the extremity of a rib. The hindermost digitation of the hypoplastron 
has evidently past on to the next peripheral behind, probably the seventh. Other thickened 
peripherals present almost certainly belonged farther forward and received the digitations of 
the hyoplastron. Between these and the thickened peripheral just described there was at 
least I, probably 2, thinner peripherals. One of these, the fourth or the fifth, is represented 
by figs. 6 and 7 of plate 38. Its length is 19 mm.; its height, 27 mm.; its greatest thickness 
9 mm. Its outer surface is convex perpendicularly, and is traverst by the continuation of the 
ridge described as occurring on the thickened peripherals. The inner surface is concave 
perpendicularly. In the upper half of this face is a pit for a rib-end; near the lower border 
are 3 shallow pits for digitations from the plastral bones. The lower edge was connected 

with the plastron by a dentate suture. 

r — T^ "^^^^ This bone or one similar to it was con- 

[ / hyo i( nected partly with the hyoplastron, 

ij;^^^;25i__l____ \ I partly with the hypoplastron. Each of 

"''y/^^^.:,.-"- ^ — — -^ these peripherals is traverst by a perpen- 

[ ". hypo p dicular sulcus. Along the upper border 

I? y" ^X^^ \^»,^ runs a longitudinal sulcus and along the 

( / \ li^~~y\ lower border another, all these forming 

\lv^ ^i^ll.!,' )) the boundaries of the marginal scutes. 

( // -^'g- 9 of ^^ plate cited represents 

^^"ccoi/ the pygal bone. Its length is 22 mm., its 

_ ^^ , , , „ ^ ■ , , , height 18 mm., its greatest thickness 8 

1*10. ^2^. — Jtloplochelys crassa. Part of right hvoplastron, „ d j- i 1 ^l r 

»u 1 r. u I . J ir ■ u 1 L ui nim- rerpendicularly the outer face IS 

the lett hypoplastron, and one left peripheral, probably f . ■' , , 

the seventh. X§. concave, the mner strongly convex. It 

is doubtful whether the upper border 
formed a jagged suture with the suprapygal. Another free peripheral, probably the tenth, 
resembles the pygal in general features. 

Text-fig. 325 represents the left hypoplastron attacht to the seventh peripheral. Near the 
hyohypoplastral suture and near the midline the thickness of the bone is 9 mm.; at the outer 
extremity the thickness is 4 mm. At the narrowest portion the width is 11 mm. The 
bone was united with the one on the opposite side by a coarse suture; similarly with the 
xiphiplastron. With the thicker peripherals it was articulated by means of digitations; 
with the intermediate and thinner ones, by both digitations and dentated sutures. A pro- 
cess of the xiphiplastron extended along the outer, hinder angle of the hypoplastron. 
On the lower surface, between the outer and the middle thirds of the bone there is seen 
a shallow sulcus, the inner boundary of an inframarginal scute. Another sulcus begins 
at the inguinal notch and runs forward and inward to the meeting of the transverse and 
longitudinal sutures. 

On the left side of the figure last cited is represented the outer two-thirds of the hyoplas- 
tron of the right side. At the narrowest part the bone was 16.5 mm. wide. The bridge was, 
therefore, at its narrowest portion, about 27 mm. wide. On the outer end of the bone are sulci 
bounding portions of 2 inframarginal scutes. No other sulcus is seen on this bone; and it is 
not probable that there was one beginning at the axillary notch and running backward and 
inward to meet the one from the inguinal notch, such as we find in Chelydra. The whole 
arrangement appears to be like that of Staurotypus salvinii, as represented by Dr. Boulenger 
in his Catalogue of Chelonians. 



DERMATEMYDID^. 



265 



The xiphiplastra were evidently small bones, but there is no remnant of them preserved. 

The width of the shell of this specimen was about 130 mm. An estimate based on the 
width of the two costal plates shows that the length was approximately 185 mm. The animal 
was therefore somewhat broader relatively than either Staurotypus salvinii or S. triporcatus. 

So far as known, this species differs from H. saliens in having the bones of the plastron 
less firmly sutured with the peripherals and in having the latter bones, at least those of the 
bridge region, without close suture with the costals. The bridge is much narrower. 

Hoplochelys saliens sp. nov. 
Text-figs. 3x6, 327. 

The only specimen of this species at present known was found by Dr. J. L. Wortman 
in 1896, at the head of the Escavada Canyon, Rio Arriba County, New Mexico, in Torrejon 
deposits. It belongs to the American Museum of Natural History and bears the number 



326. 





Figs. 326 AND 327. — Hoplochelys saliens. Carapace and plastron of type. Xj. Restored 

portions in interrupted lines. 

326. Carapace. 327. Plastron and part of carapace. 

1200. The shell, the only portion preserved, is considerably crusht, but is nearly all present. 
The only parts missing are portions of the seventh and eighth costals, the hindermost neurals, 
and some portions of the plastron. Unfortunately for an understanding of the structure of 
the shell much of it was covered by a very refractory matrix, which adhered so closely that it 
had to be ground away to the bone. As a result, it is difficult to determine in many places 
the position of the boundaries of the scutes and sometimes of the sutures. Most of the periph- 
erals, however, have been beautifully weathered out and preserved. 

In form the carapace (fig. 326) was oval, rounded in front and behind, and apparently of 
some considerable elevation. The total length was close to 325 mm.; the width, close to 200 
mm. There was a median keel of moderate height. On each side of this, at a distance of 50 



266 FOSSIL TURTLES OF NORTH AMERICA. 

mm. in front, 30 mm. behind, there was a more prominent lateral keel. Along none of these 
keels was the bone suddenly sunken just behind the transverse sulci, as it is in H. crassa. 
In addition to these keels, there is on each side, on the bridge peripherals, a narrow ridge 
which passes in front and behind into the free edges of the peripherals. 

The rim of the carapace was formed by a nuchal, probably ten pairs of peripherals, and 
a pygal. The nuchal is excavated in front for the neck. The width in front is 43 mm,; its 
thickness is 11 mm.; its length can not be determined. The first peripheral is 32 mm. long 
on the free border and 38 mm. high. The second peripheral is 35 mm. long, concave above, 
convex below, and with an acute border. Farther backward this border runs into the rather 
sharp keel running along near the upper border of the bridge peripherals. The upper border 
of the bridge peripherals is plane, continuous with the surface of the costals, and 10 mm. 
or less wide. At the bottom of this surface just above the keel before mentioned run the 
sulci separating the costal scutes from the marginals. Immediately below the lateral 
keel the peripherals thicken suddenly and form a sort of roll along the shell. The form of 
this roll may be seen from the section of the peripheral of the next species, H. paludosa. 
The peripherals behind the bridge are slightly flared upward and are acute-edged. The 
width and length of the pygal can not be determined. The hinder border of the carapace 
was not notcht. 

The anterior costal plate had a width of about 50 mm.; the next 3 or 4 pairs, a width of 
35 mm. or a little more. The costals opposite the bridges have a thickness of 7 mm. at their 
distal ends. 

The neurals are broad, and with the broader end forward. The second has a width of 
about 35 mm.; the third about the same width; the fourth a width of 25 mm. The boundaries 
of those behind these can not be determined. The second vertebral scute has a width of 
about 75 mm.; the succeeding ones are narrower. 

The anterior lobe of the plastron (fig. 327) is about 100 mm. wide at the base. It appears 
probable that the epiplastrals are missing. The entoplastron appears to have the form 
and size represented in the figures. The epiplastra were probably in contact with the outer 
border of the hyoplastra as in Staurotypus salvinii (Boulenger's Catalogue, p. 31). The bridge 
has a width of about 60 mm., a little more than half of which is furnisht by the hyoplastron. 

The hinder lobe of the plastron is about 70 mm. wide at the base. The suture between 
the hypoplastra and the xiphiplastra was probably where shown in the figures, but this is not 
certain. The xiphiplastra probably came to a point posteriorly. 

Of Staurotypus salvinii, Sumichrast says (Bull. Soc. Zool. France, 1880, p. 169) that it 
lives in muddy pools. Its food consists of small aquatic animals, especially of mollusks 
belonging to the genus Atnpullaria. Its disposition is voracious and irritable. Its gait on 
land is free, and it runs with some swiftness, a fact due to the form of the plastron, which 
leaves to the limbs freedom of motion. 

The small posterior lobe of the plastron of Hoplochelys indicates that the hinder limbs 
were strong and endowed with freedom of movement. Its habits and disposition may have 
been not greatly different from those of Staurotypus. 

Hoplochelys paludosa sp. nov. 
Fig. 328. 

This species is based on a single peripheral bone, probably the seventh of the left side. 
It was found by Mr. Barnum Brown, in 1904, in Escavada Canyon, New Mexico, where H. 
saliens was discovered. It belongs to the American Museum of Natural History and has the 
number 6079. It differs from the latter species in lacking the longitudinal ridge along the 
convexity of the outer surface of the peripherals, and in having the suture with the costals 
much higher above the costo-marginal sulci. In the present species this suture is at a distance 
of 20 mm. above the sulcus, while in H. saliens it is only 10 mm. or less. The absence of the 
peripheral carina is regarded as an important specific character. The size of the individual 
has been probably slightly less than that of H. saliens, the length of the seventh peripheral 
of the latter being 35 mm.; of H. paludosa, 32 mm. 



dermatemydida:. 



267 



From H. crassa the present species differs in having the supposed seventh peripheral 
strongly sutured to the contiguous costal bone, in having no lateral carina, and in having the 

longitudinal sulcus at the middle of the 
height, instead of near the costal border. 

In the inner face of the bone are excava- 
tions for the reception of digitations from the 
plastron. One of these digitations remains in 
position, and shows that it extended backward 
ashortdistanceintotheeighth peripheral. The 
border which articulated with the costals is 7 
mm. thick. In the sutural edge is a deep pit, 10 
mm. in diameter, which received the extremity 
of the rib of the contiguous costal plate. 

Fig. 328 shows the type peripheral as 
seen from the outside. The drawing on the 
right presents a view of the hinder end of the bone; the one on the left, the anterior end. 




Fig. 328. — Hoplochelys paludosa. Supposed left 
seventh peripheral forming type. X§. A.M.N.H. 

a, bone seen from side; h, anterior end; c, posterior end; d, an 
adhering fragment of the plastron. 



Genus KALLISTIRA nov. 

Carapace thick and solid; provided with a median and two lateral carinas. Plastron 
unknown, except that its inguinal buttresses were extensively developt and ascended a con- 
siderable distance against the inner surface of the fifth and sixth costals. 

Type : Dermatemys costilatus Cope. 

Kallistira costilata (Cope). 

Figs. 329-334. 

Dermatemys? costilatus, CoPE, Syst. Catalogue Vert. Eocene, N. Max., 1875, p. 36. 

Dermatemys costilatus, CoPE, Report on Geol. N. Mex., 1874 (1875), p. 96; Wheeler's Surv. 100 Merid., 

IV, pt. ii, p. 52, plate xxiv, figs. 17-31. 
Baptemys costilatus. Hay, Bibliog. and Cat. P"oss. Vert. N. A., 1902, p. 445. 

The types of the present species belong to the U. S. National Museum and bear the number 
II 52. Not all the fragments that Cope figured are present. Those missing are the originals 
of Cope's figs. 17, 20, 23, 24, 26, and 31. Cope states that he had fragments representing 6 
individuals, and that parts ot 4 were figured. There appears to be no reason for doubting 
that all of these individuals belonged to the same species. Figures of some portions of these 
types are here presented. The species was found in the Wasatch beds of New Mexico. 

The species is characterized by its thick and heavy shell and the presence of at least 3 
carinae on the carapace, one running along the midline and one on each side of it. 

The fragment which furnisht Professor Cope's figs. 27 and 28 belongs to the upper end of 
a costal, probably either the second or the fourth. Cope's fig. 27 (fig. 329) is inverted on 
his plate. The width of the costal is 20 mm. It is crost by a low keel whose breadth is almost 
9 mm., but whose elevation is scarcely a millimeter; the thickness of the costal above the carina 
being 6 mm., that thru the carina, 7 mm. At the distal end of the fragment the thickness 
is 5 mm. This piece of costal presents a part of the sulcus bounding a vertebral scute laterally 
and the sulcus running down the costal. .These are extremely narrow and shallow. The 
longitudinal sulcus is at a maximum distance of 10 mm. from the proximal border of the costal 
and above the lateral carina. The vertebral scutes appear to have had a width of about 
42 mm. The proximal end of the costal is rounded, showing that the lateral borders of the 
adjacent neural were concave. Another costal, the one furnishing Cope's figs. 19 and 19a, 
belonged to a smaller individual. The carina is still less conspicuous than in the case of the 
one just described. The original of Cope's fig. 21 (fig. 330) has the carina more sharply 
defined and with a width of 5 mm. It is probable that, as suspected by Cope, the carinae 
were developt on the rear of the animal and disappeared anteriorly. 

Fig. 331 represents the original from which Cope obtained his fig. 30. It is a portion of the 
distal half of a costal, in all probability the fifth of the right side. The extreme end of the bone 



268 



FOSSIL TURTLES OF NORTH AMERICA. 



appears to be missing. The figure presents the inner, or visceral, surface. This bone is 4 mm. 
thick at its anterior border, but toward the other border it thickens greatly, so that a little 
beyond the middle of the width the thickness is 10 mm. From the line of its greatest thickness 
the bone is beveled off on the inner side to its hinder border, and against this beveled surface 
the sixth costal has articulated. A strongly developt buttress from the plastron ascended 
against the inner surfaces of these two costals at their junction. The scar for this buttress on 
the fifth costal here figured is 20 mm. long. The plastron was therefore articulated with the 






331- 33°- 329- 

Figs. 329-331- — KalUstira costilata. Costals of the type. Xl. 

329. Proximal end of costal, second or fourth. 

330. Proximal end of costal, showing a carina. 

331. Distal end of costal, probably the fifth, showing scar 

for inguinal buttress of plastron. 

carapace in a very different way from that seen in other dermatemyds; and a distinct genus 
is indicated. 

Portions of 3 neurals are at hand, those represented by Cope's figs. 18, 22, and 25. The 
first-mentioned (fig. 332) has a width of 22 mm., probably belonged well forward, and was 
possibly the second. The median carina is barely perceptible. No sulcus crosses the portion 
present. That part of a neural from which Cope's fig. 25 was drawn (fig. 332^) is narrow and 
devoid of a carina. It is crost near the fracture by a narrow and shallow sulcus. It appears quite 
probable that this is the posterior end of the first neural. At its lateral border it is 5 mm. thick. 

The neural represented by Cope's fig. 22 (fig. 333) apparently belonged to the rear of the 
carapace, and resembles closely the sixth of Staurotypus salvinii. Its length is 18 mm.; 







332- 332a. 333. 334. 334a- 

Figs. 332-334. — KalUstira costilata. Neurals and a peripheral of type. Xi. 

332. 332(3. Portions of two neurals of the type. 332 is Cope's fig. 18; 

332a Cope's fig. 25. 

333. A hinder neural, showing carina. Cope's fig. 22. 

334. A hinder peripheral with a section {a) across it. 

greatest breadth about 20 mm.; thickness at the lateral border 4.5 mm., through the carina 
0.5 mm. The carina is sharply defined and wider in front than behind. 

A portion of a hinder peripheral is present, being the original of Cope's figs. 29 and 29a, 
and constituting, according to Cope, a portion of the same individual as those furnishing his 
figs. 27 and 30. Cope's figure is inverted. This (fig. 334) bone has a height of 27 mm. in a 
direct line, and a maximum thickness of 7 mm. Its width can not be determined, as the bone 
has been broken near the descending sulcus. This sulcus, in contradistinction to those of the 
costals and neurals, is broad and deeply and irregularly imprest. Along the upper border of 
the bone runs what appears to be the longitudinal, or costo-marginal, sulcus. On the under 



DERMATEMYDID^. 269 

side of the bone the descending sulcus is narrow and shallow, like those of the costals. This 
bone is strongly concave on the upper surface and has an acute free border. It was very 
loosely articulated with the contiguous costal; and in the upper border there is a pit for the 
extremity of the costal rib. Fig. 334a is a section of this bone. 

Professor Cope thought that this species attained about the size of Baptemys luyoming- 
ensis, but none of the bones described by him indicates a size so great. From the width of the 
costal represented by fig. 331 the writer estimates the length of the carapace at something less 
than 200 mm. 

Genus NOTOMORPHA Cope. 

A little-known genus. Anterior, and probably posterior, peripherals with obtuse free 
borders. Apparently intergulars large; the gulars small and removed far from the midline. 
Type: Notomorpha gravis Cope. 

The materials on which the genus Notomorpha was based are in the U. S. National 
Museum. In the original description of the genus (Proc. Amer. Philos. Soc, xii, 1872, p. 474) 
characters were attributed to it which were derived from bones of the species called in the 
present work Echmatemys testudinea. These bones, altho portions of the first costals with 
articular scars for axillary buttresses, were supposed by Cope to be xiphiplastrals with scars 
for the pubis. On the strength of these, the genus was assigned to the Pleurodira. Cope's 
discovery of his error regarding the character of the plastron, his removal of his species testu- 
dinea to Ernys, and his reduction of the species A^. garmanii to a synonym o{ N. gravis, left 
the latter the type of the genus. This he concluded was also a member of the Emydidae, but 
associated with Dermatemys and Agomphus. As the dermatemyd turtles are now regarded as 
a distinct family, Notomorpha must be arranged in that family. 

As stated above. Cope made his N . garmanii a synonym of N . gravis, a proper course in 
case there is only a single species involved; but of this there may be permitted grave doubts. 
Of his gravis he described a hyoplastron and an epiplastral of one individual and a costal of 
what was doubtfully another. The costal had a width of 58 mm., which indicated a very large 
turtle. Cope at first recognized important differences between the epiplastrals; but later he 
considered these of less importance. We may, then, have doubts regarding the specific iden- 
tity of the two lots of bones. Besides this, the materials figured all belong to his A'^. garmanii. 

Notwithstanding all this, until future discoveries shall have thrown additional light on 
Notomorpha, it will be best to place the few known remains under the specific name gravis. 

Notomorpha gravis Cope. 

F'gs- 335. 336- 

Notomorpha gravis, CoPE, Proc. Amer. Philos. Soc, Xll, 1872, p. 476. 
Notomorpha garmanii. Cope, Proc. Amer. Philos. Soc, xil, 1872, p. 477. 
Emys gravis, CoPE, Sixth Ann. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 626. 
Notomorpha gravis, CoPE, Vert. Tert. Form. West, 1884, p. 143, plate xxiii, figs. 14-16. — Hay, Bibliog. 
and Cat. Foss. Vert. N. A., 1902, p. 448. 

The bones on which Notomorpha gravis was based appear to have been lost. Those 
which Cope described as N. garmanii are now in the U. S. National Museum, some of these 
bearing the number 4103; others, belonging apparently to the same individual, have the 
number 4129. It is not known whether all the bones accompanying the figured specimens 
belonged to the same individuals or even the same species. We shall have to regard as types 
the remains which were figured by Cope. All three of these are numbered 4103. The bones 
originally described under the two specific names had been discovered in the Wasatch beds 
at a point near Bear River, 6 miles north of Evanston, Wyoming. 

The bone which was regarded as characteristic o( Notomorpha is the supposed epiplastron, 
the subject of Cope's fig. 14, plate xxiii, of his work on The Vertebrata of the Tertiary For- 
mations of the West. The writer has been unable to convince himself that this is the epi- 
plastron, altho it may be such. It may be a first peripheral. The upper border of the original 
of Cope's fig. 14, which was supposed to be the front of the lip, has the appearance of having 



270 



FOSSIL TURTLES OF NORTH AMERICA. 



been a sutural edge for articulation with another bone. The border between the supposed 
gular scutes is broken off. If the bone is an epiplastron it must once have projected con- 
siderably at this point, and the front of the anterior lobe was deeply emarginated. The length 
of the bone is about 40 mm.; its thickness behind is 1 1 mm. In case the bone is an epiplastron, 
the lip was about 40 mm. wide. The free border of the bone, that represented by the right 
side of the figure, is thick and obtuse. That of the same bone in Cope's type of AT. gravis, as 
originally described, was acute. In his last description of these bones this difference appears 
to have been thought of no specific importance. On the supposed under side of the bone are 
seen distinct sulci, indicating the supposed intergulars and the small triangular gulars. If 
such they are, affinity with the Dermatemydidae is indicated. Whether or not the intergular 
was divided at the midline we can not determine. 

Fig. 335 represents the third left peripheral (No. 4129, U. S. N. M.) seen from above, 
while fig. 336 presents a view of the sutural end which joins the second peripheral. It is seen 

that the free border is obtuse. The costo-marginal 
sulci ran along not far below the upper margin of the 
bone. The bone is 39 mm. high, 36 mm. along the 
free border, and 18 mm. thick. Cope figures 2 periph- 
erals, but the free borders were missing in both. 

Cope's fig. 15 is said to represent the posterior 
edge of the eighth peripheral of the right side; but it 
belonged to the left side. This bone was somewhat 
recurved; its height is about 44 mm.; its length on 
the free border 35 mm.; its thickness about 9 mm. at 
the border represented. The articular border for 
union with the costals was thin. 

The seventh peripheral (Cope's fig. 16) is stated 
to have been 42 mm. wide, 45 mm. high, and 15 mm. 
thick. This peripheral, the seventh of the left side, 
entered into the inguinal notch. Its free border was acute; its upper articular border was thin. 
Besides these peripherals, Cope had others belonging to the bridge region. These he states 
had very obtuse free borders. The general massiveness of these was in contrast with the thin- 
ness of the costals. The surface of the peripherals is said to have been obsoletely rugose. 
A vertebral bone is stated to have been 7 mm. thick. 





Figs. 335 and 336. — Notomorpha gravis. 
View of third left peripheral of the 
type, with section. X§. 

335. Peripheral seen from without. 

336. Section at anterior end. 



Genus BAPTEMYS Leidy. 

Plastron united with the carapace by means of sutures and by axillary and inguinal 
buttresses, which rise to the lower borders of the costals or beyond. Plastral lobes short and 
narrow, the hinder not notcht. Nuchal bone with short costiform processes. A full set of 
neurals. Marginal scutes not encroaching on the costal bones. Intergulars, gulars, and 
humerals of each side usually consolidated into one scute. Inframarginals present. 

Type: Baptemys wyomingensis Leidy. 

This is the only genus of the Dermatemydidae which possesses a full series of neurals. 
The pectoral scutes appear to have extended themselves forward to the epiplastrals and even 
further. The region which in Adocus is occupied by the intergulars, gulars, and humerals of 
each side presents usually only a single scute; but in a specimen of B. tricarinata (fig. 348) the 
gulo-humeral sulcus is partly developt. 

This genus is represented by 3 known species. Of these, one, B. fluviatilis, comes from 
uncertain locality and level. Of the others, B. tricarinata belongs to the Wind River beds, 
while B. tuyomingensis is common in the Bridget beds of southwestern Wyoming. 

Baptemys wyomingensis Leidy. 
Plate 37, figs. II-13; plate 38, fig. 10; plate 40, fig. 1; plate 41, figs, i, 2; text-figs. 337-345- 

Baptemys wyomingensis, Leidy, Proc. Acad. Nat. Sci. Phiia. 1870, p. 5; Ann. Report U. S. Gaol. Surv. 
Wyoming, etc., 1870 (1871), p. 367; Ann. Report U. S. Geol. Surv. Montana, etc., 1872, p. 367; 
Contrib. Ext. Fauna West Terrs., 1873, pp. 157, 340, plate xii, plate xv, fig. 6. — Cope, Ext. 



DERMATEMYDIDil. 



271 



Batrach. Reptilia, Aves N. A., 1869 (1870), p. ii. — Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, 

p. 445; Amer. Jour. Sci. (4), xvin, 1904, p. 265, plate xiii, figs. 1-3, text-fig. 2; Amer. Geologist, 

XXXV, 1905, p. 331. 
Adocus vyomingensis, CoPE, Ext. Batrach., Reptilia, Aves N. A., 1870, p. 233; Proc. Amer. Philos. See, 

XI, 1870, p. 297. 
Dermatemys wyomingensis. Cope, 6th Ann. Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 624; Amer. 

Naturalist, xvi, 1882, p. 991, fig. 9. 
Dermatemys vyomingensis, CoPE, Vert. Tert. I'orm. West, 1884, p. 142. 
Ba'ena ponJerosa, Cope, 6th Ann. Report U. S. Geol. Surv. Terrs, 1872 (1873), p. 624. 
Ba'ena? ponderosa, Hay, Bibliog. and Cat. Foss. Vert. N. A., 1903, p. 438. 

The type of the present species belongs to the Academy of Natural Sciences at Phila- 
delphia. The specimen was obtained somewhere in the neighborhood of Fort Bridger, 
Wyoming, from which locality probably all the known specimens have been derived. The 
level is therefore that of the lower portions of the Bridger beds. Of the type, some of the 
peripherals are missing, also the front of the plastron. The total length of the carapace in 
life was nearly 450 mm.; the breadth, about 310 mm. On the hinder third of the carapace 
there is a prominent carina, the summit of which is flat. The anterior neurals are considerably 
longer than wide, with the broader end directed forward. The free borders of the anterior 
peripherals are thickened and obtuse. The surface of the carapace is mostly smooth, but pos- 
teriorly somewhat corrugated. The dimensions of the vertebral scutes are given in the table. 

The plastron is relatively small, and 



Vertebrals of | 


Neurals of 1494 


Vertebrals of 


type. 


A.MJI.H. 


1494A.M.N.H. 


No. 


Length. 


i 
Width. 


No. Length. 


Width. 


No. Length. Width. 


I 


81 


108 




5° 


22 


I 68 90 


2 


104 


62 




4» 


22 


2 85 53 


3 


90 


68 


1 


45 


21 


3 83 55 


4 


79 


66 




40 


22 


4 86 60 


s 








4» 
37 
»5 


23 
28 
28 


5 no 104 

1 1 










'7-5 


27 


1 ! ! 



large spaces are left between it and the 
carapace, thus favoring the movements 
of the legs. The anterior lobe is 148 
mm. wide at the base. The bridge has a 
width of 105 mm. The hinder lobe ter- 
minates obtusely behind. The length is 
94 mm.; the width at the base, 115 mm. 
On each of the bridges are 3 inframar- 
ginal scutes. Of these the hindermost 
extends forward on the hyoplastron. 

Dr. Leidy described a second spec- 
imen which had been discovered at 
Church Buttes. This shell was impor- 
tant because it furnisht the front of the plastron, which Leidy figured in his Contributions 
(plate XV, fig. 6). This front, however, differs so much from that of all others found since, 
that there is some reason for suspecting that it belongs to a distinct species, being truncated 
and notcht in front. Below some details are given regarding this specimen. 

In the Cope collection belonging to the American Museum of Natural History is a large 
specimen which presents the carapace (plate 40, fig. I ; text-fig. 337); but of the plastron there 
is only the impression of the hinder lobe on the matrix. The catalog number is 1494. Were 
it not that Cope describes the form of the anterior lobe, it might be supposed that it is the 
specimen mentioned by him in the Proceedings of the American Philosophical Society (vol. 
XI, p. 297). It is possible that that author did not intend to state that his specimen possest 
this lobe, but referred to what Dr. Leidy had determined. The total length of the carapace is 
435 mm., in a straight line; the width is 283 mm.; and the height, about 180 mm. The 
specimen is remarkable for its narrowness. The anterior edge is thickened and rounded like 
the edge of one's little finger. The thickness of the first peripheral is 16 mm. The hinder 
free borders are also obtuse, but much thinner, the thickness near the edge of the tenth being 
7 mm.; but this increases to 14 mm. at half the height of the bone. The neurals are narrow. 
The dimensions of the neurals and the vertebral scutes are presented in the table above. 

There are 12 pairs of marginal scutes. The costo-marginal sulcus runs considerably below 
the costo-peripheral suture. There appears to be present a ninth pair of costal plates (fig. 337, 
f./>.?9). 

The American Museum expedition of 1903 secured 2 specimens of this species at Grizzly 
Buttes. These have the catalog numbers 5934 and 5967. No. 5967 presents a large portion 



y 



^1^ 



FOSSIL TURTLES OF NORTH AMERICA. 



of the skull. The shell of both specimens is quite complete. In neither is the front of the 
plastron truncated. The length of the carapace of No. 5967 (plate 41, figs. I, 2) was originally 
close to 430 mm.; its width about 330 mm.; but the shell has been strongly crusht down- 
ward. The first vertebral scute has a width anteriorly of 80 mm.; the next three, each a width 
of about 56 mm.; the fifth, a width of 128 mm. posteriorly. It will be observed that the last 
of these vertebrals is considerably wider than in the Cope specimen. On the hinder half of 
the carapace there is seen, on each side of the vertebral scutes, an indistinct flattened carina. 
These correspond to the much more prominent lateral keels seen in the predecessor of this 
species, B. tricarinata. 

The anterior lobe of the plastron is 100 mm. long and 152 mm. wide at the base. The 
lateral borders converge in nearly straight lines to opposite the front of the entoplastron; 
then they round rapidly to the midline. The entoplastron is large, 62 mm. long and 67 mm. 
wide. The bridge is 117 mm. wide. The hinder lobe is 92 mm. long and 130 mm. wide at 





Figs. 337 and 338. — Baptemys wyomingensis. Carapace and plastron. 

337. Carapace. Xi. No. 1494 A.M.N. H. c. /i. 9, probable ninth pair of costal bones. 

338. Plastron and border of carapace. X/s- Specimen in Yale University. 

the base. As in other known specimens, the intergulars, gulars, and humerals appear to have 
coalesct. The humero-pectoral sulcus crosses the entoplastron a little behind its middle, and 
on the hyoplastron it turns abruptly forward and outward. The anal scutes measure 51 mm. 
on the midline. Each of the other pairs measure about 62 mm. On each bridge there are 3 
inframarginals, as in the type of the species. The hindermost one is 1 10 mm. long on its 
outer border. 

The specimen numbered 5934 differs from the one just described in having the first 
vertebral scute unusually wide, 125 mm. The lateral borders of the anterior lobe of the 
plastron are not so straight as in No. 5967 and the extremity is slightly more pointed. The 
inframarginals are as in the latter. This specimen shows well the buttresses. The axillary 



DERMATEMYDID^. 2/3 

bones ascend to the borders of the first costals. The inguinal buttresses do not reach the 
upper borders of the peripherals. 

At Yale University is a specimen (No. 484) which was collected in 1870, at Millersville, 
Wyoming, therefore in the lower third of the Bridger deposits. It furnishes a crusht carapace 
and a complete plastron ftext-fig. 338), the nearly complete skull fplate 37, figs. 11, 12, 13), 
and portions of limb bones. The carapace has a length of 445 mm. and a width of 330 mm. 
There is a large suprapygal 45 mm. long and 70 mm. wide. The first vertebral scute is 100 
mm. wide; the second, 52 mm.; the third, 50 mm.; the fourth, 66 mm.; the fifth, 95 mm. 
Besides these normal vertebrals there is a small supernumerary one, 37 mm. long, cut off from 
the front of the normal fifth. The plastron (fig. 338) is 305 mm. long. As will be seen from 
the figure, there are on each bridge 4 inframarginals. A small one appears to have been cut 
off from the anterior end of the large third one of other specimens. In this specimen the 
anterior extremity of the plastron comes forward as far as the front of the carapace; but this 
is doubtless due to crushing. 

A specimen at Princeton University, No. 10074, is half as high as long. 

Dr. Leidy's second specimen, the one which furnisht the truncated anterior lobe of the 
plastron, is in the U. S. National Museum and has the number 5000. In all respects, except 
the form of this lobe, the specimen agrees with typical specimens of B. luyomingensts. The 
plastron alone is represented and of this a portion of the hinder lobe is missing. The length 
of the anterior lobe is 93 mm.; its width at the base 145 mm.; width at the epiplastral sutures, 
114 mm. The entoplastron is 76 mm. long and 64 mm. wide. The width of the bridge is 108 
mm. The hinder lobe has a width of 108 mm., diminishing in a curve to a width of 96 mm. 
at the hypoxiphiplastral sutures. 

Materials for the study of the skull are furnisht by the specimen at Yale University, 
bearing the number 484 (plate 37, figs. 11, 12, 13), and by number 5967 of the American 
Museum of Natural History (plate 38, fig. 10). Each of these skulls is accompanied by its 
shell. There appear to be no specific differences between them. The Yale skull is nearly 
complete, the only portions missing being the roof of the orbits and of the nasal cavities. 
The American Museum specimen supplies the parts missing in the Yale skull; but it is 
defective in many respects. That at Yale furnishes the description here given, unless other- 
wise specified. 

Relatively to the size of the shell the skull is small. It is broad behind and tapers forward 
to a rather narrow snout. The length, from the snout to the occipital condyle, is 67 mm.; to 
the extremity of the supraoccipital spine, 88 mm. The greatest width, taken at the upper 
borders of the tympanic cavities, is 58 mm. The temporal region is not rooft over, and there 
is no parieto-squamosal arch. The postorbital arch is slightly more than 7 mm. wide. The 
zygomatic bar is deeply excavated on its lower border, and is 10 mm. wide. At the hinder 
border of the orbit, where the maxilla joins the jugal, the former bone is only 5 mm. wide. 
The interorbital space, as shown by the American Museum specimen, has a width of 23 mm. 
The orbits are placed well forward. The antero-posterior diameter of each was about 20 mm.; 
the perpendicular, 17 mm., the latter dimension being furnisht by the American Museum 
specimen. This individual also shows that the nares had a perpendicular diameter of 1 1 mm., 
a transverse diameter of 16 mm. The upper jaw is convex on its lower border, rising in front 
so as to form a median notch. This upper jaw, as shown especially by the American Museum 
specimen, has a sharp cutting-edge, but no masticatory surface. This appears to be an indi- 
cation that this animal was not accustomed to crush shells, or other hard substances, but to 
live on more active prey. 

The tympanic cavity has the longest diameter directed upward and slightly backward; 
its outer rim is thick and heavy. The posterior wall is open, forming a notch for the passage 
of the stapedial rod. The sutures between the bones of the skull are close and some are to be 
traced only with difficulty. There seem to have been no nasals. As shown in the skull 
belonging to the American Museum, the prefrontals run backward over the orbits and join 
the postfrontals, excluding the frontals from the boundary of the orbit. From the individual 
just mentioned the postfrontals are missing, but the sutural borders of the frontals and of the 
parietals articulating with the postfrontals are well preserved. The jugal is a bone of con- 
siderable length, and it forms a large part of the lower border of the orbit. 
18 



274 



FOSSIL TURTLES OF NORTH AMERICA. 



The choanx are far forward. The roof of the mouth in front is vaulted, not greatly unlike 
that of a Testudo. The vomer apparently extended between the palatines to the pterygoids 
or very close to them. The distance across the palatines, at their hinder ends, is 20 mm. 
The distance across the constricted portion of the pterygoids is 13 mm. There are posterior 
palatine foramina. The lower jaw, as shown by the American Museum specimen, had a 
single sharp cutting-edge, which workt against that of the upper jaw. The lower jaw appears 
to have formed a beak in front. The symphysis is short, about \z mm. in length. The jaw is 
20 mm. high at the coronoid region. 

The right humerus is present in the Yale specimen, and complete except that the radial 
tuberosity is broken off. The length from the proximal surface of the head to the distal end 
is 83 mm. The greatest diameter of the head is 21 mm. The ulnar tuberosity is as large as 
that of Chelydra. The angle between the two tuberosities is nearly the same as in Chelydra. 
The ectepicondylar foramen also resembles that of the genus just named. The distal articular 
surface appears to have been bent toward the palmar surface more than in Chelydra. The ulna 
is like that oi Chelydra, but is, relatively to the length of the humerus, longer than in the genus 
named. It is likewise thicker from the dorsal to the palmar surface. The length is 55 mm.; 
the least breadth, 8 mm. The distal end is 19 mm. wide. The dorsal surface is strongly 
markt by ridges for the attachment of muscles. About two-thirds of the radius is preserved. 
Some portions of the hinder limbs are preserved, wholly or partly; but they have not been 
completely removed from the matrix. The right astragalo-calcaneum was found in the right 
axillary notch. It resembles that of Chelydra, but has the fibulare co-ossified with it. 

The vertebra are represented by portions of two cervicals, but they furnish us little 
information. One lies against the head of the humerus and presents a cup-shaped articular 

cavity. The centrum is 19 mm. wide, 
and there is a sharp median carina on 
its lower surface. One complete toe 
is present (fig. 339). It was found in 
the right axillary notch; but from the 
length of the phalanges and the fact 
that the right astragalo-calcaneum 
was found close to it, it is concluded 
that it is one of the digits of the hin- 
der limb. 

No. 5934 of the American Muse- 
um furnishes some fragments of the 
cervical vertebrae- One of these, a 
posterior one, shows that on the under 
side of the centrum there was a sharp 
and prominent carina. The anterior 
A posterior caudal has the centrum 




Figs. 339-341. — Baptemys wyomingensis. Limb bone.s. 

339. Digit belonging to specimen of fig. 338. Xl. 

340. Ulna. Xi. No. 5934 A.M.N. H. 

341. Terminal and penultimate phalanges. X§. No. 5934 A. M. N. H. 



end of the centrum has right and left articular cavities. 
17 mm. long. The total height of the centrum and the arches is 23 mm. The centrum is 
procoelous. The ulna is represented by fig. 340. It resembles that of Chelydra, but it is rela- 
tively broader and the radial border is thicker. Fig. 341 represents an ungual phalanx and 
the one preceding it. A considerable portion of the pelvis is preserved (figs. 342, 343). The 
upper end of the ilium is missing, but it was probably not broadened. On its anterior border, 
half the height above the acetabulum, is a strong process directed outward and forward. The 
pelvis resembles that of Testudo. The ischial symphysis is 13 mm. thick. There is a long 
antero-lateral pubic process. The pubic symphysis was more than 23 mm. long. 

Dr. Leidy's second specimen, in the U. S. National Museum, furnishes the right scapula. 
This is represented as seen from behind and of two-thirds the natural size by fig. 344. The 
height of the body above the glenoid fossa is 102 mm; the proscapular process is 54 mm. long. 

Professor Cope described from Ham's Fork, Wyoming, a species which received the name 
Baena ponderosa. The specimens are now in the U. S. National Museum, at Washington, 
where the writer has twice examined them. Cope states that his figures are three-fifths the 
size of nature; but the measurements show that they are only half that size. Cope's fig. 5 
represents the first and second right peripherals. The suture between the two is not well 



DERMATEMYDID^. 



275 



shown in the figure. His fig. 4 represents the second left peripheral. Fig. 8 is from a portion 
of the left first costal and its median notch fits accurately on the upper border of the original of 
his fig. 4. Cope's fig. 6 is almost certainly that of the right third peripheral. In the collection 
there are present the left second and third peripherals of another individual. These bones cer- 
tainly do not belong to any species oi Ba'ena. They closely resemble those of Baptemys wyo- 
mingensis, and in all probability belong to that species. 

Cope's assignment of these bones to Ba'ena was determined by the bone represented by 
his fig. 3. It is indeed very peculiar. Fig. 345 represents a section. Cope regarded it as form- 




FiGS. 342-345. — Baptemys wyommgensts. Pelvis, scapula and peripheral. 

342. Pelvis, from left side. Xj. No. 5934 A. M. N. H. it, ilium; hch, ischium; pub, pubis. 

343. Pelvis of individual of fig. 341. Seen from below. Xj. i7, ilium; <jf A, ischium; put, pubis. The suture 

between the right and left pubes ran from a point 2 mm. on the left of the leader from pub backward to 
a point 2 mm. on the left of the line of two short dashes. 

344. Scapula. X?. Specimen in U.S.N. M. 

345. Section of peripheral described by Cope as that of Ba'ena ponderosa. Xi. 

ing a part of the hinder border of the carapace, the scute seen on it being the hindermost 
one. However, the writer has found in the collection another fragment which continues the 
border 5 or 6 mm. toward the left, and on it begins another marginal scute. It is the writer's 
conclusion that this bone also belongs to Baptemys and is a malformed portion of the hinder 
border of the carapace. 

Baptemys tricarinata sp. nov. 

Figs. 346-349. 

Dermatemys , CoPE, Bull. U. S. Geol. and Geog. Surv. Terrs., vi, 1881, p. 184. 

Remains belonging to 2 individuals of the present species were collected in the Wind 
River deposits, during the summer of 1905, by the expedition in charge of Mr. Walter Granger, 
of the American Museum of Natural History. One of these, No. 6109, was found at the 
mouth of Alkali Creek, Fremont County, Wyoming; the other. No. 61 10, on the divide 
between Alkali and Poison Creeks. N0.6109 is made the type of the species. Both specimens 
are considerably fractured, neither of them furnishing a complete carapace. Taken together, 
however, the two specimens give practically the whole structure of the shell. The species is 
distinguisht from B. wyomtngensis by the possession of three dorsal carinae and a pointed 
hinder plastral lobe. 

The carapace of No. 6109 (fig. 346) has an approximate length of 460 mm.; a width of 
about 330 mm. Its structure differs only in minor points from that of fi. wyomtngensis. The 
neurals are long and narrow. The peripherals differ little from those of the Bridger species, 



276 



FOSSIL TURTLES OF NORTH AMERICA. 



except that they, like the other bones of the carapace, appear to be somewhat thinner. The 
vertebral scutes are perhaps relatively a little wider than in B. wyomingensis. There are 3 
broad dorsal carinje — a median and two lateral. The median may be traced farther forward 
than in B. wyomingensis, as far forward as the front of the third neural. The lateral carinx 
run just outside of the vertebral scutes. They are of moderate height posteriorly; on the 





Figs. 346 and 347. — Baptemys tricarinata. Carapace and plastron of type. Xj. 

346. Portion of carapace, c. p. i, first costal plate; n. i, «.8, first and eighth neurals. 

347. Plastron and portion of carapace. 

anterior half of the carapace they may be traced to the first costal; but on the three anterior 
costals they form very low ridges. 

Fig. 347 represents the plastron. The total length is 285 mm. The anterior lobe is broad, 
rounded, and slightly notcht in front. The length is 92 mm.; the width at the base, 148 mm. 
The entoplastron is larger than in B. wyomingensis, being 65 mm. long and 75 mm. wide. The 



348. 





349- 



Figs. 348 and 349. — Baptemys tricarinata. Plastron and humerus of type. X^. 
348. Anterior lobe of plastron. 349. Right humerus. 

bridge is 93 mm. wide, relatively narrower than in the Bridger species. The hinder lobe is 
105 mm. long and 1 1 1 mm. wide at the base. The sides converge backward to a point. 

The scutal areas are represented in fig. 347. No gulars are markt out; but there is a notch 
in the border of the epiplastron, as if for the crossing of the gulo-humeral sulcus. There are 
on each bridge 3 inframarginals like those of most specimens of B. wyomingensis. 



DERMATEMYDID^. 



277 



No. 61 10 has been a slightly smaller individual. Fig. 348 represents the front lobe of the 
plastron. It is somewhat more pointed in front than that of the type. What is most interesting 
is the presence of portions of the gulo-humeral sulci. The extent and position of these are shown 
in the figure. The presence of these indicates that there has occurred in this genus a coales- 
cence of the gulars and the humerals. 

Fig. 349 represents the right humerus seen from the dorsal surface. The general form is 
that of the humerus oi Chelydra. 

Baptemys iluviatilis sp. nov. 

Plate 42, figs. I, 2; teit-figs. 350, 351. 

This species is based on a chelonite which was presented to the American Museum of 
Natural History by Mr. Sidney Dillon, of New York City, in 1879. It is said to have been 
obtained by him in Colorado, but there is no record of the exact locality, nor of the formation 



35°- 





Figs. 350 and 351. — Baptemys fluviatilis. Carapace and plastron of type. X\. 
350. Carapace. Restored costal and vertebral scutes indicated by interrupted dotted bands. 351. Plastron. 

from which it was derived. The specimen probably belongs to the Bridger formation and 
there may be some error regarding the region. 

The specimen consists of a mass of gray sandstone, broken into two pieces, which bears 
considerable portions of the carapace and impressions of other portions and a fragment of the 
plastron, together with an impression of the inner surface of practically the whole plastron. 
While we must regret the absence of many parts which might evidently have been preserved, 
there is enough of the shell present to furnish us with the essentials of the structure. 

This shell has a length of 438 mm. and a width of 312 mm. The carapace (plate 42, fig. i; 
text-fig. 350) forms a high vault which rises from the lower surface of the plastron about 



278 



FOSSIL TURTLES OF NORTH AMERICA. 



Bone. 



Baptemys 
wyomingensis. 



Length. 



Nuchal 

Neural i . . 
2. . 
3- 
4- 
S-- 
6.. 

7-. 
8.. 
Suprapygal 

Pygal 



7° 
58 
47 
49 



37 
21 

'S 
»9 
28 



Width. 



160 mm. On the anterior portion of the carapace there is no median carina, but one of some 
prominence begins on the sixth neural and continues to the end of the shell. Just above the 
pygal plate this carina swells out into a considerable protuberance. The margin of the car- 
apace is nowhere reverted, except slightly so behind the posterior legs. There is a slight 
notch in the shell just over the tail. Whether or not the edges of the rear of the carapace were 
to any degree serrated can not be determined with certainty, but they probably were not. 
Anteriorly the edge of the shell is smooth ; over the neck the carapace somewhat exca- 
vated; the plastron relatively small. The lobes, especially the hinder, leave large spaces 
between the upper and lower parts of the shell. The bridge is narrow antero-posteriorly. 

The shell is rather thin in the dorsal and costal regions, from 4 mm. to 6 mm., but thickens 
toward the margin, the last peripheral being about 10 mm. thick. The surface of the carapace 
is usually smooth. 

In the middle line of the carapace we find, behind the nuchal, 8 neural plates and 2 supra- 
pygals and the pygal. The first neural is of elongated oval form. The others, from the second 
to the sixth, inclusive, are elongated hexagonal, with the broad end in front. The following 
table gives the dimensions of the nuchal, the neurals, the two suprapygals and the pygal. 
There are added the dimensions of B. wyomingensis, reduced to millimeters, from Leidy. 

The peripherals are high, the 
first being 55 mm.; the fourth, 62 
mm.; the tenth, at least 72 mm. 

The plastron (plate 42, fig. 2; 
text-fig. 351) is the most interesting 
and instructive portion of the shell. 
Since all but a mere fragment of it 
is peeled off the matrix, we must 
depend on the impressions left on 
the rock. As to the general form and 
most of the sutures, there can be no 
doubt. Its length was 282 mm. 
The anterior lobe was 100 mm. 
long, 138 mm. wide; the posterior 
lobe 79 mm. long, 112 mm. wide at 
the base. No trace is found of the 
hyohypoplastral suture; 212 mm. 
behind the front end of the plastron 
is seen the very plain impression of the hypoxiphiplastral suture. It runs outward to near 
the border of the plastron, then outward and forward, and finally turns abruptly backward to 
the border. We must, however, remember that we are viewing the upper surface of the plastron, 
and that these angulations represent processes of the bones. The xiphiplastrals had a length 
of 72 mm. and a width of 100 mm. in front. 

There are very distinct impressions of the suture of the entoplastron and of the epiplastra. 
The former was, on its upper surface, approximately circular, with a median lobe in front and 
a narrow prolongation behind. Its length was 75 mm., the width, 55 mm. The hypoplastra 
have a length of 45 mm. along the midline. 

The sulci are broad, but often extremely obscure; especially those which separate the 
vertebral scutes from the costals. The marginal sulci are usually sufficiently distinct. The 
transverse sulci of the vertebrals may be made out satisfactorily. As to the width of the ver- 
tebrals, the drawing indicates the position of the lateral sulci as well as the faint indications 
will permit. The marginal scutes did not rise on the sides as high as the peripheral bones. 
There appear to have been axillary and inguinal scutes. In B. wyomingensis there is a com- 
plete row of inframarginals. 

This species differs in various particulars from B. wyomingensis. Some differences appear 
in the hinder neurals. There are in B. fluviatilis two suprapygals; in B. wyomingensis, 
three. It will be observed from the measurements that the hindermost suprapygal is nearly 
three times as wide as that of fi. wyomingensis. There are obvious differences in the plastra, 
that of the present species being more pointed behind. 



Baptemys 


fuviatilis. 


Length. 


Width. 


63 


98 


60 


30 


47 


34 


50 


, 3> 


1 '■ 


1 ^' 


38 


34 


22 


3' 


27 


3> 


17 


38 


46 


90 


43 


29 



95 
»7 
30 
30 
30 

34 
36 

IS 
30 
34 



DERMATEMYDID^. 279 

Genus ANOSTEIRA Leidy. 

Plastron articulating with the carapace by sutures. Plastral bones 9, the entoplastron 
lanciform. Hinder plastral lobe small. Nuchal bone without costiform processes. Ten pairs 
of peripherals; 8 pairs of costals; 7 neurals. The eighth pair of costals meeting on the mid- 
line. Epidermal scutes developt at least on the carapace. The vertebrals greatly modified. 

Type: Anostetra ornata\^^\d.y. 

Dr. Leidy did not definitely refer this genus to any family, but regarded it, with Baena, 
Chisternon, and Baptemys, as apparently intermediate to the Pleurodira and the Chelydridae 
(Contrib. Ext. Fauna, etc., p. 341). Cope (Amer. Naturalist, xvi, 1882, p. 990; Vert. Tert. 
Form. West, 1884, p. 112) arranged the genus under the Chelydridae; but in the same family 
inclose relation with Anosteira he included also Claudius. He arranged Dermatemys among 
the Emydid(C. Baur (Ann. Mag. Nat. Hist., ser. ill, 1889, pp. 58, 276; Proc. Acad. Nat. Sci. 
Phila. 1891, p. 420) favored placing it with either Staurotypus or Ktnosternon, according as 
the entoplastron might or might not be found to be present. Mr. Lydekker (Cat. Foss. Rept., 
Ill, 1889, p. 143) places the genus in the subfamily Anosteirinae under the Chelydridae. Hay 
in 1902 (Bibliog. and Cat. Foss. Vert. N. A., p. 446) raised this group to family rank, but this 
had already been suggested by Baur. 

The nearly complete shell described below, presenting as it does the entoplastron, enables 
us to refer the genus definitely to the Dermatemydidae. The plastron resembles closely that 
oi Staurotypus salvinit. The presence of the costiform processes in the living members of the 
family are not regarded as being of essential importance. 

There can be hardly any doubt that Pseudotrionyx Dollo, of the Middle Eocene of Bel- 
gium, is a genus closely related to Anosteira. 

Anosteira omata Leidy. 

Plate 43, figs. I, %; teit-figs. 352-354. 

Anosteira omata, Leidy, Proc. Acad. Nat. Sci. Phila. 1871, p. 102; Ann. Report U. S. Geo!. Surv. 
Montana, etc., 1871 (1872), p. 370; Contrib. Ext. Fauna West. Terrs., 1873, pp. 174, 341, plate xvi, 
figs. 1-6. — Hay, IBibliog. and Cat. Foss. Vert. N. A. 1902, p. 447; Bull. Amer. Mus. Nat. Hist., 
XXII, 1906, p. 157, figs. 2, 3. 

Anostira ornata, CoPE, Ann. Report U. S. Geol. Surv. Wyoming, etc., 1872 (1873), p. 621 ; Amer. Nat- 
uralist, XVI, 1882, p. 989, fig. 7; Vert. Tert. Form. West, 1884, p. 128. — Dollo, Bull. Mus. Roy. 
Belgique, iv, 1886, p. 93, pi. ii, figs. 7, 8. 

This beautiful and interesting species was based originally on 4 individuals, some of 
which had been discovered at Church Buttes and others at Grizzly Buttes, Wyoming. Where 
these types now are the writer does not know. It is possible that some of them are included 
under No. 4062, of the U. S. National Museum. The specimen figured by Leidy was obtained 
somewhere in the neighborhood of Fort Bridget. It is now in the collection of the Phila- 
delphia Academy. All of his specimens appear to have come from the lower portion of level 
B of the Bridget Eocene. The American Museum expedition of 1903 found fragmentary 
specimens of the species at Grizzly Buttes and on Cottonwood Creek. The expedition of 
1905 secured at Henry's Fork a nearly complete shell, which is here described and figured 
(plate 43; text-figs. 352, 353). This comes from a higher level than the other known specimens. 

Leidy's reconstruction of this species attributed to it 1 1 pairs of peripherals. Dr. Baur 
was the first to correct this error. The complete specimen just mentioned confirms Baur's 
statement. 

The specimen found at Henry's Fork belongs to the third division of level C. It has the 
number 6132, of the American Museum. The specimen is slightly crusht. The neurals 
(fig. 352) are all missing, as well as the left front part of the carapace. In form the carapace 
is not so much excavated in front as is represented in Leidy's figure. Other specimens of the 
species show as little excavation. 

The total length of the carapace (plate 43, fig. i; text-fig. 352) along the median line is 
125 mm. The width is 105 mm. The nuchal is slightly damaged, but its length has been close 
to 20 mm. and the width the same. The free border is subacute; the thickness at the midline 



28o 



FOSSIL TURTLES OK NORTH AMERICA. 



is 5 mm. There are eight pairs of costals. Those of the seventh pair join for a short distance 
behind the seventh neural; those of the eighth pair join their full width. The costals are thin, 
about I mm. in thickness. There is a single large, roof-shaped suprapygal, whose length is 
1 8 mm. and whose width is 20 mm. The pygal has a height of 15 mm. and a width of 23 mm. 
The anterior peripherals are about 12 mm. high, at right angles with the free border. Behind 
the fifth this dimension increases until in the ninth it is 20 mm. The fourth and fifth are in 
contact with the hyoplastron; the fifth, sixth and seventh, with the hypoplastron. Fig. 354 
represents the anterior ends of the, sixth, seventh and eighth. The free border of those in 
front of the bridge is subacute; that of those behind the bridge, thin and acute. The lower 
face of the anterior peripherals is smooth, while that of the posterior is sculptured. The 
latter peripherals have a third, or inner face. This looks toward the interior of the shell and 
is concave. 

The carapace is exquisitely sculptured, the costals differently from the peripherals. The 
costals are crost, parallel with the axis of the animal, by low undulating ridges, most distinct 




Figs. 352 and 353. — Anosteira ornata. Carapace and plastron. X§. No. 6132 A. M.N. H. 

35Z. Carapace. 

353. Plastron. «nr, entoplastron; ?/>/, epiplastron; /r)'o, hyoplastron; Av^o, hypoplastron; .r/^/r, xiphiplastron. 

on the distal ends. The nuchal and the peripherals are ornamented by sharper ridges and 
pustular elevations. In general, the ridges and the rows of pustules on the proximal half of 
each of these bones run parallel with the costal border. Those on the distal half radiate from 
a focus placed some distance away from the free border. On the lower faces of the six hinder- 
most peripherals of each side the radiations extend to the proximal borders. 

The epidermal sulci are narrow and delicately imprest, but most of them may be traced. 
On the nuchal and the four anterior peripherals the intermarginal sulci can not be seen, 
owing to the sculpture. On the other peripherals the ascending sulci are easily followed, 
but the costo-marginal sulci are not visible. From this and other specimens it becomes quite 
certain that they ran along the upper borders of the peripherals, just below the costo-peripheral 
sutures. On the pygal a median sulcus ascended about half the height of the bone, then 
divided and sent a right and left into the costo-marginal sulci. The vertebral scutes appear to 
have been remarkably modified. The first has a width of 18 mm. in front. We have a right 
to look for a transverse sulcus crossing this region on the proximal ends of the first costals and 
the first neural; but there is no trace of it. Instead of this, we find that the sulcus which 





^ 



DERMATEMYDID^. 281 

usually crosses on the proximal ends of" the third costals and the third neural starts, as usual, 
on the third costals, but is carried forward so as to cross on the first neural. This sulcus in 
the specimen is very distinct; besides this, it has been observed on another specimen. 
In the median line, on the front of the first vertebral, is seen a distinct sulcus which runs back- 
ward to the hinder border of the nuchal bone. Whether or not it extended further can not be 
determined. Probably it attained to the transverse sulcus on the first neural. Apparently 
the only explanation of this condition is to suppose that the first and second normal vertebrals 
have coalesct; that the sulcus between the second and the third has been carried forward to 
the first neural and even to the nucho-vertebral sulcus; thus dividing the united first and 
second vertebrals into right and left halves. 

It seems probable that the third and the fourth vertebrals have coalesct; for no sulcus 
crosses the proximal ends of the fifth costals and the fifth neural. The vertebral occupying 
the area of the fifth in other turtles has a length of 37 mm. and a width of about 30 mm. As 
an individual peculiarity, the fourth costal scute of the left side is divided by a sulcus which 
descends on the seventh costal bone. 

Fortunately the present specimen furnishes the epiplastra and the entoplastron, elements 
not observed before (plate 43, fig. I ; text-fig. 353). The epiplastra are 37 mm. long; the width 

is 13.5 mm. at the middle of the length. They narrow ante- 
riorly. The entoplastron is 19 mm. long, pointed in front, 14 
mm. wide behind. These parts resemble considerably those 
of Staurotypus salvtnii (Boulenger's Chelonia, p. 31, fig. 10) 
but the entoplastron is more pointed in the fossil species and 
Fig. sS'^.-Anosteirn nrnnfa. Ante- "^^ epiplastra are not so prolonged at their hinder outer 
rior ends of three peripherals, angles. 

No. 61 52 A. M. N. H. The whole length of the plastron is 86 mm. The bridges 

have a minimum width of 15 mm. It joins the peripherals 

;r, sixth peripheral: y, seventh: 2, eiehth. 1 t^, 11 1 j 

>^ '^ ' ■" > ' 6 [jy coarse sutures. 1 he hyoplastron is only 4 mm. wide 

on the bridge. Its greatest fore-and-aft breadth is 1 1 mm. The fore-and-aft extent of the 
hypoplastra is 21 mm.; that of the xiphiplastra, 27 mm. 

The bones of the plastron are markt by fine ridges and intervening grooves. On the 
epiplastra these radiate from a point near the inner border, near the hinder end. On the 
bridge the sculpture is transverse to the length of the body. 

Neither on this specimen nor on any others has the writer been able to find evidences of 
epidermal scutes on the plastron. Doubtless these were present, but they were so delicate that 
their boundaries have left no impressions on the bones. Dr. Baur could not find the sulci on 
the plastron of specimens at Yale. 

Cope has mentioned the finding of specimens of this species on the "Upper Green River." 
No. 1059 of the American Museum of Natural History bears his label to the effect that it was 
found on Green River, at the mouth of the Sandy. The strata here belong to the lowest level, 
A, of the Bridger. These have furnisht also Amyda cerjuo. Cope's specimen is somewhat 
differently sculptured from the specimens from a higher level, the pustules predominating 
over the ridges, on the peripherals. It is, however, probably not a distinct species. 

The evidence at hand shows that this species ranges from the lowest level of the Bridger 
beds to the top of that known as C. 

Anosteira radulina Cope. 

Anosttra radulina. Cope, Palaeont. Bull. No. 9, 1872, p. 555; Proc. Amer. Philos. Soc, xii, 1872, p. 555; 

Ann. Report U. S. Geol. Surv. Montana, etc., 1872 (1873), p. 620; Vert. Tert. Form. West, 1884, 

p. 128, plate xviii, figs. 18, 19. 
Anosteira rai/w/a^a, Baur, Ann. Mag. Nat. Hist. (6), III, 1889, p. 273. 
Anostira radiolata, hyuEKKEK, Cat. Foss. Rept., in, 1889, p. 144. 
Anosteira radulina. Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 447. 

This species was described by Cope from two peripheral bones, one from in front of the 
bridge, the other from behind it. These are now in the U. S. National Museum and have the 
number 4096. They were found in the Bridger Eocene near Ham's Fork, Wyoming, there- 
fore in the lowest division. A, of the formation. The individual that furnisht these bones was 



282 FOSSIL TURTLES OF NORTH AMERICA. 

estimated by Cope to have been about twice the size of the specimens of A. ornata that had 
then been found. He concluded that it belonged to a distinct species for the reason that the 
sculpture had not increast in coarseness corresponding to the increase in size of the animal. 
This, however, is not a sufficient reason. Since the bones increase in size by additions to their 
borders, the lines and pits of the sculpture once formed will not change in coarseness. A better 
reason for regarding the bones as those of a species different from A. ornata is to be found in 
their form. The anterior peripheral, the first of the left side (Cope's fig. 18), has the form of a 
rhomboid, quite different from that of any anterior peripheral oi A. ornata. The lower side of 
Cope's figure is that of the free border of the bone. The thickness of the bone is 7 mm. The 
hinder peripheral appears to be the ninth or tenth. It is 7 mm. thick and its free edge is obtuse. 
In A. ornata, on the contrary, it is acute. 

The length of the anterior peripheral, along the free edge, is 25 mm.; its height is 28 mm. 
Both these dimensions in the hinder peripheral are 25 mm. The sculpture of the anterior bone 
is stated to consist of closely packt vermicular ridges which run out flat on the posterior and 
upper borders. In the posterior the ornamentation consists of closely placed minute tubercles 
over the whole surface, these being more or less confluent on the posterior and upper borders. 

Mr. R. Lydekker has described and figured a species called Anostetra anglica, from the 
Lower Oligocene of Hordwell, England (Cat. Foss. Rept., iii, p. 143, figs. 34, 35). Dr. G. 
Baur (Ann. Mag. Nat. Hist., in, 1889, p. 273) has stated that this can not be distinguisht from 
Cope's A . radulina. A glance at the figures of the two forms shows that they can not be 
identical, the sculpture of the English species being far coarser. In A. ornata the suture 
between the hypoplastron and the xiphiplastron, in crossing from the free border to the mid- 
line, runs first forward, then backward, then forward again. In the English species it runs 
obliquely, but directly, inward and forward. It is not probable that two species of the same 
genus would be so different. 

Genus XENOCHELYS Hay. 

Characters drawn from the type and only known specimen. Neurals 6, the 4 anterior 
having the narrow end directed forward. Only 7 pairs of costals; those of the sixth and 
seventh pairs meeting at the midline. Ten pairs of peripheral bones, and 11 pairs of marginal 
scutes; the nuchal scute very small. Plastron joined to the carapace without buttresses. 
Bridge narrow. Only 5 pairs of plastral scutes. Two inframarginals on each bridge. 

Type: Xenochelys jormosa Hay. 

This genus differs from Dermatemys in having no axillary or inguinal buttresses; 5, 
instead of 6, pairs of plastral scutes; and in the form of the anterior neurals. In the reduced 
number of peripheral bones and marginal and plastral scutes it resembles Staurotypus. In the 
latter genus, too, 3 of the anterior neurals have the narrower end directed forward. The 
width of the bridge of Xenochelys is intermediate between that of Dermatemys and that of 
Staurotypus. The two genera just mentioned, as well as Claudius, the nearest living relatives 
of Xenochelys, are inhabitants of Central America. 

Xenochelys formosa Hay. 
Text-figs. 355, 356. 
Xenochelys jormosa. Hay, Bull. Amer. Mus. Nat. Hist., xxii, 1906, p. 29, figs. 2, 3. 

Of this species there is at present known only the specimen which serves as the type. This 
was discovered in the year 1904, at Quinn Draw, Washington County, South Dakota, by Mr. 
Albert Thomson, of the American Museum of Natural History. The deposits in which it was 
found belong to the lower division of the Titanotherium beds of the White River Oligocene. 
The specimen consists almost wholly of the shell, and this is somewhat crusht. The plastron 
is driven upward into the carapace, and a small portion of the left margin of the carapace is 
wanting. The whole structure of the shell can nevertheless be determined. 

The length of the carapace (fig. 355), measured in a straight line, is 200 mm.; the great- 
est width 129 mm. The shell is therefore slightly narrower proportionally than that of 
Dermatemys mawii. The height was moderate. A low rounded carina is found on the nuchal 



DERMATEMYDID^. 



283 



and another on the hinder end of the carapace. There are slight traces of a lateral carina on 
each side, along the outer borders of the vertebral scutes. In outline the carapace is slightly 
excavated in front and notcht behind. The borders behind the inguinal notches were very 

slightly flared upwards. The nuchal bone is well developt, hav- 
ing a length and breadth each of 38 mm. There are no costiform 
processes. Of the 6 neurals the anterior 4 are hexagonal, with 
the narrower end directed forward, a somewhat unusual thing 
among both Cryptodire and Pleurodire turtles; nevertheless 
occurring, according to Dr. Boulenger's figures, in the case of some 
of the neurals of Staurotypus, Kinosternon, Cyclemys, Geomyda, 
and Cyclemys. The sixth neural of our species is quadrate, the 
seventh is triangular. The table gives the dimensions of the 
neurals. 

Behind the costals of the seventh pair there is a single suprapygal, 22 mm. long and 38 mm. 
wide. This is succeeded by the notcht pygal, which has a length of 23 mm. and a width of 
28 mm. 



Neural. 


Length. 


Width. 


I 


15 


■5 


2 


ig 


16 


3 


18 


16 


4 


16 


■3 


5 


IS 


10 


t> 


g 


II 



355- 





Figs. 355 and 356. — Xenochelys formosa. Carapace and plastron of type. xj. 

355. Carapace. 

356. Plastron, an, anal scute; ent, entoplastron; epi, epiplastron; fern, femoral scute; 

g, supposed gular scute; hum, supposed humeral scute. 

As already stated, there are only 7 pairs of costal plates, of which the two hindermost 
pairs reach the midline of the shell. The anterior pair is well developt, having an antero- 
posterior width of 35 mm. The costals are about 3 mm. in thickness. 

The peripheral bones are relatively large, and there are only 10 of them on each side. The 
second measures 26 mm. from the free border to the union with the costal plate; the third, 
35 mm. The free borders of the anterior and posterior peripherals are acute. They attain 
a maximum thickness of about 9 mm. The sulci bounding the epidermal scutes are moderately 
imprest. There is a very small nuchal scute. The vertebral scutes have a width each of about 



284 FOSSIL TURTLES OF NORTH AMERICA. 

35 mm. The first has a length of 45 mm. In form the vertebrals resemble those oi Staurotypus 
salvtnii. Along the hinder ends of each of the lateral borders of the three anterior vertebrals 
there is a very deeply imprest groove. In the case of the first and second vertebrals these 
grooves extend backward on that neural bone which is crost by the hinder border of each ver- 
tebral respectively. The grooves along the third vertebral scute run backwards on the prox- 
imal ends of the costals of the fifth pair. 

The marginal scutes rise relatively little above the free borders of the shell, the second 
having a fore-and-aft extent of only 13 mm.; the tenth, of only 15 mm. The costal scutes are 
therefore relatively broad. 

The plastron (fig. 356) has a total length of 163 mm. Where narrowest, the bridge has a 
width of only 43 mm. The axillary and inguinal notches are very narrow. The plastron was 
united with the carapace by a close suture, but there are no buttresses rising from the plastron. 
The anterior lobe has a length of 52 mm. and a width of 80 mm. at the base. It is broadly 
rounded in front and somewhat repand. The border is acute. The entoplastron is broadly 
oval, 29 m