CHELONIID. 2 
The writer has been permitted to examine these specimens thru the courtesy of the 
present state geologist, Prof. William 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 lotis 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 Amyda virginiana 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. 1, 2; text-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. 1). 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 2mm. 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. 
