TESTUDINATA. 
73 
not so large as some specimens of C. serpentina. Tire width at its 
front end is 30 mm.; while that of a specimen of C. serpentina, 
with carapace 240 mm. long, is hardly 20 mm. The greatest thick¬ 
ness, at the hinder end, is 13 mm.; in the case of C. serpentina, 
only 6 mm. In individuals of C. serpentina there is a narrow 
ridge, sometimes obsolete, usually inconspicuous, which runs along 
on the bridge peripherals from the free border in front to that 
behind. In the species here described this ridge is very prominent. 
The surface above this ridge is much flatter than it is in the ex¬ 
isting snapping turtle. The border of the bone below the keel 
mentioned is 12 mm. wide; in the specimen of C. serpentina used 
for comparison, only 6 mm. wide. The surface of the type bone 
is smooth. 
A bone numbered 5943 (pi. 6, fig. 7) is the left eighth 
peripheral. Its length is 44 mm.; its width at the middle of the 
length is 34 mm., the thickness 11.5 mm. In the carapace of C. 
serpentina used for comparison these dimensions are respectively 
31 mm., 16 mm., and 5.5 mm. The upper surface is somewhat 
flatter, the lower considerably more convex than in C. serpentina. 
The eighth and-ninth marginals at their junction are 21 mm. high; 
in C. serpentina, 15 mm. 
Another hinder peripheral, No. 5508, seems to be the tenth of 
the left side. It is shorter than the one last described, only 3 0 
mm. The width is nearly the same at the two ends, 29 mm., bm 
the upper edge is slightly eroded. It may have formed a jagged 
suture with the costals. The thickness is 11 mm. The surfaces 
are smooth. There is no notch in the free border where it is 
crossed by the sulcus between the corresponding marginals, differ¬ 
ing in this respect from most specimens of C. serpentina; but in 
old individuals the notches, except the one in the eleventh peripheral 
of each, are often wanting. 
CHELYDRA SCULPTA, NEW SPECIES. 
Plate 4, fig. 7; Plate 6, figs. 8-9. 
Type-specimen. —A ninth right peripheral, No. 5510 of the 
Florida Geological Survey. 
Type-locality and formation .—Vero, St. Lucie County, Flor¬ 
ida. Pleistocene. 
Diagnosis .—Ninth peripheral not so thick as that of C. iati- 
