220 REPORT OF NEW JERSEY STATE MUSEUM. 
aa, Carapace more or less keeled, at least when young; head very large, with 
strong jaws; plastron with its posterior lobe longer than anterior, trun- 
cate behind, and its posterior angles not rounded; lobes of plastron little 
movable, incapable of closing shell. TERRAPENE 
Genus KINOSTERNON Spix. 
The Mud Turtles. 
Kinosternon pensylvanicum (Gmelin). 
IPPATE SOS 
Mud Turtle. Mud Digger. Musk Turtle. 
Carapace slightly ovoid as viewed above, with greatest width 
‘about first third in its length, or about opposite middle of second 
vertebral plate. Anterior margin of carapace barely indented. 
Carapace when viewed laterally with greatest depth about third 
vertebral plate, and posterior descent of profile much more 
strongly convex than anterior, which slopes gradually down in 
front. Median vertebral keel broad, obsolete, and hardly defined. 
Posterior surface of carapace abruptly vertical, and marginal 
plates also all sloping down, none jutting out, though those along 
anterior edge a little more obliquely inclined. Lower edge of 
carapace as seen in profile posteriorly straight, and. laterally 
slopes gradually up forwards, at first somewhat convex till nearly 
horizontal a short space before neck. ‘Two plates forming bridge 
of plastron deepest at their articulation, so that their length would 
be 34 their depth. Axillary plate narrowly exposed. Inguinal 
plate large and elongate. Plates of carapace smooth or with 
only very obsolete traces of striz. Plastron ovoid, with a 
marked constriction just behind bridge, so that greatest width 
would fall near first third of its length or just before bridge. 
Front of plastron convex, and each side converging back towards 
bridge convexly. After constriction just posterior to bridge, each 
side of plastron bulges out with a notch at junctions of femoral 
and anal plates, and also a triangular one medianly at junction 
