50. CLEMMYS 975 
Young with a median dorsal ridge not present in adults. 
Vertebrals five, broader than long. Costals four, first long- 
est, second highest, last smallest. Nuchal very narrow. 
Marginals 12 on each side, supracaudals being distinct. Plas- 
tron large, extending forward about as far as carapace, 
weakly notched posteriorly, truncate anteriorly. Its gular 
plates smallest, triangular. Pectorals not much smaller than 
abdominals. Anals large, median suture between them longer 
than that of any other plastral plates. Bridge formed of 
pectoral and abdominal plates. Axillary and inguinal plates 
very small or absent. Head large, more or less flat-topped, 
covered above and laterally with smooth skin. Upper jaw 
not hooked, sometimes notched at symphysis. Skin of neck 
and gular region granular. Limbs covered with scales; an- 
terior with five, posterior with four digits webbed to bases 
of long claws. Tail moderately long, tapering to tip, cover- 
ed with scales in irregular whorls, 
The coloration is very variable. In some specimens the 
carapace is olive or horn-color with few or no markings. In 
others a few broken and very irregular black lines are pre- 
sent. These lines frequently have become so numerous that, 
blending and crossing, they appear as the ground color, or 
form a very fine network through which the original ground 
color shows more or less indistinctly. Sometimes the cara- 
pace is almost black. The plastron is yellow, usually irregu- 
larly blotched with black or brown, or with dark lines along 
the posterior margins of the plates. The upper surface of 
the head may be unicolor or finely or coarsely reticulated with 
yellow and black. The chin and throat are yellow, often 
dotted with brown or black. The limbs and tail are yellow 
marked with black or brown, or brown marked with yellow. 
In young, the plates of the carapace show a central area of 
brown sometimes surrounded by a band of lighter brown or 
