49. KINOSTERNON 971 
large, somewhat pointed, covered with smooth skin. Chin 
and throat with a few barbules. Limbs covered with smooth 
skin except close to toes; anterior with five, posterior with 
four toes, completely webbed. Tail of moderate length, end- 
ing in a horny nail or claw. 
The carapace is yellowish olive, the plastron lighter, yel- 
lowish. The horny plates are margined with dark brown, 
especially along their posterior edges, above. The head and 
neck are olive above, yellowish below, sometimes with a 
light yellowish streak along the side of the neck, but with 
little if any marbling or mottling, the chin and throat 
especially being usually immaculate. 
Length of carapace... 85 97 107 7, 120 131 
Length of plastron__... teh 82 oF 99 97 105 
Width of carapace... 65 i?) 86 81 84 92 
Width of plastron_.. =55\5 56 67 65 69 72 
Remarks.—Series of specimens of this and the preceding 
species show much variation in size, shape and coloration. 
Both species have been recorded from Arizona; indeed one 
of the types of K. flavescens was said to have come from the 
Gila River near Fort Yuma. Nevertheless, I incline to the 
opinion that it ultimately will be found that all Arizonan 
specimens represent one variable species or subspecies, those 
of Texas, another. Variation is great and identification diffi- 
cult. Texan specimens (K. flavescens) have fewer barbules 
on the chin and neck, especially on the lateral fold, and the 
skin of the neck is less granular than in Arizona specimens 
(K. sonoriense). The shell in Texas specimens often is 
more rounded and smoother, with less evident dorsal ridge. 
The pectoral plates usually have a shorter median suture 
than is seen in Arizonan examples. The color of the shell in 
K. flavescens, usually is a little more yellowish and the dark 
margins of the plates more distinct. The neck and chin are, 
