PEOCEEDINGS OF UNITED STATES NATIONAL MUSUEM. 443 



ward; lower lid about three times as broad as tlie upper. Jaws short 

 and thick: sheaths short and deep, that of the upper jaw eudiug under 

 the middle of the eye ; a depression beneath the eye. The two tooth-like 

 X)roeesses at the symphysis of the lower jaw large and high, giving the 

 cutting margin a concave outline. 



Anterior extremities not greatly larger than the posterior, frequently 

 comi)rcssed in the anteroposterior direction, but sometimes nearly 

 terete. Five claws with stout nails. The whole anterior surface of the 

 leg covered with A'ery large rounded scales, approximately equal iu 

 size. Scales on the sole of the foot large. 



The posterior extremities are terete and chivate, and bear four flat- 

 tened, pointed nails. Scales on the heel large, two especially so. 



Color of the carapace yellowish-brown, the surface within the smaller 

 stria of each plate yellow. Sternum light dirty yellow. Ilead and legs 

 yellowish gray. Jaws yellowish. 



Specific distinctions. — The main diiferences which separate X. 

 Berlandieri from X. polyphemus and X. Agassizii relate to the size and 

 shape of the head and jaws, the size and shape of the legs, and to the 

 height of the shell. In X. polyphemus the length of the carapace is 

 more than twice the height of the shell, while in X^. Berlandieri the 

 length of the former is considerably less than twice the height of the 

 latter. In the former species the fore legs are largest at the extremity, 

 while in the latter they are largest at the knees. In X. polypliemus again 

 the cutting edge of the lower jaw is nearly straight, while in X. Ber- 

 landieri it is very considerably arched, giving the mouth a liawlc's Mil 

 aj)pearauce. Many other minor differences exist in the arrangement of 

 scales on the legs, and the like. 



Size. — Of the three species, X. Berlandieri is the smallest. The 

 adults of X. polypliemus and X. Agassizii are of about equal size. The 

 following table gives the actual measurements of greatest length and 

 breadth of six adult si>ecimens : 



Species. 



Locality. 



ft-a 



Inches. 



4 



4i 

 32 



X. polyphemus : 



No. ... 



No. 9627 



Ko. (XJ) 



X. Agassizii: 



No. 10412.*.. 



No. ... 



X. Berlandieri: 



No. 8926a 



No. 89266 ... 



Florida 



Nashville, Ga . 



Fort Yuma, Cal.. 

 , Cal 



Brownsville, Tex 

 Brownsville, Tex 



Allied genera. — The Brazilian Tortoise, CJielonoidis tahulata, in- 

 habiting the northern parts of the neotropical region, although resem- 

 bling, when half grown, the species of Xerohafcs, differs from them all 

 in characters of generic value, such as the absence of a nuchal ijlate, 



