394 



MR. R. I. rOCOCK ON THE EXTERNAL 



outer lobe, which is also very large, has separated itself from the 

 main mass of this pad and travelled up the foot in company with 

 the fifth digit, as in Chinchilla ; and, as in the case of the front 

 foot, the hairs of the sides encroa.ch laterally more over the sole 

 than in GhincJiilla. ("Text-fig. 15, C, D.) 



In Lagostomus the fore foot difl'ers from that of Chinchilla 

 and C(elogen]/s in the suppression of the pollex, but is otherwise 



Text-fio-ure 14. 



A. Eiiglit liind foot of CMncMUa Janic/era. 



B. „ fore „ „ '„ 



C. „ hind foot of Lagostomus trichodactijlus. 



D. „ fore 



tolerably similar in type, with adaptations for a life in the open 

 plains as opposed to a i-ocky or forest habitat. The digits are 

 shortish with well-developed pads and claws ; the third and 

 fourth are subequal and longer than the second and fifth : 

 the second also is longer than the fifth, but not quite to 

 the same extent as in Chinchilla and Ccelogenys. They are thus 



