400 



JIR. n. I. I'OCOCK ox THE EXTERNAL 



The hind foot difters from that of Cavia iu the webbing of 

 the digits and the hoof-like claws, which are like those of the 

 fore foot, except that the webs are wider and, owing to the more 

 backward position of the plantar pad with its two horny''plates, 



Text-fiffiu'e 18. 



A. Right fore foot of Ctenodactylus gnnd't. 

 15. „ hind „ 



C. Iiiiiev or second digit of hind foot of same, showing combs. 



D. Right fere foot of Ctenomys mendocinus. 



E. „ liind „ „ „ 



F. Tip of second digit of hind foot of same, showing combs. 



appai'ently longer. The metatarsal area resembles that of Kerodon 

 i\\ having the posterior three-fourths of its length covered by a 

 thick horny plate. (Text-fig. 17, C.) 



