1198 MR. R. I. POCOCK ON THE EXTERNAL CHARACTERS 



f. Feel of the Sousliks and Marmots. 



A second group of Ground Squirrels represented by the 

 Sousliks {Gitellus) and the Marmots [Cynomys, Marmota) have 

 feet like those of Xerus and its allies in that the third digit is 

 the longest, and the second and fourth digits not so unequal, as in 

 the arboreal Squirrels, and the claws longer, stouter, and less 

 curved. The three genera in question, however, have very 

 different feet. 



The fore foot of Gitellus {Otospermophilus) beecheyi*, judging 

 from a dried skin, is shorter and broader than that of the 

 typical squirrels, and is naked below. The fourth digit is 

 decidedly but not much longer than the second. The three lobes 

 of the plantar pad and the two carpal pads are well developed, and 

 the pollex is represented by a conspicuous nail attached to the 

 outer side of the inner carpal pad in front. In the hind foot the 

 second, third, and fourth digits are nearly equal, the third only 

 slightly surpassing the others, which are subequal ; the fifth 

 reaches beyond the middle of the fourth ; the plantar pad is 

 represented by four well-developed contiguous lobes, the inner 

 and outer of which are set rather far back, the greater part of 

 each lying behind the other two. There is no trace of metatarsal 

 pads, the whole area being covered with hair from the heel to the 

 plantar pad. (Text-fig. 54, A, C.) 



Judging from Miller's description of the European species 

 Gitellus citellus, the feet of that species agree tolerably closely 

 with those of C. heecheyi. He says, however, that in the fore 

 foot the second and fourth digits are subequal, and that the fifth 

 extends only a little beyond the base of the fourth. This does 

 not apply to C. heecheyi. Similarly, he states that in the hind 

 foot of G. citellus the fifth digit extends just beyond the base of 

 the fourth, and the hallux not quite to the base of the second 

 digit. This is not true of G. heecheyi. But the apparent differ- 

 ences between the two species in the particulars mentioned are 

 interesting, if true, because in the relative length of the digits the 

 typical European species seems to approach the genus Gynomys f. 



In Gynomys the fore foot is long and robust, almost as large 

 indeed as the hind foot. The digits are thick and the claws long. 

 The second digit is a little longer than the foui-th, and the fifth 

 reaches a little beyond the base of the fourth. The inner and 

 outer lobes of the plantar pad are small, and together hardly 

 equal the size of the wide median lobe. The outer carpal pad is 

 large and the inner is rather prominent internall}^, and gives 

 support to the claw of the pollex, which is as long as that of the 

 second digit. The entire sole is naked. In the hind foot the 

 second, third, and fourth digits ai-e subequal, the third only very 

 slightly surpassing the others, as in Gitellus. The fifth is set 

 almost as far back as the hallux and is only a little longer, 



* A Californian species. 



f For a possible explanation of these discrepancies, see note, p. 1208. 



