lU Mr. E. I. Pocock on the 



gradations in the specialization of the feet of Felis in the 

 following particulars : — 



Claw-sheaths. — In their simplest form, as exemplified 

 in Felis sylvestris or F. geoffvoyi, these structures differ iu 

 no essential respects from those of some genera of Viverrin&e^ 

 like Viverra and Genetta. 



In their most elaborate form, as exemplified in Felis lijnx^ 

 Panthera tiyris, and others, the inner lobes on all the digits 

 are well developed and form claw-sheaths, complete extern- 

 ally and internally, but the extent to which they protect 

 the tips of the retracted claws depends upon the de;4ree of 

 retraction of the claw-bearing phalanx by the elastic liga- 

 ments and upon the length of the sheaths themselves. 



Between these two extremes every gradation in the 

 development of the sheaths may be traced. 



Webs. — The webs may, exceptionally, be very shallow, as 

 in the hind feet of F. caracal, but in almost all cases they 

 reach up to the proximal end of the digital pads, at least on 

 their admedian side; but in other cases they extend beyond 

 that point, and may, in the case of the front foot, reach 

 practically to the distal end of those pads on the admedian 

 side and exhibit only a slight emargination of the edge, as 

 in F. tigrina, for example. In the hind feet the webs are 

 always shorter than in the fore feet, but they exhibit a 

 similar progressive series in development from species to 

 species. In almost all cases well-developed webs are asso- 

 ciated with well-developed claw-sheaths. A striking excep- 

 tion to this, however, is shown by the hind feet of F. lynx, 

 where short and deeply emarginate webs accompany claw- 

 sheaths, which are complete both externally and internally. 



It is needless to compare the feet of the Felidse with those 

 of Hyana, Munyos, Galidia, Eupleres, Cryptopi'octa, Nan- 

 dinia, Faradoxurus, and their allies. But a few genera of 

 ^lui'oids, foru;erly included in the heterogeneous family 

 Viverridae, approach the Felidae tolerably closely in the 

 structure of the feet, and, at all events, in the develop- 

 ment of claw-sheaths, have more "feline" feet than has 

 Acinonyx. 'Ihere is scarcely any diffeience, for example, 

 between Genetta* nwd. many species of /^6'/zs in the extent 

 to which the claws are retiacted and guarded by cutaneous 

 sheaths. Tl.e same may be said of the feet oi Lin sang and 

 Poiana j. l^ut in the structure of the plantar and carpal 

 pads, the low-set pollex, and the presence of the hallux, 



♦ Proc. Zoo]. Soc. 191o, p. 13B, fijr. 3. 



t Ann. & May. iSllI. liist. {fi) x\i. pp. 342 & o45, pi. xii. (1015). 



