784 MAMMALIAN ANATOMY 



(b, c) Middle and Distal phalanges as in the second digit. 

 On the Fourth Metatarsal, the origin of the third plantar and 

 fourth dorsal interosseous muscles. 

 On the Fourth Digit : 



(a) Proximal phalanx, the insertion of the third plantar and 



fourth dorsal interosseous muscles. 



(b, c) Middle and Distal phalanges as in the second digit. 

 On the Fifth Metatarsal, the insertion of the abductor ossis meta- 

 tarsi minimi digiti, the peroneus brevis, the opponens minimi digiti, 

 and the origin of the fourth plantar interosseous muscle. 

 On the Fifth Digit : 



(a) Proximal phalanx, the insertion of the fourth plantar in- 

 terosseous muscle, the adductor minimi digiti, the abductor 

 minimi digiti, and the peroneus tertius. 

 (b, c) Middle phalanx and Distal phalanges as in the fourth 



digit. 



The tendons of the lumbricales join the tibial side of the extensor 

 tendons of the third, fourth, and fifth digits. 



VARIATIONS IN THE FOOT. 



Polydactylism affecting the foot of the cat appears to be not un- 

 common, although I have not been fortunate enough to meet with 

 examples of it. 



The following classification, as well as the figures, are taken from 

 Bateson. 1 



In all cases the abnormality is confined to the tibial side of the 

 foot ; the three outer toes are always normal. The tarsal bones may 

 be normal, but more commonly on the tibial side of the mesocunei- 

 form there are two cuneiforms, entirely separate or more or less joined 

 together and with the mesocuneiform. In one specimen the scaphoid 

 was divided, and each half articulated with two cuneiforms. 



The examples of polydactylism in the cat's foot may be arranged 

 in three groups : 



1. The foot has five toes ; the first toe, on the tibial side, has three 

 phalanges, and, inasmuch as the terminal phalanx can be retracted to 

 the tibial side of the middle phalanx, is formed like a toe of the op- 

 posite foot. The second toe also has three phalanges, but the terminal 



1 Materials for the Study of Variation, p. 314. 



