42 ]NTEODUCTION. 



In tlie Pelobatidx and Bufonidse the inner centrale is 

 in contact with the radius. 



Fig. 17. 





Cavpus of — A. Bombinator pachypus. B. Pelodyies punctatus. 

 c. Rana temporaria. (After Howes and Ridewood.) 



B. Radius. U. Ulna. r. Radiale. u. Ulnars, c. Centrale. 

 1 — i. Distal tavsalia. I — V. Digits. 



There are four functional fingers, with elongate 

 metacarpals, and 2, 2, 3, 3 phalanges. The distal 

 phalanx is pointed or slightly expanded at the end, 

 somewhat as in the human skeleton; or bears a well- 

 marked transverse branch, giving it a T-shaped 

 appearance, as in B. greeca ; or it assumes a peculiar 

 claw-shaped conformation in the Hylidse, which is 

 described and figured above, p. 15. In addition to 

 these four fingers there is a rudimentary thumb or 

 pollex, usually more developed in males than in 

 females, and which, besides its metacarpal, may show 

 one or two ossicles representing phalanges. The meta- 

 carpal of the pollex is very strongly developed in 

 the male Discoc/Iossus, which is also remarkable for the 

 enlargement of the second metacarpal, bearing a crest 

 along the inner side. 



The pelvis (Fig. 18) is much elongate, and shaped 

 like a pair of tongs, the free extremities of which are 

 attached to the diapophyses of the sacral vertebra. 

 The lateral branches ai'e formed by the ilia, which, 

 with the ischia behind them, bound the acetabulum; 

 the third element, the pubis, situated ventrally be- 

 tween the ilium and the ischium, is often cartilao-inous 

 or calcified, and absent in Bombinator. In Pelobates 



