1888.] THE CARPUS AND TARSUS OF THE ANURA. 169 



The pre-hallux is present iu all specimens examined by us ', and 

 it consists in them of four segments — a proximal larger one or 

 tarsal {ph. i.), a smaller metatarsal, and two diminutive phalanges^. 

 The retral process of the second or metatarsal segment (* of fig. 19) 

 is absent in Phijllomedusa (fig. 19a). In an old specimen of Hyla 

 lichenata, on the other hand, it was completely segmented off on 

 either side, forming (woodcut, fig. A, p. lol) the largest of a series 

 of nodules which fringed the free border of the pre-hallux fold. 

 We have already discussed the probable significance of these. 



d. BUFONID^. 



Examined : — 



Bufo vulgaris. 



Bufo viridis : large specimen. 

 Bufo calamita : 8 young. 

 Bufo variegatus : young. 

 8 Pseudojfliryne bibronii. 



Fore Foot (fig. 22). 



The limb-skeleton of Bufo has been described by various authors ; 

 it was first figured by Brandt and Ratzeburg (8), and subsequently 

 by Mayer (27). Gegenbaur, Owen, Born, and Wiedersheim have in 

 turn dealt with this skeleton, and upon some of their observations 

 we have already commented. 



Pseudophryn& (fig. 22) is exceptional among the members of this 

 family in the characters of its carpus : in Bufo the uaviculare («) 

 articulates directly with the radius, and lies in the proximal row, 

 here it is comparatively small and central : in Bufo the 3rd and 

 4th carpalia and our postaxial ceutrale coalesce to form a capitato- 

 hamatum, as in the Common Frog. In Pseudophryne there are 

 three carpals lying to the inner side of the large capitatura (4 k), 

 whence it follows that cp. 3 is distinct as in Pelodytes. The carpus 

 of Pseudophryne approximates more nearly towards that of Pelodytes 

 than any other genus yet examined ; and considering that the 

 Bufonidce are, with respect to the confluence of their distal and 

 postaxial central elements, a stage in advance of the Pelobatidce, 

 Pseudophryne is to them what Pelobates is to the latter. 



Hind Foot (fig. 23). 

 We can confirm Bom's statements concerning the tarsalia in this 

 family (3, p. 443) regarding the homology of the element marked 

 (2, 3) with the tarsalia of the second and third digits, and we find 

 that in old specimens this may become shortened-up in a manner 

 suggestive of the Tree-Frogs. We have nothing to add to what we 

 have already stated in confirmation of Gegenbaur's observations con- 

 cerning the ligamentous 4th tarsal {cf. p. 145). 



^ Leydig states that he was unable to find its cartilaeres in H. arbo^ea (25 

 p. 181). 



^ Born has described and figured the details of ossification of these, subsequent 

 to fusion, in a very old specimen of H. arborca (6, pi. 1. figs. 1 and 2). 



