1888.] THE CARPUS AND TARSUS OF THE ANURA. 165 



According to Born (6, p. 62) the rudimentary poUex may, in^om- 

 binator, either bear two phalanges or be wholly al)sent. In all our 

 specimens we find that it bears two segments (^Jo. ii. & iii.), irrespec- 

 tive of its carpal {po. i.). In Discoglossus and Alytes there is but 

 one segment other than the carpal present ; in the male Biscoglossus 

 this becomes fully ossified and expanded. 



During ossification of the leading elements in Discoglossus, a cen- 

 tral deposit takes place in each {I. n. fig. 5) ; soon, however, a difi^er- 

 entiation of the ossific centre into a superficial spongy annulus and 

 a central denser core takes place (pk, fig. 5), leading up to the 

 curious condition of the adult bones (fig. 6) already noted (p. 143). 



Hind Foot {^gs. 8 & 10). 



Gegenbaur was in error in asserting (IS, p. 60) that in Bombinator 

 the separation between the astragalus and calcaneus is complete. 

 In even the youngest larva examined by us these two elements had 

 already become confluent, bearing a common expanded epiphysial 

 cartilage. 



Born claims for the same genus (6) a range of individual variations 

 in the tarsalia far exceeding anything which we have observed. In 

 all our specimens the tarsalia of digits 1, 2, & 3 are distinct, that of 

 the third being invariably the largest. Tarsalia 4 & 5 are represented 

 by a ligament, which in dlytes alone carries a nodule of hyaline 

 cartilage (p. 145). 



The naviculare (centrale, n) is, in all, large, and so placed as to 

 separate the hallux-tarsal (1) from the astragalus, the epiphysial 

 end of which is excavated so receive it. This element is always the 

 first to ossify, the calcar follows, tarsaUa 1, 2, 3 remaining for a con- 

 siderable time unossified. 



The calcar never consists of more than two segments, and is in all 

 small. Born, in opposition to Leydig, regards the solitary piece 

 present in Alytes (fig. 10, ph. i.) as the metatarsal (our tarsal) -|- the 

 phalanx of the sixth toe. "We have been unable to detect the pre- 

 sence, at any stage, of a second segment ; we hold, therefore, that the 

 element in question is really the hallux-tarsal. 



b. PELOBATIDiE. 



Examined : — 



Xenophrys monticola: 3 specimens measuring respectively 



70, 40, and 26 mm. 

 Pelodytes pu7ictatus : 3 adults and a tadpole. 

 Pelobates fuscus : an adult <S and one very young specimen. 



Fore Foot {^g&. 11, 14, 15, 16, 18). 



That which most characterizes the carpus in this family is the 

 relatively large size of the four carpalia {cf. p. 158). The 5th 

 carpal is represented in a ligament, the detailed relationships of which 

 have been already described (p. 154). This, as will be seen in 

 fig. 15, becomes suddenly constricted at its point of insertion into 



