174 



PROF. G. B. HOWES AND ^\ . RIDEWOOD ON [Mar. 6, 



family, and with the exception of a hroadening of the pollex in 

 Cornufer and Rltacophorus, and an increase in size of the proximal 

 end of tlie pre-hallux metatarsal segment in the first-named genus, 

 we have met with no important departure from what is seen in the 

 Common Frog. As this animal is so largely in demand for ordinary 

 class use\ we append a somewhat detailed description of its Hmb- 

 skeletou, in the light of our preceding ohservations. 



Fig. B. 



Bana tcmporaria, J, 54 mm. in length. 



Left, fore foot, dorsal view, x 12. Tlie coalesced radius and ulna (r. u) are 

 represented in tbe natural position. For references see p. 182. 



Fore Foot (Rana temporaria). 



In the adult carpus of this animal, six bones may be recognized, 

 all of which are in their original positions with the exception of the 

 naviculare (?«). This has, as already remarked (p. 158), undergone 

 elongation and displacement radially. We were not a little sur- 

 prised to find that there is considerable variation in the position of 

 this element in young Frogs, whose carpus and tarsus were still 

 unossified. In a large series of specimens examined, measuring at 



^ The descriptions given in the students' manuals (Huxley & Martin's 

 ' Elera. Biology,' Marshall's ' Frog,' and Mivart's ' Common Frog ') are ibr the 

 juost part compilations, and we deem it unnecessary to criticise them in detail. 



