174 



I'ROF. G. B. HOWES AND \V. RIDEWOOD ON [Mar. 6, 



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

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

 end of the 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 limb- 

 skeleton, in the light of our preceding ohservations. 



Fig. B. 



Bana tcwfporaria, J, 54 mm. hi length. 



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

 represented in the natural position. Por references see p. 182. 



Fore Foot (Rana temporaria). 



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

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

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

 elongation and disjdacement 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 Fi-og ') are for the 

 most part compilations, and we deem it unnecessary to criticise tbeiu in detail. 



