1893.] TEETEBEAL A]ST) LlilB-SKELETOlT OP THE AMPHIBIA. 



269 



vertebrae on the right side. On searching through an accumulation 

 of Frogs' bones in my possession, I found a specimen (fig. 2 b) 

 which, except for certain subtle and altogether unimportant 

 differences of an adaptive nature, closely parallels Adolphi's Toad ; 

 and I am indebted to my demonstrator, Mr. M. F. Woodward, 

 for a backbone in which the opposite (left) side, instead of the 



fTr'VTtt 



a-, via 



tr.IK. 



Vertebral column of Rana esciilenta. 



Fig. 1 a. The Tertebral column of an individual in which the List two vortebrte 

 had completely united, ventral aspect. Fig. 1 b. The united 8th and Dth 

 Tertebra3 of the same, dorsal aspect. Fig. 1 c. The same, lateral aspect. 

 Fig. 2 a. The correspondingly united 8th and 9th vertebra; of another 

 individual, having a compound sacrum on the left side. Fig. 2i. A 

 similar case to 2 a, but with the compound sacrum on the opposite 

 side. 2 a and 2 6, dorsal aspect. All 1^ nat. size. • 



/, furrow, denoting the point of fusion of adjacent parts ; i.v, inter- 

 vertebral foramen ; tr, transverse process ; x, eminence at the point of 

 fusion of adjacent vertebral bodies. 



right, was similarly modified (fig. 2 a). In his specimen the 9th trans- 

 verse process furnished the sacral articulation on the non-affected 

 side, as with Adolphi's Toad ; while in my own (fig. 2 h) the eighth 

 ftdfilled that function. 



Except for a relative diminution in the length of its urostyle, 

 and for the fusion of parts already referred to, the Frog's backbone 

 first described (fig. 1 «) was in no respect structurally abnormal. 

 Its anterior three vertebrae were, however, far less freely movable 

 than is normally the case ; and in this they anticipate as it were the 

 greater fusion of these bodies so frequently met viith in Ceratophrys 



Peoc. Zool. Soc— 1893, No. XIX. 19 



