360 GeoiyiiKt Siveft : 



neural ai-ch is wanting — and correspondingly the left exocci- 

 pital has no condyle, the vertebral column being simply very 

 closely connected with the skull on the left^ — so closely that it 

 is only after careful examination that one is sure that it is 

 not fused. The bodies of the 2nd, 3rd, Ith and 5th vertebrae 

 are completely fused, and somewhat distorted. This ventral 

 fused mass is procoelous, and convex behind. The bodies of 

 the 2nd, 3rd and 4th vertebrae are incomplete on the left side 

 (see PI. XX., Fig. 8b). The neural arches of the 2nd and 3rd, and 

 of the ith and 5th. are fused in a peculiar distorted way, which 

 may be readily seen on reference to PI. xx.. Fig. 8a. The trans- 

 verse processes, which are slightly broken, appear to have been 

 nearly normal on the right side. On the left, however, those 

 belonging to the 2nd and 3rd vertebrae are absent, the space left 

 in this way and by the incomplete centra forming a long oval 

 opening through which, presumably, the 2nd, 3rd, Ith and 5th 

 spinal nerves left the spinal column on the left side. The 

 transverse processes of the Ith and 5th vertebrae on this left 

 side arise from the region of the anterior part of the 5th neural 

 arch by a broad common base, which soon splits into 2, one 

 turning outwards and forwards, the other running outwards 

 and very slightly backwards. The transverse processes of the 

 6th and 9th are ap^jreciably larger on the left than on the right. 

 The general relations of the vertebrae will be seen clearly on 

 reference to the Plate xx.. Figs. 8a and 8b. The rareness of such 

 variations in HyJa aurea may be guessed from the fact that 

 the variations herein recorded have been gathered fimn over 

 two thousand frogs. 



Fusion of vertebrae is not unknowii in the Anura, though I am 

 not aware of its having been previously recorded in Ih/la. In 

 addition to the cases in Pi pa and Xenopus, tigured by Kidewood 

 (1897), the following are the chief records available to me: — 

 1-1-2 Felobates fuscus, syminetrical. Adolphi, '95, tigs. 2, 3 



,, liana mugiens, not ,, Benliam,'94,tigs. 1,3,4,6 



1 -I- 2 4- 3, Felobates fuscus ,, ,, .Vdolphi, '95, tig. 5 



2-4-3 iUifo cinereus, ,, „ "98, tig. 1 



3+4 „ „ „ „ . 2 



,, Kaiia mugiens, not ,, Benhani, '94, tigs. 1, 2 



3-f4 + 5, „ „ „ „ „ '94;tigs.7,8,9,10 



