SPINAL NERVES OF THE FROG. 125 



Fig. 3. Same dissection of a R. esculenta; 6 + , an extra 

 vertebra ; vi. + , its corresponding nerve ; Tr. 

 P., transverse processes of the compound 

 sacrum (vertebrae 8 and 9) ; //., ilium. Other 

 letters as before. X 2. 



Fig. 4. Dorsal and ventral views of the compound sacrum 

 of the third specimen (cf. fig. 3). A. ventral 

 view ; B. dorsal view. A. zy., anterior zyga- 

 pophysis ; .C, centrum ; F., fissure imperfectly 

 separating the neural arch of the sacrum into 

 two; 1. F., intervertebral foramina trans- 

 mitting the viiith nerve; II., Ilium; -N.S., 

 neural spine ; Ur., urostyle ; 8 and 9, trans- 

 verse processes of the compound sacrum. X 3. 



