SKELETON OF THE WILD DUCK. THE SACRUM. 311 



and have been already described with the other thoracic 

 vertebrae. Their neural spines and, those of the four succeed- 

 ing vertebrae are fused together, forming a continuous crest 

 of bone completely united laterally with the ilia. The trans- 

 verse processes of all these six vertebrae are well developed, 



A B 



FlG. 58. A, DORSAL AND B, VENTRAL VIEW OF THE PELVIS AND SACRUM OF 



A DUCK (Anas boschas). 



1. ilium. 4. pectineal process. 



2. ischium. 5. lumbar vertebrae. 



3. pubis. 6. true sacral vertebrae. 



but those of the posterior two (fig. 58, B, 5) are much the 

 stoutest. The next three vertebrae have broad centra, but 

 their transverse processes are very slightly developed and have 

 no ventral elements. These seven vertebrae belong to the 

 lumbar series. The remaining eight vertebrae have well- 

 developed transverse processes, which in the case of the first 

 three or four are divisible into dorsal and ventral elements. 

 All the dorsal elements are united to form a pair of flattened 

 plates, partially separated by a series of foramina from a 



