SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 



Fourth Cervical 



Lipotes 



General outline about as wide as 

 high. 



Transverse processes united, not 

 very different from those of third 

 cervical, but more slender. 



Inia 



General outline higher than wide. 



Transverse processes separate, con- 

 spicuously different from those of 

 third cervical, the lower greatly 

 broadened and curved forward under 

 transverse process of third cervical. 



Fifth Cervical 



Transverse processes separate, the 

 lower with a distinct projection indi- 

 cating the outline of the lateral canal ; 

 extremity of lower process thickened 

 and curved forward under transverse 

 process of fourth cervical. 



Transverse processes separate, the 

 outline of the canal not indicated ; 

 lower process enlarged, straight, the 

 extremity much thickened. 



Sixth Cervical 



No definite neural spine. 



Lower transverse process with 

 small projection indicating boundary 

 of lateral canal ; extremity of lower 

 process greatly expanded into an 

 oblique, plate-like mass which extends 

 slightly beyond level of anterior face 

 of centrum and decidedly beyond 

 level of posterior face as well as 

 beyond level of lower border. 



A small neural spine. 



No indication of boundary of canal ; 

 lower transverse process small, not 

 extending beyond level of anterior 

 and posterior faces of centrum or 

 below level of its lower border. 



Seventh Cervical 



Neural spine slightly developed, its 

 height less than half that of neural 

 canal. 



Transverse processes united, com- 

 pletely closing the lateral canal. 



Neural spine greatly developed, its 

 height about twice that of neuraL 

 canal. 



Upper transverse process alone 

 present, the position of the bas,e of 

 lower process indicated by a faint 

 thickening on edge of centrum. 



Teeth. — The teeth are probably more numerous than is usual in 

 Inia, they are smaller relatively to the width of the palate, and they 

 project more at the sides of both beak and lov^^er jaw. These general 

 peculiarities are well shown by the plates. The form of the exposed 

 portion of all the teeth is essentially like that of the median teeth 

 in the South American animal. The rugosity of the enamel is nearly 

 as evident as in Inia, it dififers from that of Inia in a structure which 

 may perhaps be best described as more reticulate and less nodular. 



