212 PALEONTOLOGY 



to be reckoned therefore as dorsal vertebrae. In the cervical 

 vertebra? the rib-pit is large, vertically reniform, not divided 

 by a groove ; its circumference slightly projects in Kotho- 

 sawrus. 



There is no clear evidence of any of the cervical ribs being 

 terminally expanded and hatchet-shaped, as in Plesiosaurus ; 

 those of the back are vertically longer than in Plcsiosanrvs, 

 and more convex. 



In the sacral vertebrae, fourth in fig. 69, the rib-pits again 

 begin to sink upon the centrum. 



There are two distinct sacral vertebra; in Nothosaitrus. 

 They are known by their long, straight, terminally-bent, and 

 convergent pleurapophyses, the first of which overlaps a little 

 the second. To the convergent ends of these riblets, the ilium 

 (fig. 69, 62, pi) was doubtless ligamentously affixed. In the 

 first caudal vertebra the par- and di-apophyses stand out much 

 farther than in the sacrum ; but rapidly shorten in the second 

 and third caudals. The compound process in each supports a 

 short stiliform straight riblet, as in the fifth figured vertebra 

 (fig. 69) ; the anterior and succeeding caudals support ha?mal 

 arches and spines, after the disappearance of the pleur- 

 apophyses. The haemal arch disappears in about the eighth 

 vertebra from the end, and finally the neural arch. The 

 terminal centrums are subelongate and subcompressed. Both 

 Nothosaurus and Pistosaurus had abdominal ribs, of which the 

 median piece (fig. 69, hs) was subsymmetrical, the two rays 

 diverging at a very open angle, and terminating in a point or 

 a fork ; the side-pieces (?>) seem not to have been so numerous 

 as in Plcsiosmirus. 



The scapula (fig. 69, 51) is a short and strong bone, its 

 blade appearing as a short and narrow sub-compressed process 

 extending from the subquadrate, thick and expanded end 

 which affords the articular surfaces for the coracoid, clavicle, 

 and humerus. 



