170 



MAEINE EEPTILES OE THE OXFOED CLAY. 



neural arches, like the centra, are much shorter from before back than in Mvrceno- 

 saurus, and the neural spines seem never to have attained the height found in the 

 posterior cervicals of some species of that genus. The facets for the cervical ribs 

 are about as deep as long. In the anterior part of the neck they occupy nearly 

 the whole length of the centrum, but further back are separated from the anterior 

 border by a short interval. The cervical ribs are somewhat compressed from above 

 downwards, and in some individuals in which ossification is very far advanced 



Text-fig. 79. 



Anterior cervical vertebrae of Cryptocleidus oxoniensis : A and C, from front ; 

 B and D, from left side. (E. 2412, I nat. siee.) 



rt.z., anterior zygapophysis ; c.r., cervical rib ; n.c, neural canal ; 

 H.S., neural spine ; jp.z., posterior zygapopbysis, 



(e. g., E. 2862) they have a well»marked anterior angle ; this is wanting in the nearly 

 adult mounted specimen (R. 2860), in which the neural arches are fused with the 

 centra throughout the column except in the posterior caudals, while the cervical and 

 caudal ribs are free throughout. In the young skeleton (R. 2417) none of the arches 

 and ribs are fused with the centra, and the cartilage-covered surfaces for the neura 



