1905.] 



DINOSAUR CETIOSAURUS LEEDSI. 



239 



caudals of Diplodocus, only slightly less elongated. Each of these 

 vertebras (text-fig. 45) consists of a long constricted centrum with 

 strongly convex, almost conical ends ; and it bears on the middle 

 of its upper face only a rudiment of a neural arch in the form of 

 a pair of elongated ridges (?«-.«.) which exhibit a facette for a 

 capping of cartilage above. A chain of such vertebrae at the end 

 of so massive an animal as Cetiosaurus must have been esjDecially 

 liable to accident ; and it is interesting to note that the short 

 series discovered by Mr, Leeds has been broken at two points and 

 repaired during the life of its original possessor. 



Text-fig. 45. 

 no, 



Cetiosaurus leedsi. — One of the terminal caudal vertebra, left lateral aspect. 

 n.a., surface for cartilaginous upper part of neural arch at summit of ossified 

 lamina or pedicle. [Brit. Mus. no. R. 1967.] f nat. size. 



Text-fig. 46. 



Cetiosaurus leedsi. — Chevron-bones : A, from anterior caudal vertebra, anterior 

 aspect ; B, C, from middle caudals, upper aspect. 



The chevron-bones are remarkable as vaiying much in character 

 according to their position in the tail. Only those beneath the 

 middle caudal vertebrse numbered 15, 16, and 17 were actually 

 found in direct contact with the centra ; but there can be no doubt 



Proc. Zool. Soc— 1905, Yol. I. No. XYI. 16 



