OCR Text |
Show 1 9 0 5 .] DINOSAUR CETIOSAURUS LEEDSI. 2 3 9 caudals of Diplodocus, only slightly less elongated. Each of these vertebrae (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 (n.a.) 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 especially 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. 7b CL Cetiosaurus leedsi.- One of the terminal caudal vertebrae, 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.] § nat. size. Text-fig. 46. Cetiosaunts leedsi.- Chevron-bones: A, from anterior caudal vertebra, anterior aspect; B, C, from middle caudals, upper aspect. The chevron-bones are remarkable as varying much in character according to their position in the tail. Only those beneath the middle caudal vertebrae numbered 15, 16, and 17 were actually found in direct contact with the centra; but there can be no doubt P r o c . Z o o l . S o c .- 1905, V o l . I. N o . X V I. 16 |