NO. 1GG(5. 



OSTEOLOGY OF CAMl'TOSAURUS—GILAIORE. 



287 



last cervical to the side of the neurapophyses in the early dorsals, 

 and finally to the anterior border of the transverse process in the 

 median dorsal region, approximates the conditions noted in the 

 American species. The presence of 18 dorsals with this specimen 

 raises the question as to the correctness of the vertebral formula of 

 Camptosaurus, as determined from a study of the two skeletons. Cat. 

 Nos. 4282 and 2210, U.S.X.M., which agree in having 10 vertebra?, 

 considered as dorsals, in front of the sacrum. If 10 is the correct 

 number for Camptosaurus, then C. presttvichii, having 18 dorso-lum- 



1 



bars, api^roaches Iguano- 

 don more closely. 



In the sacrum, five verte- 

 bra^ are united by suture, 

 the most anterior of which 

 is considered by Ilulke as 

 a lumbar (sacro-dorsal), 

 the posterior four being 

 true sacrals (see fig. 43). 

 "\Aliile the sacrals do not 

 show the well-defined jDeg- 

 and-notch articulation of 

 some of the American 

 species, yet, as shown by 

 the figures of this region, 

 there appears to be a tend- 

 ency toward the develop- 

 ment of such an articula- 

 tion between sacrals one 

 and two, and also between 

 sacrals two and three, 

 much as in C. nanus. In 

 the size and number (five) 

 of coossified vertebra? and 

 the contour of their ven- 

 tral surfaces, the sacrum 

 approaches that of C. 

 nanus. It differs, how- 

 ever, in the transversely 

 contracted neural canal of the fourth which also bears the transverse 

 process or last sacral rib wholly upon its centrum. As will be seen 

 in fig. 39, this rib is borne intervertebrally in C. nanus. In the trans- 

 verse contraction of the neural canal of C. prestwichii, the fourth 

 sacral resembles that of C. dispar, as shown in fig. 37, although, as 

 in C. names, the rib is supported intervertebrally. 



Fig. 43. — (1) The last doesal or saceo-dorsal and 



SACELT.M OF CaMPTOSAURUS PRESTWICHII (Lr- 



DEKKER), Museum of Oxford. Holotype. Seen 



FROM below. J NAT. SIZE. (2) THE SAME FROM 

 ABOVE ; U, SACRO-DORSAL ; 1. S., 2. S.j 3. S., AND -}. S., 

 SACRALS ONE TO FOUR, EESPECTIVELY ; ng, NERVE- 

 GROOVE. After Hulke. 



