1078 



CLASS REPTILIA. 



pletely closing the scapulo-coracoidal foramen. 1 The humerus (fig. 

 998) is usually longer than the femur ; and both these elements may 

 articulate distally with either two or three (figs. 998, 999, 1000) 

 bones, which in the later instances lose all resemblance to the nor- 

 mal elongated form. The ischia are relatively short. 



This genus may be divided into two groups, according to whether the 

 vertebral centra have nearly flat or deeply cupped centra. In the former 

 group we have the large C. truncatus of the Kimeridge, and the smaller 

 C.plicatus (fig. 1000 bis) and C. Richardsoni '(fig. 1000) of the Oxford Clay, 

 in both of which the humerus articulates only with the radius and ulna ; 

 the latter species being distinguished by its shorter cervical vertebrae. 



Fig. 999. — Ventral aspect of part of the right pelvic limb 

 of Cimoliosaurus portlandicus ', from the Portland Oolite. 

 Reduced. T, Preaxial ; F, Postaxial border ; 66, Tibia ; 

 67, Fibula ; 67', Homologue of the pisiform ; /, Tibiale ; 

 ci, Intermedium; c 2, Fibulare ; /, Postaxial tarsal. 

 (After Hulke.) 



Fig. 1000. —Ventral as- 

 pect of part of the right 

 pectoral limb of Cimolio- 

 saurus Richardsoni I from 

 the Oxford Clay. One- 

 eighth natural size. h, 

 Humerus : tr, Trochanter 

 of do. ; r, Radius ; u, Ulna ; 

 r\ Radiale ; 2, Interme- 

 dium ; u', Ulnare. (After 

 Mansel-Pleydell.) 



In C. portlandicus, of the Portland Oolite ana Purbeck, there were 

 three short bones articulating with the humerus and femur (fig. 999). It 

 is in the Cretaceous, however, that we meet with the largest representa- 

 tives of this group, which comprise C. co?istrictus, of the European Gault 

 and Chalk ; C. vetustus and C. ftlatyurus, of the Cretaceous of North 

 America ; and C. Haasti, in the corresponding strata of New Zealand. 

 These were enormous reptiles, with an estimated length of between 30 



1 Occasionally, as in C. durobrivensis, of the Oxford Clay, this bar may be 

 absent, but it is not known whether this is only an individual peculiarity. 



