PLESIOSArRID^. 



241 



R. 1263. Casts of an associated imperfect middle (?) cervical 

 and anterior caudal vertebrae. The originals belong to 

 a nearly entire skeleton obtained from the Oxford Clay 

 of Weymouth, Dorsetshire, in the possession of Nelson 

 "Richardson, Esq., of Montevideo, near Weymouth, which 

 is the type of the species, and is noticed by Mansel-Pleydell 

 in the ' Proc. Dorset. Nat. Hist. Club/ vol. ix. table facing 

 p. 40 (1888), under the name of Plesiosaurus plicatus. 

 The cervical vertebra (fig. 73) has lost the summit of the 

 neural spine and the extremities of the ribs, and the 

 centrum has its terminal faces somewhat expanded through 

 pressure. The dimensions of the centrum are : — length 

 0,041 (1*57 inches), height 0,050 (1-95 inches), width 

 0,062 (2-45 inches). The relative length of the centrum 

 is much less than in any of the cervicals of the above 



Fig. 73. 



Cimoliosavrvs richardtovi. — Anterior and left lateral aspects of a cervical 

 vertebra; from the Oxford Clay of Weymouth. \. co, rib; pr.z, pro-, 

 pt.z, postzygapophysis. 



mentioned skeletons of C. 2^iccitvs ; and the complexity 

 of the zygosphenal articulation so characteristic of this 

 group is well shown. The caudal has been somewhat 

 distorted by pressure ; it shows the nearly entire chevrons 

 anchylosed to the centrum. It is somewhat larger and 

 relatively shorter than the caudal of C. plicatus, No. 

 11. 1262 (p. 237), but has the same general structure. 

 The restored pectoral girdle associated with these ver- 

 tebra is shown in fig. 74. Made in the Musi "///, 1888. 



PART II. R 



