238 SATJROPTEEYGIA. 



same plate the dimensions of the centrum are : — length 

 0,051 (2-0 inches), height 0,050 (1-98 inches), width 0,065 

 (2*55 inches) ; which agree very closely with those of the 

 type. In the caudal, which is figured by Seeley, op. cit. 

 figs. 4, 5, the length is 0,038 (1-5 inches), height 0,039 

 (1-55 inches), and width 0,054 (2*1 inches) ; the anchylosed 

 chevrons are broken off. The length of the associated 

 humerus is 0,253 (10 inches). In another adult skeleton 

 in the same collection (No. 22) the length of the humerus 

 is 0,290 (11-45 inches). The later cervical vertebrse of 

 the latter skeleton agree precisely with the types. 



Made in the Museum, 1888. 



It. 1282. Casts of the centra of an anterior and a posterior cervical 

 vertebra of an immature individual. The originals belong 

 to a skeleton (No. 23) from the Oxford Clay of Peter- 

 borough in the collection of A. N. Leeds, Esq. The 

 dimensions of the smaller specimen are : — length 0,043 

 (1-7 inches), height 0,035 (1-37 inches), width 0,042 (1-65 

 inches) ; those of the larger being : — length 0,053 (2-1 

 inches), height 0,042 (1-65 inches), width 0,062 (2-44 

 inches). The length of the associated humerus is 0,271 

 (10- 7 inches). Allowing for the difference of age and serial 

 position the dimensions of the larger vertebra accord well 

 with those of the types. The immature cervicals on which 

 Plesiosaurus infraplanus was founded precisely resemble 

 those of the present skeleton ; the dimensions of the speci- 

 men from Brill are : — length 0,045 (1*79 inches), height 

 0,046 (1*82 inches), and width 0,052 (2-03 inches). 



Same history. 



48002. A very early cervical vertebra ; from the Oxford Clay near 

 Oxford. Length 0,029 (1-14 inches), height 0,025 (0-95 

 inch), width 0,030 (1-2 inches). 



Presented by the Hon. JR. Marsham, 1877. 



44187. The associated centra of four immature cervical vertebras ; 

 from the Oxford Clay of Weymouth, Dorsetshire. 



Purchased, 1873. 



48001. The centrum of a small and malformed cervical vertebra; 

 from the Oxford Clay near Oxford. This specimen is 

 immature ; and on one side is divided into two portions, 

 each with its distinct costal facet. 



Presented by the Hon. R. Marsham, 1877 



