212 SAUROPTEKYGIA. 



"pectorals" figured by Leidy, and also those of C. constrictus, 

 have elliptical faces, while in the posterior dorsals of the 

 latter these faces are subcircular. The dimensions of the 

 centrum are :— length 0,077 (3*02 inches), height 0,093 

 (3-65 inches), width 0,113 (4*44 inches). The specimen 

 agrees closely in size with the type vertebrae figured by 

 Leidy in his ' Cretaceous Eeptilia of the United States ' 

 (Smiths. Contrib. Knowl. 1864), pis. v., vi. ; and apparently 

 closely resembles the specimen represented in pi. v. fig. 16 

 as an anterior dorsal. The general contour of the specimen 

 agrees so closely with that of the dorsals of C. constrictus 

 and C. haasti, as to leave no doubt of the generic identity 

 of the three forms. There is a somewhat prominent ridge 

 on the haemal aspect, between two large foramina. The 

 neural spine and ribs are wanting. 



Presented by Sir C. Lyell, Bart., 1859. 



Cimoliosaurus constrictus (Owen 1 ). 

 Syn. Plesiosaurus constrictus, Owen a . 



Elasmosaurus constrictus, Cope 3 . 

 Including : — 



Mauisaurus gardneri, Seeley 4 . 

 Plesiosaurus gardneri, Whidborne 5 . 

 Plesiosaurus helmerseni, Kiprijanoff 6 . 

 Pliosaurus (?) gig as, Schroder 7 . 



Of gigantic size, with the neck of enormous length. Cervical 

 vertebras about 35 in number; those of the anterior region with 

 their centra greatly elongated, laterally constricted, flattened and 

 carinated on the haemal surface, and the extremities much expanded, 

 with their terminal faces very wide and slightly cupped ; posterior 

 cervicals much shorter, their length being absolutely less than that 

 of the middle cervicals, and their terminal faces nearly flat ; dorsals 

 with the terminal faces of the centra flat and nearly circular. 

 Humerus (judging from the specimen figured by Kiprijanoff, op. 

 cit. pi. xiv.) of medium size, with moderately wide distal expansion, 



1 In Dixon's ' Geology of Sussex,' 1st ed. p. 398 (1850). — Plesiosaurus. 



2 Loc. cit. 



3 Trans. Amer. Phil. Soc. vol. xiv. pt. i. — Advance separate copy, p. 42 

 (1869). Omitted in subsequent issue (1870). 



4 Quart. Journ. Geol. Soc. vol. xxxiii. p. 541 (1877). 

 8 Ibid. vol. xxxvii. table facing p. 480 (1881). 



6 Mem. Ac. Imp. St. Petersbourg, vol. xxx. art. 6, p. 17 (1882). 



7 Jahrb. preuss. geol. Landesanstalt for 1884, p. 322 (1885). 



