PLESIOSATTRID.E. 269 



Plesiosaurus conybeari, Sollas l . 



Syn. Plesiosaurus laticeps, Owen, MS. 2 



? Plesiosaurus latisjnnus, Van Eeneden 3 (non Owen). 



The largest species. Skull (if rightly referred) of moderate size, 

 its length being contained about three and a half times in the 

 interval between the atlas and the pectoral girdle. Neck long, 

 with 38 vertebrae. Cervical vertebrae of moderate length, with nearly 

 flat terminal faces to the centra, and the haemal surface with a low 

 and blunt ridge between small foramina ; neural spines compara- 

 tively tall, with squared summits. Anterior prolongation of coracoids 

 short, and consequently a large part of the omosternum exposed ; 

 omosternal end of ventral plate of scapula narrower than coracoidal. 

 Eadius and ulna relatively long and narrow; 6 bones in carpus 

 and tarsus. The length of the entire skeleton was probably about 

 16 feet. 



The dorsal vertebrae from the Lower Lias of Luxemburg, 

 described by Yan Beneden and identified by him with the Cre- 

 taceous Cimoliosaurus (Plesiosaurus) latisjnnus, may, from their 

 large size, be referable to the present species. 



Hob. Europe (England and [?] Luxemburg). 



R. 1338. Cast of a laterally compressed skull, apparently belonging 

 to the type specimen. The original was obtained from the 

 Lower Lias of Charmouth, Dorsetshire, and is preserved in 

 the Museum at Bristol. It is figured by Sollas in the 

 ' Quart. Journ. Geol. Soc' vol. xxxvii. pi. xxiii. fig. 1, in 

 conjunction with the type skeleton, and separately in 

 pi. xxiv. fig. 1. The evidence does not appear to be 

 absolutely decisive that this skull was found with the 

 skeleton, although such was probably the case. In length 

 and the proportions of the different parts the cranium 

 closely accords with that of P. rostratus, but the symphysis 

 of the mandible is much shorter, having a length of only 

 three inches. Purchased, 



39514. A crushed and imperfect skull, apparently resembling the 



(Fig.) preceding specimen ; probably from the Lower Lias of 



Lyme-Kegis. Described and figured by Owen in his 



' Liassic lleptilia' (Mon. Pal. Soc), Sauropterygia, p. 28, 



pi. xiii., and provisionally referred to P. rostratus. In 



1 Quart, Journ. Geol. Soc. vol. xxxvii. p. I l<» (1881). 



Davies, Geol. Mag. dec. 1, vol. iv. p. 144 1 1867).— Undefined. 

 3 Mem. Ac. R. Belg. vol. xliii. art. J 2, p. 33, pis. i.-iii. (1882). 



