232 Mr. H. G. Seeley on Chelonian Remains 



the carapace, instead of nine. The costal plates are shorter 

 from front to back ; the free ends of the ribs are wider ; the 

 marginal plates appear to be wider. The whole carapace is 

 relatively much wider. 



The skull ascribed to that species, as studied from the figure, 

 pi. xi. of Prof. Owen's memoir, shows no character to differen- 

 tiate it from C. harvicensisy other than might be attributed to 

 difference in age and preservation. 



Besides the characters enumerated, both these species are 

 distinguished from the recent marine Chelonia by the forward 

 position of the first neural plate, from which it results that 

 only one pair of ribs is attached to the first costal plate, as 

 among certain Emydians. 



Of the generic distinction of Chelone harvicensis from the 

 recent marine types I have no doubt, and, from the characters 

 of the carapace and skull detailed, institute the genus Olosso- 

 chelys for its reception. 



The following notes are from additional specimens in the 

 Woodwardian Museum : — 



Glossochelys Jiarvicensis (Woodward) . 



A carapace, which may perhaps be from the young of this sj)e- 

 cies, displays the impressions left by the nuchal, first marginal, 

 neural, and eight pairs of costal plates, which are imperfectly 

 preserved at the marginal terminations. The extreme width 

 of the carapace over the third costal plate would be 11 inches ; 

 the measurement over the second to the seventh costal plates 

 is about 1\ inches ; in C. harvicensis^ t. x. A (Owen), these mea- 

 surements respectively are 15 inches in width by 12 inches in 

 length ; so that the specimen now noticed is only about two- 

 thirds as large. 



All the plates were exceedingly thin ; and the costal plates 

 were concave from front to back, and markedly convex from 

 the neural to the marginal ends. The true ribs appear to have 

 been unusually elevated on the inside of the carapace, often 

 compressed from side to side at their proximal ends, while at 

 the marginal ends they widen and appear to terminate in 

 flattened ribs | of an inch wide. In these characters they 

 differ from the type of C. harvicensis. 



The nuchal plate is concave in front ; behind it unites with 

 the first pair of costal plates by oblique sutures ; so that while 

 it is IyV inch long mesially in front of the neural plates, it is 

 only I of an inch long at the sides, where it meets the mar- 

 ginal plates. Its extreme width is about 3f inches ; its least 

 width in front is about 3 inches. 



