CHELONIDJE. 47 



Argillochelys subcristata (Owen 1 ). 



Syn. Chelate subcristata, Owen 2 . 



Puppigerus subcristatus, Cope 3 . 

 (?) Chelone subcarinata, Bell 4 . 

 (?) Puppigerus subcarinatus, Cope \ 



Neural bones of carapace with the antero-lateral facets much 

 shorter than the postero-lateral ones. Carapace depressed, with the 

 neurals elongated, and in some instances carinated posteriorly ; and 

 the vertebral shields comparatively narrow. Plastral vacuities 

 large. 



It appears most probable that the characters on which Chelone 

 subcarinata was separated from the present form are not of more 

 than individual value, and the type of the former is accordingly 

 included under the present specific heading. 



Hab. Europe (England). 



38952. The shell, wanting nearly all the marginals, and otherwise 

 (Fig.) imperfect ; from the London Clay. The type ; figured by 

 Owen in his ' Reptilia of the London Clay, &c.' vol. i. 

 pt. i. pi. viii. The convexity of the middle antero- 

 posterior line of the carapace has been broken down by 

 pressure. The plastron is not well preserved ; but the 

 long slender xiphiplastrals are clearly shown, and the 

 contour of the entoplastral can also be distinguished. 

 Some of the bones of the limb-girdles and limbs remain. 

 Bowerbank Collection. Purchased, 1865. 



39762. The shell, wanting the marginals, but otherwise nearly 

 (Fig.) entire ; from the London Clay (Lower Eocene) of the Isle 

 of Sheppey. The type of C. subcarinata. Eigured by 

 Bell in the ' Beptilia of the London Clay, &c.' vol. i. pt. i. 

 pi. viii. a. The contour of the epi- and entoplastrals is 

 almost exactly the same as in Thalassoclielys ; the xiphi- 

 plastrals have been somewhat crushed together by pressure. 

 The humerus of either side is preserved, but in a somewhat 

 imperfect condition, so that the characters of the proximal 

 extremity cannot be determined ; the shaft is, however, 

 much constricted. Bowerbank Collection. 



' Eep. Brit. Assoc, for 1841, p. 179 (1842).— Chelone. 2 Loc. tit. 



3 Trans. Amer. Phil. Soc. vol. xiv. pt. i. p. 235 (1870) (Mon. Pal. Soc). 

 i Owen & BeU, Eeptilia of the London Clay, vol. i. &c pt. i. p. 37 (1849). 

 5 Loc. cit. 



