DERMOCHELIIDiE. 223 



38652. A dorsal vertebra, with parts of the overlying region of the 

 {Fig.) carapace in an imperfect condition. Described and figured 



by Meyer, op. cit. p. 123, pi. xxix. figs. 8-10. 



38653 x. The eighth costal bone of the left side. Traces of sulci are 



visible. 

 38653 y. A marginal bone, apparently from the posterior region of 



the carapace. 



38653. A number of undetermined and fragmentary bones. 



28877. Tho imperfect right humerus or femur of a Chelonian perhaps 

 referable to this or an allied form ; from the Upper Trias 

 of Linksfield, near Elgin. Noticed by Owen in the ' Rep. 

 Brit. Assoc' for 1841, p. 168 ; and figured by Duff in 

 his ' Geology of Moray,' pi. v. fig. 10 (1842). The head 

 is wanting, and there is no distal groove or foramen. The 

 specimen differs very markedly from the corresponding 

 bone of any existing type. Purchased, 1854. 



Suborder II. ATHECATAK 



Carapace composed solely of dermal ossifications, which are totally 

 unconnected with the vertebras and ribs. Skull typically 2 without 

 vertical descending plates from the parietals ; and the opisthotic 

 separated from the squamosal by the quadrate. 



Family DERMOCHELYID^] 3 . 



Carapace composed either of a median row of large and broad 

 scutes and lateral marginal rows, or of a mosaic of small irregular 

 scutes or tesserae, traversed by longitudinal rows of larger ones ; 

 plastron equally variable. Skull with the temporal fossee completely 

 roofed, the squamosal joining the parietal; tympanic ring open 

 ponteriorly ; no bony floor to the narial passage ; and no enlarged 

 alveolar surface to the trenchant jaws. Humerus (fig. 51) flattened, 

 with a large radial process placed near the middle of the shaft, a 

 very large ectepicondylar foramen, and the head imperfectly defined 

 and situated in the same plane as the ulnar process. 



1 Amended from Athecas, Cope. 



2 Baur (Biol. Centralblatt, vol. ix. p. 190, 1889) states that in a skull referred 

 to Protostega the parietals are connected by descending plates and epiptery- 

 goids with the pterygoids. 



3 Equal Sphargidce. The relegation of the name Sphargis to the rank of 

 a synonym in favour of Dermochelys renders the above name the proper one 

 for the family. The retention of the name Dermochelys, instead of the later 

 Dcrmatochelys, may be justified by Aristotle's SepixoTrrepos. There is also a 

 precedent in Megatherium in lieu of Megalotherium. 



