Dr. C. W. Andrews — Extinct Egyptian Vertebrates. 441 



prominent and rises farther above the head (b), and the form of 

 the proximal portion of the radial process (c) is different in several 

 respects. For the present, until further remains are collected, it 

 will be best to refer this form to Psephophorus. The specific name 

 will be P. eocanus. 



Dimensions of Humerus. 



Total length 190 mm. 



"Width of shaft immediately below radial process ... 42 ,, 

 Width of head 40 „ 



Thalassochelys libyca, sp. nov. 



Another Chelonian, represented in the collection by several more 

 or less crushed skulls, is a Cryptodiran with roofed temporal fossas, 

 apparently closely allied to Chelone. In two cases the skulls are 

 greatly crushed from above downward, giving them a quite mis- 

 leading appearance of being low and flattened, but another specimen, 

 including the back of the skull as far forward as the epipterygoid 

 (columella), is quite uncrushed, and is here referred to. 



Fig. 3. — Dorsal and ventral views of left humerus of Fsephophorus eoccenus, 

 Andrews. One-fifth natural size, (a) Ulnar crest; (J) head; (c) radial crest ; 

 {d) entocondyle. 



The form of the tympanic ring, which is incomplete posteriorly, 

 resembles that seen in Chelone, showing that this species is not 

 a Pleurodiran. The presence of the columella shows that it is not 

 one of the Athecate group, as from the occurrence of the humerus 

 above described seemed not impossible. The roofing of the temporal 

 fossa, as far as can be seen, is the same as in the Chelonidse, and it 

 may be referred provisionally to that family. The occipital condyle 

 is trilobate, the basi-occipital extending up to the foramen magnum. 

 The basi-sphenoidal platform is much less prominent than in Chelone, 

 and there is no deep fossa beneath its hinder border as in that genus. 



