PODOCNEMIS FAJIJMENSIS.— STEEEOGENTS CEOMEEI, 295 



C. 8790. Nearly complete shell, described above and figured text-fig. 94. The dimensions (in 

 centimetres) o£ this specimen are : — 



Length of carapace in middle line 16'7 



Approximate width of carapace 13-4 



G-reatest length of plastron 14-4 



"Width of anterior lobe of plastron 7'4 



Length of anterior lobe of plastron 3-7 app. 



Width of posterior lobe of plastron 7*5 



Length of posterior lobe of plastron 5-7 app. 



„ bridge 6-9 



R. 3346. Anterior portion of a mandible, probably of this species. This mandible differs from that 

 of P. madagascariensis in having a broader symphysis ; the biting surface is also much 

 broader, and is partially divided into two by a median ridge. 



Genus STEEEOGENYS, Andrews. 

 [Geol. Mag. [4] vol. viii. (1901) p. 442.] 



This genus is nearly allied to Podocnemis, but is distinguished from it by : (1) the 

 great length and massiveness of the mandibular symphysis ; (2) the posterior position 

 of the internal nares resulting from the approximation of the palatines in the middle 

 line to form a floor to the narial passage ; (3) the large size of the intergular shield, 

 which separates the gular and humerals ; (4) the slight development of the axillary and 

 inguinal buttresses. The fact that the anterior vertebral shield is narrovs^er than the 

 nuchal bone (in S. Uhyca) v?as originally regarded as a generic character, but, as 

 Eeinach * has pointed out, it is doubtful whether this character occurs in all the 

 species; the same is the case with the separation of the neural bones from the nuchal 

 in front and the suprapygal behind. Eeinach has lately described a species of this 

 genus, 8. fodocnemioides, from the Middle Eocene of the Fayum, which in several 

 respects, e. g. the relations of the intergular shield to the humerals, is intermediate in 

 structure between the typical members of the genera Podocnemis and Stereogenys. 



Stereogenys cromerij Andrews. 



[Plate XXV. figs. 1-3 ; text-figs. 95, 96.J 



1901. Stereogenys cromeri, C. W. Andrews, Geol. Mag. [4] vol. viii. p. 442, fig. 4. 

 1903. „ „ 0. W. Andrews, Ann. & Mag. Nat. Hist. [7] vol. xi. p. 119, pi. viii. fig. 1. 



1903. „ „ A. von Eeinach, Abhandl. Senckenberg. naturf. Gesell. vol. xxix. pt. 1, 



p. 41. 



Tyjte Specimen. — A skull and mandible (PI. XXV. figs. 2, 3) ; Geological Museum, 

 Cairo. 



* Von Eeinach, " Schildkrotenreste aus dem agyptischen Tertiar," Abhandl. Senckenberg. naturf. 

 GeseU. vol. xxix. pt. 1 (1903) p. 34. 



