PODOCNEMIS FAJUMENSIS.— STEREOGENYS CROxMERr. 
205 
C. 8790. Nearly coinpleto sliell, (lc.scril)e(l above and floured text-fig. 94. The dimeiidon.s (in 
centimetres) of this specimen are : — 
Length of cara])ace in middle lino lfi'7 
Approximate width of carajjace IdA 
Greatest length of plastron 14-4 
AVidth of anterior lobe of plastron 7’4 
Length of anterior lobe of plastron 3‘7 app. 
AVidth of posterior lobe of plastron 7‘5 
Length of posterior lobe of plastron 5'7 app. 
„ bridge 5-9 
R. 3346. Anterior portion of a mandible, probably of this species. This mandible differs from that 
of P. madagascarimsis in having a broader symphysis ; the biting surface is also much 
broader, and is partially divided into two by a median ridge. 
Genus STEREOGENYS, 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 narrower than the 
nuchal bone (in 8. lihyca) was originally regarded as a generic character, but, as 
Reinach * 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. Reinach has lately described a species of this 
genus, 8. iwdocnemioides, 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 8tereogenijs. 
Stereogenys cromeri, Andrews. 
[Plate XXV. flgs. 1-3 ; text-figs. 95, 96.] 
1901. Stereogenys cromeri, C. AV. Andi’ews, Geol. Mag. [4] vol. viii. p. 442, fig. 4. 
1903. ,, „ C. AA^. Andrews, Ann. & Mag. Nat. Hist. [7] vol. xi. p. 119, pi. viii. fig. 1. 
1903. „ „ A. von lleinacb, Abbandl. Senckenberg. naturf. Gesell. vol. xxix. pt. 1, 
p. 41. 
Tygm 8peciinen. — A skull and mandible (PI. XXV. figs. 2, 3); Geological Museum, 
Cairo. 
* Von Eeinach, “ Schildkrbteureste aus dem iigyptischen Tertiar,” Abbandl. Senckenberg. naturf. 
Gesell. vol. xxix. pt. 1 (1993) p. 34. 
