274 TEETIAET VEETEBEATA 01" THE FATtTM. 



Tomistoma kerunense, Andrews. 



1905. Tomistoma kerunense, C. W. Andrews, Geol. Mag. [5] vol. ii. p. 484. 



Ti/pe Specimen. — An imperfect rostrum, the premaxillary region being lost; 

 Geological Museum, Cairo. 



This species diifers from T. gavialoides in having a more gradually tapering snout 

 and less rounded orbits. The teeth are more nearly equal in size, larger, and set at 

 wider intervals than in other species of the genus. 



Form. & Log. — Birket-el-Qurun beds (Middle Eocene) : 12 kilometres W.S.W. of 

 Gar-el-Gehannem. 



It is unfortunate that this species is very imperfectly known, since its remains 

 occur in the beds below those at Qasr-el-Sagha in which T. africanum, is found, and 

 better specimens might have thrown some light on the succession of forms from this 

 horizon to the Upper Eocene species Tomistoma gavialoides. The snout, which is the 

 best specimen available for description, is much like that of T. gavialoides in general 

 form. Immediately in front of the orbits its surface is curved regularly from side to 

 side, much as in T. schlegeli, but it is somewhat more depressed, a condition which 

 is continued throughout the length of the rostrum. The tapering of the preorbital 

 region is quite gradual, more so than in T. gavialoides (see PI. XXIII. fig. 3 a) ; 

 the orbits are less rounded than in that species, though less elongated than in 

 T. schlegeli. The specimen shows that the nasals meet the premaxillae in the manner 

 characteristic of the genus, thus excluding the maxillse from union in the middle 

 line on the upper surface of the snout. The interorbital bar is broader than in 

 T. gavialoides. 



The teeth, judging from the alveoli, were large and were directed more forwards 

 and outwards than in T. schlegeli, from which this form is also distinguished by the 

 absence of pits for the reception of the tips of mandibular teeth. The teeth seem to 

 have been more nearly equal throughout the series than in T. schlegeli or T. africanum, 

 and are separated by wider intervals, so that between the level of the posterior end 

 of the palatine processes of the premaxillae and the anterior angle of the posterior 

 palatine fossa there are only nine teeth, while in T. schlegeli, in the same space, there 

 are ten, and in T. gavialoides twelve. 



A portion of the back of a skull, including the occipital surface and the roof as far 

 as just in front of the supratemporal fossae, was also collected by Mr. Beadnell in the 

 same locality. So far as it is preserved, this part of the skull is almost identical with 

 that of T. gavialoides. 



