128 TEETIAET YEETEBRATA OF THE EATtTM. 



concave at botli ends. The transverse processes of all except the seventh are perforated 

 by a vertebrarterial canal, and on the anterior ones there is a strong hypapophysial 

 ridge on the hinder end of the centrum. 



The anterior dorsal has an oval biconcave centrum ; the external angles of the 

 posterior face bear concave facets for the capitulum of the rib ; the transverse process 

 is stout and short and bears a large down wardlj"-- directed tubercular facet, strongly 

 concave from before backwards. The other dorsal centra have a straight neural border 

 and are strongly convex below. The lumbar centra are similar, and bear on their 

 sides strong flattened transverse processes. 



Height of Width of Length of 



anterior face. cfitto. centrum. 



Atlas 7'5 65 (with odontoid). 



Last cervical 3'3 3'5 2-6 



Anterior dorsal 3-3 3-8 2-8 



Posterior dorsal .... . 3'8 5-5 app. 3-8 



Lumbar SB 4-7 3-8 



M. 8191. Plaster cast of palatal region of type skull. Made in the British Museum. 



M. 8912. Left upper molars. Figured on PL XVII. fig. 3. These teeth show the well-developed 

 cingulum and the peculiar sculpturing of the enamel. The dimensions (in centimetres) 

 are : — 



Length. "Width. 



m. 1 2-5 2-1 



m.2 2-7 2-3 



m. 3 2-8 2-5 



Presented by the Egyptian Government, 1904. 

 M. 9229. Centrum of axis with odontoid. Presented by Baron Franz Nopcsa, 1905. 



Mceritliermm trigonodon, Andrews. 



[Plate IX. fig. 5.J 

 1904. Maeritlierium trigodon, 0. W. Andrews, Geol. Mag. [5] vol. i. p. 112. 



Type Specimen. — Posterior portion of right ramus of mandible (PI. IX. fig. 5) ; 

 British Museum. 



This species is distinguished by the form of the posterior lower molar, which narrows 

 posteriorly, the talon consisting almost entirely of one large tubercle ; also by the 

 rapidity with which the teeth decrease in size from behind forwards. 



Form. & Log. — Fluvio-marine beds (Upper Eocene) : north of Birket-el-Qurun. 



