ON FOSSIL HYRACOIDS FROM THE FAYfi-JM. 839 



42. Meguloliyrax Andrews and Titanohyrax^ g. n. — A Revision 

 o£ the Genera of Hyracoids from the Fayum, Egypt. 

 By H. Matsumoto *. 



[Received October 18, 1921 : Read November 22, 1921.] 

 (Text-figures 1-6.) 



In the course of my re-study of the fossil Hyracoidea of the 

 Fayum, Egypt, based upon the material belonging to the American 

 Museum and the British Museum, I found that Schlosser's 

 identification of Andrews's genus Megalohyrax is incorrect, 'the 

 type-specimen of the genotype Meg. eoccemis Andrews belonging 

 not to Schlosser's ^'^ Megalohyrax" but to his '■'■ Mixohyrax." 

 Consequently, his '■'• Mixohyrax"' should be called Megalohyrax, 

 while his "' Megalohyrax^' wants a new generic name. I propose 

 to call it Titanohyrax, g. n. 



I have the pleasure to express here my hearty thanks to 

 Dr. Arthur Smith Woodward and Dr. Charles W. Andrews, 

 by whom I was permitted to examine the material belonging to 

 the British Museum. 



Genus Megalohyrax Andrews. 



Megalohyrax Andrews, Geol. Mag., Decade iv. vol. x. 1903, 

 p. 341 ; Andi-ews, Brit. Mus. Cat. Tert. Vert. Fayum, Egypt. 

 1906, p. 92. 



Mixohyrax Schlosser, Zool. Anz., Bd. xxsv. 1910, p. 502 ; 

 Schlosser, Beitr. z. Pal. u. Geol. Osterreich-Ungarns u. d. Orients, 

 Bd. xxiv. 1911, pp. 98 & 115. 



This genus is to be re-diagnosed as follows : — 



Long-skulled and long-snouted. Premaxillae long, but not 

 especially elongated supero - posteriorly. Nasals long, with 

 acutely-pointed anterior ends, , which lie nearly as anteriorly as 

 the anterior ends of premaxiilpe and a certain, but not very great, 

 distance in front of the anterior ends of naso-premaxillary sutures. 

 External nares not retired at all. Upper surface of skull very 

 rough, with irregular pits and grooves with intervening ridges. 

 Mandibular ramus shallow, with a large fenestra-like opening on 

 the iinrer surface. Dental formula : 'l--^\'-\; I^ ^^d Ig enlarged 

 and tusk-like. Cheek - teeth bunoselenodont, brachyodont. 

 Upper P ", and usually also P'\ three-cusped ; P — M , and 

 sometimes also P\ four-cusped. Paraconal and metaconal folds 



* Communicated bj' Dr. C. W. Andeews, F.R.S., F.Z.S. 

 Pkoc. Zool. See— 1921, No. LVl. 56 



