844 MR. H. MATSUMOTO ON THE GENERA OF 



Genus TiTANOHYRAX, g. n. 



2IegaloJiyrax Sclilosser {iion Andrews, 1903), Zool. Anz., 

 Ba. XXXV. 1910, p. 502; Schlosser, Beitr. z. Pal. n. Geol. 

 Osterreicli-Ungarns u. d. Orients, Bd. xxiv. 1911, pp. 97 & 104. 



This g'enns is diagnosed as follows : — 



Skull very imperfectly known (laying aside the problematical 

 specimen 0. 8801, which may possibly be referred to this genus), 

 but judging from the shape of premaxillae and mandible 

 and from the dental series of both jaws, this genus might be 

 more or less short-skulled and short-snouted. Premaxillse 

 exceedingly elongated supero-posteriorly ; their anterior ends 

 lying a great distance in front of the anterior ends of naso- 

 premaxillary sutures. Judging from the shape of the premaxillae, 

 the external nares may be retired backwards instead of being 

 terminal. Mandibular ramus shallow, without fenestra-like 



opening. Dental formula: ^ ^ " ^ ^ ; I enlarged and tusk-like; 

 none of lower incisors tusk-like. Cheek-teeth selenodont, 



brachyodont, though rather high. All upper P — JW four-cusped. 

 Paraconal and metaconal folds somewhat indistinct except 



in P . Mesostylar fold present in all P — M". Parastylar and 

 mesostylar folds trenchant instead of being rounded. Ridges of 

 lovv'er P,^ — M AV-shaped. Metastylid well differentiated from 



metaconid. Posterior talon of M rather small. 



Genotype: Megalohyrax palceotherioides Schlosser, 1910. 

 This genus includes T. tdiimus, sp. n. ; T. schIosseri,noxQ.ri..; 

 and T. andrewsi, sp. n., besides the genotype. 



Sijnojisis of Species of Titanohj'rax. 



(1) Extremely gigantic species, being the largest oi 



all the hyracoids hitherto known, upper and 

 lower M 2 measuring about 40 mm. in length, 

 whereas those of the next species measure 

 about 30 mm ultimus. 



(2) Gigantic species ; length of upper P and of 



M respectively 7 mm. and 84 ? mm. 

 (Schlosser); that of lower P and of M ,^, 



ca. 70 mm. and 94 mm. respectively (Schlosser). schlosseri. 



(3) Large species ; length of upper P and of M 



respectively ca. 73 mm. and 75 mm. (Schlosser) ; 

 length of lower M 22 mm. (Schlosser), whereas 



the same of the immediately preceding and the 

 next species measures 24*5 mm. and 20 mm. 

 respectively ; lower cheek-teeth of long and 

 narrow type ; snout rather long, the distance 



