312 TOE WASATCH FAUNA. 



cies of Gahcynns and Temuocyon, aiul has tlie anterior basal tubercle which 

 is wanting' to that genus but present in Aclnrodon. 



Measurements. 



M. 

 Lenj^th of last four molars 040 



Leugth of third premolar Oil 



Width of third premolar ; 006 



Diameters sectorial $ anteroposterior 015 



( transverse 010 



Diameters first molar J '"'*"<'1'°»*«"°'" 008 



( transverse 015 



Diameters second molar J «'^*«^°P°«'*^'"'°'" 0«5 



c transverse COS) 



DiDYMICTIS MASSETERICUS Cope. 



Paleontological Bulletin No. 34, p. 160, 1882, Feb. 20. Proceed. Amer. Philos. Soc, 18.S1, p. 15!), 



Feb. 1832. 



Plate XXIV e; fig. U. 



This species is intermediate in size between the D. hptomylus and the 

 D. dawkinsianus, and is characterized by the peculiar form of its tubercular 

 molar, and the deeply excavated masseteric fossa. It appears to have been 

 a rare species, as only one mandibular ramus was found by Mr. "Wortman. 

 This is broken off in front of the fourth premolar, and supports the last three 

 molar teeth. 



The tubercular molar is subquadrate in form, and consists of three low 

 tubercles in front, and a wide heel behind, which has an elevated posterior 

 border. The tubercular-sectorial has a short and narrow heel. Its anterior 

 cusps are not very acute, and the two internal are equal, and a good deal 

 shorter than the external. The fourth premolar is relatively shorter than 

 in any other sp^ies of the genus, and the posterior marginal lobe is a mere 

 thickening of the edge of the heel. Tliere is a low anterior basal tubercle. 

 The enamel is smooth. 



The ramus is compressed and not deep. The angle is prominent, and 

 is not inflected; it does not extend so far posteriorly as the posterior Ijordcr 

 of the condvle. The inferior border of the masseteric fossa is an antrular 

 line, without abrupt excavation, but the face of the fossa descends rapidly. 

 The anterior border of the fossa is abiiipt and is formed by the usual sub- 

 vertical ridge. 



