310 THE WASATCH FAUNA. 



DlDYMICTIS DAWKINSIANUS CoPE. 



Balletin U. 8. Geol. Surv. Terrs., vi, 1881, Feb. 26, p. 191. 

 Plato XXV a; fig. 11. 



This flesh-eater is represented by more or less imperfect mandibular 

 rami of ten individuals. The most complete of these lacks only the por- 

 tions posterior to the coronoid process, and those anterior to the first pre- 

 molar, and supports all the teeth excepting the first and second premolars. 

 The premolars are all two-rooted excepting the first. The base of the 

 fourth premolar is considerably longer than that of the third. Both of 

 these teeth have a short posterior heel, and above it a cutting lobe. The 

 fourth has a well-marked anterior basal tubercle. The heel of the sec- 

 torial is relatively short, and the anterior portion of the tooth elevated. The 

 anterior and inner cusps are high, and about equal, but the external cusp 

 is much hiffher. The external border of the heel is more elevated than the 

 inner. The tubercular molar is elongate, and has a small triangular ante- 

 rior portion somewhat elevated, in slight resemblance to the sectorial tooth. 

 This portion consists of two opposite cusps and a lower one in front of the 

 anterior inner, which connects with the external by an anterior ledge. The 

 posterior portion has a tubercle on the external side, besides a posterior 

 elevation. The ramus is rather slender, and the masseteric fossa is bounded 

 by a prominent ridge in front, but fades out below. 



The measurements show this to be the smallest species of the genus, 

 being much less than D. leptomylus. 



Measurements. 



Length of dental series, including first premolar OuHi'i 



Length of premolar series 016S 



Length of h.ise of fourth premolar - .0055 



Li'Hjith of base of sectorial 005^ 



Width of base of sectorial at middle -_- 0035 



Elevation of sectorial 0055 



Length of first trno molar 0044 



Width of first true molar in front 0028 



Elevation of first true molar in front 0025 



Depth of ramus at second premolar 00(54 



Depth of ramus at tubercular molar ""■" 



Tliis species is dedicated to my friend Prof. W. Boyd Dawkiiis, the 

 distinguished geologist and paleontologist, of Manchester, England. 



P^ive specimens were obtained from the Wind River basin, and five 

 fiom that of the Big Horn, Wyoming Territory. 



