468 GEOLOGICAL SUEVEY OF THE TEEKITOEIES. 



tion, which is separated from the median external by a deep notch. It 

 is entirely on the inner side, and sends a cingulum to the external base 

 of the outer median. Fourth molar largest, heel narrowed, with three 

 tubercles. 



Measurements. 



M. 



Length of last three molars - 0060 



Length of second true molar 0020 



Elevation of second true molar 0022 



EMBASSIS, Cope. 



Synopsis New Vertebrata Colorado, 1873, p. 4. 



This genus was instituted to receive a single species supposed to be 

 allied to those of the preceding genus. Its prominent character con- 

 sists in the development of the anterior three cusps at the expense of 

 the posterior two ; the former forming a trihedral mass, to which the 

 latter form but a basal appendage. In the typical species, the last in- 

 ferior molar exhibits the same reduction in size seen in Domnina, and, 

 as I find that a second species agrees with it in all important respects, 

 characters derived from it induce me to refer Umhassis to a nearer rela- 

 tion with that genus than I have heretofore indicated. This I formerly 

 described as Herpetotheriwn marginale, but it evidently pertains to a 

 distinct genus, characterized by the presence of only three true molars 

 of the inferior series. These present the general characters of those of 

 Umbassis alternans, and, like it, differ from those of Domnina gradata in 

 having the outer posterior cusp a cone instead of a crescent. The last 

 premolar is composed of two conic cusps, the inner the smaller, and sep- 

 arated from the outer by a deep notch. The other premolars are wanting 

 in the specimen ; but the characters observed indicate affinity with the 

 Soricidw rather than the Talpidce, and probably a smaller number of 

 teeth than in Jlerpetotherkmi. 



Embassis alteenans, Cope, Synopsis, Yert. Colorado, 1873, p. 7. 



Heel of molars with two low tubercles ; the last tooth smaller than the 

 penultimate. An antero-external cingulum. 



Measurements. , 



M. 



Length of two last molars 0.0038 



Length of third molar .0020 



Elevation of third molar 0018 



Embassis MAEGiNAiiis, Cope. Kerpetotherium, marginale, Cope, loo. cit, 

 1873, p. 6. 



Anterior cusp close-pressed to the median pair, and united with 

 them above the base, forming a triquetrous mass elevated above the 

 heel. The cusps of the heel two, more than usually elevated, and acute. 

 A cingulum descending from the anterior and posterior cusps to the base 

 of the median on the outer side. Only two cusj)S on the heel of the last 

 molar. Cusps of the last premolar acute, smooth, and recurved. 



This species is about as large as the Domnina gradata, but differs from 

 it in many respects besides those already noted. The first true molar, 

 though larger than the third, is not so much so as in the D. gradata; the 

 anterior crescents are less open, the heel more contracted, &c. 



