1884.1 J-^ [Cope. 



identification of mandibles be correct, there is but one inferior premolar, 

 which is not prismatic, but has two divergent roots as in Auchenia. The 

 crown is compressed. In any case this genus is distinct from Palauche- 

 nia Owen, which is said to have the fourth inferior premolar composed of 

 two crescents, somewhat as in the Protauchenia of Branco. There is also 

 a simple conic third inferior premolar according to Owen. The type 

 specimen of the type of Palauchenia, P. magna Owen, consists of isolated 

 teeth put together in a bed of plaster of Paris. While there may be some 

 uncertainty as to the position of the third premolar, I cannot agree with 

 Professor Leidy* in the supposition that these teeth have been inverted by 

 their describer, and really belong to the upper jaw. The specimen is 

 preserved in the museum of the School of Mines, and I did not observe 

 any second one. 



EsCHATIUS CONIDENS, Sp. nOV, 



Primarily established on a superior maxillary bone, which contains all 

 its teeth, which is preserved in the Museum Nacional of Mexico. I cannot 

 distinguish from this individual another one which was found by Mr. C. 

 H. Sternberg in the desert of Oregon, and which is represented by a good 

 many fragments, including parts of both jaws. I describe the ]\[exican 

 specimen first. 



The true molars increase rapidly in size posteriorly. The vertical ribs 

 of the external anterior horns of the external crescents are very strong, 

 and the external wall of the anterior crescent has a low rib on the me- 

 dian line also. The posterior internal crescent of the last superior molar 

 (which is not much worn) sends its anterior horn to the external wall, 

 thus cutting off the posterior horn of the anterior internal crescent. 



31easurements. M. 



Length of the four superior molars 126 



" "M. i 041 



T^. , p-^f .. ( transverse at base 024 



Diameters of M. n. . \ 



^ anteroposterior 044 



Length of M. iii 051 



^\\e foramen infraorhitale aM<e?'ras issues above the anterior rib of the pos- 

 terior crescent of the first true molar. The specimen is from Tequixquiac. 



The Oregon specimen includes a left maxillary and mandibular bones, 

 with the roots or alveoli of the teeth remaining, together with numerous 

 bones of the skeleton. As one or two teeth of the Eolomeniscus hesternus 

 are mingled with the other pieces, it becomes uncertain to which of the 

 species some of the bones should be referred. This is the more difficult, 

 as the superior molar teeth of the two animals are of nearly the same di- 

 mensions. The probabilities are, however, that the greater number accom- 

 pany the species represented by the jaws. I proceed to describe the latter. 



In the maxillary bone the single alveolus of the fourth premolar is close 



Report U. S. Geolog. Survey Terra. I, p. 256. 



