22 



Pkocamelus occidentalis Leidy, Anc. Fauna Dakota and Nebraska, 

 p. 151. 



Specimens in fine preservation, but referred with some doubt as above- 

 The dimensions of the teeth are intermediate between those of the 

 species above named, and the P. gracilis, Leidy. 



Merycodus gemmifer, sp. nov. 



A small ruminant represented by jaws and teeth of three iudividnals 

 found in association with the species above described by the writer. 

 These embrace only the true molar teeth in good preservation, They 

 resemble those of M. necatus, Leidy, in form and size, but differ in having 

 a rudimental column between the principal columns at their bases, a 

 character which I have satisfied myself does not exist in the Niobrara 

 specimens described by Dr. Leidy, by autopsy. These only appear on 

 the grinding faces after prolonged attrition. First molar equal to the 

 last premolar in anteroposterior diameter. 



Measurements. 



M. 



Length of four posterior molars 0.037 



Length of true molars 030 



Length of second molar 090 



Width of second molar 010 



Length of third molar 013 



Width , 006 



Depth of jaw at second molar 015 



PROBOSOIDIA. 



Mastodon proavus, Cope. Synopsis Vertebrata, Colorado, 1S73, 

 p. 10. 



TESTUDINATA. 



Style:\[ys ?niobrarbnsis, Leidy. Abundant. 



SUPPLEMENTAEY ADDITIONS 



TO THE '• Synopsis of new vertebrata, from the territory of 



COLORADO, 3 873." 

 MENOTHERIUM LEMURINUM, gCU. Ct Sp. nOV. 



This new genus is probably quadrumanous, and allied to the lemurs, 

 but as I only possess portions of two mandibular rami with dentition, a 

 more exact determination will be looked for with interest. It is the 

 first indication of the existence of monkeys in the Miocene formation of 

 the United States. 



There are at least two premolars and three molars in the inferior series, 

 those anterior being last in the specimens. The last premolar is some- 

 Avhat sectorial in form, having a compressed but stout median cusp, a 

 broad heel behind, and a small tubercle in front. The last molar is 

 rather smaller than the others, and with a slight posterior or fifth 

 tubercle. The molars support four tubercles nearly opposite in pairs, 

 and connected by a diagonal crest, so that when the crown is worn an 

 S-shaped figure results. The two alveoli in front of the last premolar 

 may have contained each a separate tooth, or a single tooth, longer than 

 any of the others. 



