SYNOPSIS Ob' THE VERTKBRATE FAUNA OF THE PUKRCO SERIES. 329 



MlOCI,.«NUS KILIIOI.IANLS Sp. nOV. 



Parts of both mandibular rami of two iiulividuals icprcsont this siiecies in 

 my collection. One of these presents the five posterior molars in perfect preservation. 

 The characteis ally the species to some of those of Chriaeus, but the simple first 

 inferior premolar distinguishes it from that genus. After the 3f. minimus and the 

 M acolytus this is the smallest species of Mioclasnus, and its inferior molars have the 

 cusps more acute and elevated than in any other. 



The molars are distinguished from those of several othei" species, including Chri- 

 aeus schlosseriamts, in that they increase in size, regularly posteriorly. The first is 

 thus much smaller than the third, a pi-oportion which is reversed in many other spe- 

 cies. The two anterior cusps are joined much above the level of the heel, which 

 would be thus much below them, but for the fact that its border is much elevated, 

 leaving the median surface a deep basin. The fifth cusp is small and is elevated and 

 close to the foui'th, and is connected with the anterior extei'nal by a cui-ved crest. 

 The edge of the heel is developed into three small cusps, one median and two 

 lateral. The tliiid true molar is quite elongate, and has six well-developed cusps in 

 all. TIk' Hist premolar has a short base, and the principal cusp is truncate behind, 

 and has a shar[) edge in front. The heel is very short and terminates in a small acute 

 cusp, and there is no anterior basal cusp. The second premolar has a small cuspiform 

 heel. There is a weak cingulum on the first premolar and first true molar, but only 

 traces remain on the m. i and ii. Enamel smooth. 



Measiurements. M. 



Length of true molars 017 



„. , ( iinteropostcrior 0045 



Diiimeters of m. i 



^ transverse 00:! 



^. „ ( auteroposlerior 0052 



Diameters of m. ii < 



I transverse 0035 



^. , ... (anteroposterior 006 



Diameter of m. iii < 



( transverse 0035 



Depth of ramus at front of m. i 012 



The two specimens of this species were found in the lowest beds of the Puerco 

 formation by Mr. David Baldwin. It is dedicated to Dr. Henri Filliol, the distin- 

 guished French paUoontologist, whose discoveries in the field of extinct ^lammalia 

 have been so numerous and important. 



MiocL^NUs PROTOoosioiDES Cope ; Amcr. Naturalist, 1882, p. 833; Tertiary Vertebrata, 1885, p. 31(), I'l. XXV f, 

 fig. 17. 



This species has been known hitherto by the last two supeiioi- molars only. 

 At present I have in addition, a fragment of a maxillary bone with the first and sec- 



