1883.] ^^^ [Cope. 



rudimental. The feet were plantigrade and the claws prehensile. The 

 fore feet were well turned outwards. There were in all probahility mar- 

 supial bones, but whether there was a pouch or not cannot be deter- 

 mined. These points, in connection with the absence of inflection of the 

 angle of the lower jaw, render it probable that the nearest living ally of 

 the MioclcBnus ferox. is the Thylacynus cynocejjhalus o( Tasmania. The pres- 

 ence of a patella distinguishes it from Marsupials in general. Its den- 

 tition, glenoid cavity of the skull and other characters, place it near the 

 Arctoeyonidce. Should the forms included in that family be found to pos- 

 sess marsupial bones, they must probably be removed from the Creodonta 

 and placed in the Marsupialia. 



This species is about the size of a sheep. The bones are stated by Mr. 

 Baldwin, who discovered it, to be derived from the red beds in the upper 

 part of the Puerco series. 



MlOCL^NUS BUCCULENTUS, sp. nOV. 



A part ot the right maxillary bone which supports three molars indi- 

 cates this species. The molars are P-m iv, M. i and M. ii, This series is 

 characterized by the remarkably small size of the fourth premolar, and 

 large size of the second true molar. The first true molar is intermediate. 

 The fourth premolar consists of an external cone and a much smaller in- 

 ternal one. There is a weak posterior basal cingulum. The reduced size 

 of the internal cone suggests the probability that the third premolar has 

 no internal cusp, and that there may be but three premolars. In either 

 case the species must be distinguished from Miodcenus. 



The first and second true molais have conic well separated external 

 cusps, antl a single pyramidal internal cusp. The intermediate tubercles 

 are distinct. There is a posterior cingulum which terminates interiorly in 

 a flat prominence. There is an anterior cingulum aud a strong external 

 one, which form a prominence at the anterior external angle of the crown. 

 Enamel wrinkled. 



Measurements of Superior Molars. M. 



Length ot bases of P-m. iv M. i and ii 0180 



Diameters P-m. iv | anteroposterior 0040 



t transverse 0046 



Diameters of M. i | anteroposterior 0060 



l transverse 0065 



Diameter of M. ii | anteroposterior 0070 



<- transverse 0085 



MlOCL^NUS SUBTRIGONUS Cope. 



This species has been known hitherto* from a palate with three molars. 

 I am now able to give the characters of the inferior molar series, which 

 have been found, by Mr. Baldwin, associated with the true superior molars. 

 Of the latter it may be remarked that the second true molar is not so much 

 *Amerlcan Naturalist, 1881, 490-1. 



PROC. AMER. PHILOS. SOC. XX. 113. 3r. PRINTED MARCH 16, 1883. 



