Cope.] S22 [ Dec> 7, 



premolar, and the second and third true molars. The fourth premolar has 

 two external, and one internal cusps, and the true molars have four cusps 

 each. The cusps are of peculiar form. The second true molar resembles 

 a convex body which has been divided by two cuts at right angles to each 

 other, from which the quarters thus produced has spread away from each 

 other subequally. The external faces of the cusps are convex. The 

 apices are acute. The last superior molar is larger anteroposteriorly than 

 transversely. The fourth premolar (supposed) is two-rooted. 



These molar teeth remind one of the inferior molars of Ptilodus, through 

 they differ much from them. The genus is probably nearer to Gatopsalis, 

 and belongs to the Marsupial order. The presence of only two series of 

 cusps in the superior molars, distinguishes it from these genera, which 

 have presumably three series of such cusps. Lemoine has shown this to 

 be the case in Neoplagiaulax. 



Char, specif. The external cusps of the fourth premolar are flattened 

 on the external side, and lean a little inwards. The internal cusp (proba- 

 bly homologically the anterior) is opposite the anterior external, and 

 has a convex internal face. Its apex is acute and compressed ; the apices 

 of the external cusps are trihedral and acute. 



The cusps of the second true molars are more widely separated trans- 

 versely than anteroposteriorly ; that is, the longitudinal fissure is wider 

 than the transverse. The apices are all acute, the internal trihedral, the 

 external more compressed. 



The transverse diameter of the last true molar is smaller than that of 

 the second true molar, while the longitudinal is nearly the same. The 

 crown projects convexly posterior to the posterior pair, and there is a small 

 tubercle at the anterior base of the external anterior cusp. 



None of the teeth preserved display cingula. The bases of the crown 

 are smooth, but the cusps are sharply and finely parallel-grooved on their 

 external faces. 



Measurements. M. 



-.. . ._ r anteroposterior. ... , 0030 



Diameters of P-m. iv< , nnna 



I transverse 0038 



_.. „ .. c anteroposterior 0033 



Diameters of m. u r „„„_ 



t transverse .., 0035 



_,. , ... r anteroposterior 0035 



Diameters of m. iih x _- oa 



{. transverse 0030 



D. Baldwin, discoverer. 



Catopsalis fissidens, sp. nov. 



This Marsupial is represented by a portion of the lower jaw which sup- 

 ports the molar teeth. The first, which is probably the fourth premolar, is 

 represented only by its single root, which fills a round alveolus near the 

 anterior base of the first true molar. 



In size this species is intermediate between the small C. foliatus and the 

 large G. pollux. The first molar is the longer and narrower, and the 



