Cope.] 55b [ Jan . , 5j 



longer than the first as in M. bucctclentns, although the difference in size is 

 very evident. The third is smaller than the first, and ovoid in outline, while 

 the first and second are subquadrate. The external cusps are conic and 

 widely separated and the intermediate areas are distinct. There is a cingu- 

 lum all round the crown of the last two, and round that of the first except 

 at the inner side, and at the anteroexternal angle. 



The last three inferior premolars are higher than long at the base, and 

 are compressed and the apex acute. The posterior edge of the third and 

 fourth is truncate, and simple. Each has a posterior cingulum which forms 

 a narrow heel on the fourth. No other cingula. Of the true molars 

 only the second is wanting. The form of these is like those of the M. ferox, 

 with the cusps more prominent. The first only has trace of the anterior 

 V ; in the others, the two anterior tubercles are opposite and connected by 

 a short anterior ledge. The heel of the first consists of a basin bounded by 

 these tubercles, of which the external is pyramidal and largest. The 

 median posterior is small. The heel of the third is narrow and prominent, 

 and the internal lateral tubercle is represented by a short raised edge. The 

 enamel of all the molars is wrinkled, and the inner side of the premolars 

 is grooved with the height of the crown. A weak external cingulum on 

 M. iii. 



Measurements. M. 



Length of last three superior molars 0265 



Diameters of M. i \ anteroposterior 0060 



C transverse 0060 



Diameters of M. ii $ anteroposterior .0062 



c transverse 0072 



Diameters of M. iii { anteroposterior. 0047 



I transverse 0060 



Length of last inferior molars. 0340 



Length of last three premolars 0140 



Length of P-m. iv 0050 



Elevation of P-m. iv 0050 



Diameters of M. i { anteroposterior .0057 



( transverse 0042 



Diameters of M. iii { anteroposterior 0070 



<- transverse 0035 



Rather larger than the pine weasel, Mastela americana. 



MlOCL^NTJS COKRUGATUS, Sp. nOV. 



This species is known from a right maxillary bone which contains the last 

 four molar teeth, with parts of pelvis and other bones of one individual. 



This species is intermediate in size between the M. protogonioides and 



M. ferox, as the following measurements of the second superior true molar 



show : 



M. protogonioides. M. corrugatus. M. ferox. 



Diameter, transverse Oil .0118 .015 



anteroposterior 008 .010 .013 



— 



