340 THE rUERCO FACNA. 



is probable but not certain. I liave therefore not referred it to its position 

 in the genus as determined by the second inferior molar tooth, although 

 that tooth is preserved 



The second or third inferior premolar is a rather large tooth formed 

 somewhat after the pattern of the corresponding one of the species of Hap- 

 locotius. It is compressed, has an elevated confluent anterior lobe, a large 

 median lobe, and a low, short heel. The posterior face of the median lobe 

 is truncate, and is bounded by two edges, of which the internal is continuous 

 with the inner edge of the heel. The latter has a weak median keel wiiich 

 rises to a jjoint of the posterior margin. Surface smooth, no cingula. The 

 second inferior true molar has a large, wide heel, whose external side sup- 

 ports a large tubercle. The posterior border is raised, and the size continues 

 round the inner side, supporting two small lobes, one posterior, the other 

 internal. The anterior cusps are large and closely approximated, and there 

 is a small anterior inner cusp. This is a little inside of the middle line and 

 is connected with the external anterior cusp by a ledge. No cingula. 



Mcasurcmentn. 



M. 



Ltngtli of Pm. iii 0080 



Width Pm. iii .at middle of base 0038 



5 anteroposterior OOliO 



Diameter M. >>• hransver^e OOGO 



The structure of the second inferior molar places this species between 

 the M. turffidus and the M. hrachysiomus. It is as large as the former, but 

 had larger jaws and muzzle, judging by the size of the premolar tooth. 



From the Puerco Beds of New Mexico, D. Baldwin. 



MiOCLyENUS PROTOGONIOIDES Cope. 



American Naturalist, 18*2, p. 833, (October, published Sept. 28). 

 Plate XXV f, fig. 17. 



The third in size of the genus, represented by the superior true 

 molars. It is an exaggerated form of the M. suhtrlgonus. The internal 

 angle of the V, as well as the intermediate tubercles at the ends of its limbs, 

 are distinct. Cingula extending entirely arountl the crown, the posterior 

 with a small tubercle on the M. ii as in A. subtrigoitits ; none on M. iii, which 

 i.s .7.") the area of the M. ii. Diameters M. ii, anteroposterior, .008; trans- 

 verse, .010. Diameters M. iii, anteroposterior, .007; transverse, .009. 



From the Lowest Puerco of New Mexico, D. Baldwin. 



