Bulletin American Museum of Natural History. [Vol. Ill, 



half both the upper and lower borders are greatly produced, 

 especially the lower, which is somewhat everted or deflected 

 upward and incurved, the two produced borders thus forming 

 between them a deep groove on the external surface of the 

 anterior half of the malar bone, the groove being deepest anteri- 

 orly and there partly covered by the incurved lower edge of the 

 malar. The square process occupying the anterior fourth of the 

 malar in the L. sylvaticus group is in effect extended backward, 

 gradually narrowing till it becomes obsolete posterior to the 

 middle of the malar bone. The form of this bone is thus very 

 different in the two species when viewed either from below or 

 from the side. The postorbital processes touch the brain-case at 

 tip but are not fused with it, as in the L. aquaticus group. 



In accordance with the great development of the external ear, 

 the auditory bullae are correspondingly enlarged. 



The only species with which this needs comparison is apparently 

 the Lepus verce-crucis, from the opposite coast of Mexico. 



45. Tatusia novemcincta (Linn.). Male, Volcan de Fuego, 

 Tonila, Jalisco, Dec. 27, 1889. 



46. Didelphys (Micoureus) murina Linn. Six specimens, 

 four males and two females, Santo Domingo de Guzman, Tehu- 

 antepec, April 25 to May 2, 1890. 



, These specimens are doubtfully referred to this species, which 

 they resemble in size. None of them, however, have the general 

 color above " bright rufous," or "deep dull rufous," as described 

 respectively by Alston and Thomas. Some are clear ashy, others 

 ashy brown, with a very faint fulvous or exceedingly slight 

 rufescent tinge. 



Additional Notes on Mexican Leporidae. Since the above 

 was put in type I have had opportunity, through the kindness of 

 Mr. F. W. True, Curator of the Department of Mammals in the 

 United States National Museum, of reexamining specimens of 

 Lepus from Merida, Yucatan, and Mirador, Mexico, referred by 

 me in 1877 (N. Am. Roden., pp. 365 and 361) respectively to 

 Lepus aquaticus and L. palustris. 



