(JH 



MON()(H{AI'JI8 OF NOHTII AMKKICAN KODENTIA. 



M. Dc Siiussurc! Im« been iiHin! tbitunnto in handling Mexican Ilesperomys 

 tliiin lir wiis ill (hi8 case, for one of these specimens is an adult and the other 

 a yoimj,' cxiimplc of /ruco/ius; neither of them shows the sliKlitest departure 

 Ironi the ordinary ty|)e. We Imve not mot with either of these names in 

 print, and il', indfcd, they were never published, we shall regret their appear- 

 ance on our i)age ; for a synonym once rooted is havd to eradicate. 



Now, passing over for a moment a certain Eastern Unitc<l Slates variety 

 of liuaipux tliiit w<; shall Ix; |)r<'pared to establish lliither on, and likewise post- 

 poning consideration of the names "cognatus" and "maniculatus", as these 

 are best treated in connection with var. gosni/pinus, we will examine several 

 western names that we claim iiave no ioundation. 



Th(! iirst western "s])ecies" (so-called) that we shall notice, is Hesperomys 

 "texaiius" of Woodhouse (type. No. 2551), Mus. Smiths., in alcohol, from 

 Western Texas). The author's description shows nothing whatever different 

 from ordinary kitcopiis, except small size (length, 2.10; tail the same) ; but 

 this, of course, is matched by any other nngrown kucopus. The character, 

 "legs white on their inner surfat.-e only" («'. e., color of back extending over 

 outsidt! of legs), is not of the slightest consecpieiici!, since plenty of typical 

 leacopus show it, especially immature ones. In admitting the species, wliicli 

 he places next to le.ucopus, Professor Baird found it "very difficult to eharac- 

 terize it as distitict from kucopus, although it is very probable that the two are 

 distinct." He assigns "size and proportions about as in kucopus;" and his 

 table of measurements docs not show any discrepancy. The ears are not 

 smaller, as given by both these authors. We fail to appreciate any distinction 

 in color, except a slight average paleness ; and for this we shall be abundantly 

 prepared after we have looked up var. sonorknsis. Finally, we tabulate the 

 several specimens that have been referred to kxanus ; it is the more surpris- 

 ing that Dr. Woodhouse should have described his specimen as distinct, since 

 he was well acipuiinted with kucopus, which, as he says, is "common in the 

 Indian Territory and Texas." 



