MUMD^E—SIGMODONTES— NEOTOMA FLORID AN A. 



17 



the deserts of Arizona and New Mexico. Here the characters tally precisely 

 with those of Hesperomys "sonoriensis" or "gamheli"; indeed, they only fall 

 short of the extreme seen in Hesperomys var. eremicus. The general hue, 

 instead of a rat-brown mixed with blackish, is a dull pinkish fulvous or fawn, 

 especially on the sides, intermixed on the back with a few black hairs. The 

 heels are somewhat less hairy, and the ears a trifle larger, more "foliaceous" 

 and nude. At the same time, curiously enough, the tail, instead of being 

 extremely naked, as was to have been anticipated, is even hairier than in 

 Georgia examples, and approaches the Kansas maximum in this respect. The 

 young animals from the same region are paler gray than usual, corresponding 

 to some samples of Sigmodon "berlandieri "; and some show a slight silvery 

 margin of the ears, as usual in desert Hesperomys "sonoriensis". It is hardly 

 necessary to add that this extreme, witnessed only in animals from the Colorado 

 and Gila deserts, is mixed and obscured in every degree in the animals living 

 in neighboring wooded and watered regions, and is directly connected with the 

 Georgian extreme by Texan, Coloradan, Arkansan, and Kansan examples. 



The supposed Neotoma "mexicana" rests upon these points of coloration; 

 for, as we learn from the table given below, nothing in the way of measure- 

 ments ascribed to it is distinctive. The species was originally based upon 

 a few specimens, all in very poor condition, some of them indicating the 

 extreme stage above described. Had Professor Baird possessed at that time 

 the intermediate scries we now command, it is doubtful whether he would 

 have differed from Geoffroy as to their specific identity with jloridana ; a 

 matter of which, in our mind, there is no question. 



The case of Neotoma "micropus" presents some difficulty, owing to lack 

 of material ; we have nothing additional to Professor Baird's two* types. One 

 of these, No. 561, is so young, that the molars are not cut at all! the skull 

 measuring only 1.08, or about half the normal adult average. We will, there- 

 fore, confine our attention to the other specimen, No. 554. This has the 

 appearance of being mature, or nearly so, except that it is, as stated, in a 

 grayish-slate state of pelage. In the first place, we may dismiss the impres- 

 sion that would be gained from the name " micropus "; the feet being exactly 

 as long as in samples of ordinary Jloridana or "mexicana", and quite as large. 

 Of the many cranial characters adduced, we fail, with the skull in our hands, 



» Nos. 554, 561, published in M. N. A.— Besides these, we find in alcohol, from Santa Rosalia (Couch), 

 two others, Nos. 2699, 2700, labeled "micropus". They are, however, mere sucklings (about three inches 

 Ion-;), and afford no characters at all. 



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