42 MONOGRAPHS OF NORTH AMERICAN KODENTIA. 



example, liul , in every other respect, il is identical with ordinary Carolina 

 hispidus; it will be observed thai it is not in the long-tailed set ; in color il is 

 fully as dark reddish-brown as average Mspidus, while the feet are, after all, 

 only at or barely below ((1.02 or 0.03) the minimum of those of hispidus. 



Thus it is impossible for us to regard "berlandieri" or "toltecus" as spe- 

 cifically differenl from hispidus. There may be those, however, who are ready 

 to admit all we claim, and yet may think these extremes of one species worthy 

 of being distinguished by name as varieties. We have no real objection to this 

 course; and, with a reconstruction of the original diagnosis of " berlandieri", 

 we will present for such naturalists the best diagnosis that can be framed, 

 which may pass for what it may be worth to them: — 



N. hispidus hispidus. — Reddish-brown, lined with black, beneath whitish. 

 Tail rarely equaling body alone. Hind foot not over 1.30 nor under 1.00. 



S. hispidus berlandieri. — Grayish-brown, lined with black, beneath white. 

 Tail sometimes equaling body and bead. Hind foot not over 1.37 nor 

 under 1.10. 



S. hispidus toltecus. — Reddish-brown, lined with black, beneath whitish. 

 Tail rarely equaling head and body alone. Hind foot not over 1.10 nor 

 under 0.95. 



We may observe in passing that the specimens of Sigmodon with the 

 tail as long as the head and body bear a remarkable superficial resemblance 

 to Oryzomys. But Sigmodon may always be known, first, by its hispid pelage; 

 secondly, by its large orbicular ears about equaling in height the distance from 

 nose to eye; thirdly, by the subequality of the 1st and 5th toes — the latter 

 reaching little, if any, beyond the base of the 4th, instead of to its middle joint, 

 as in Oryzomys. These distinctions sometimes come into play, for we have 

 Mexican and Jamaican skins of Oryzomys identical in color with Sigmodon, 

 ami really requiring a second glance to tell them apart. 



Among our United States skins, some, like No. 20, are unusually rusty- 

 colored all over, and represent Arvicola ferrugineus, Harlan. 



As Professor Baird has shown, the Arvicola texiana of Audubon and 

 Bachman is no doubt a Sigmodon. The dimensions assigned render any 

 other interpretation impossible. It is true, we have never seen a Sigmodon, 

 or any other American Murine or Arvicoline, spotted and blotched in the way 

 described; but such coloration is contrary to all analogy in this group, and 

 cannot be considered normal. 



