42 



MONOUltAl'IiS (3F NOUiri AMERICAN ItODENTIA. 



u irDi 



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o.X!im|tlc. Hut. ill every oilier respect, it is identical with onlinnry Carolina 

 Uhpidus; it will i)(^ observed tluit it is not in the long-tailed set; in color it is 

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

 only at or banily below (0.02 or 0.03) the niiiiiiinnn of those of liixpidus. 



Tims it is impossible for us to regard "lierlaiidieri" or "toltecus" as spe- 

 cirically diilereiit from Mspidus. There may be tiiose, however, who are ready 

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

 of iieiiig dislingiiished by name as varieties. We have no real objection lo this 

 cour,'<e; and, with a reconstruction of the original diagnosis of "berlandii^ri", 

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

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



S. hkpidus hiapidus. — Reddi.sh-brown, lined with black, beneath whitish. 

 Tail rarely eciualiiig i)ody alone. Ilind foot not over l.aO nor under 1.00. 



6'. /linjiidus beilaudieii. — Grnyish-brown, lined with black, beneath white. 

 Tail sometimes eipuding body and head. Ilind foot not over 1.37 uor 

 under 1.10. 



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

 Tail rarely ecpialing head and body alone. Ilind foot not over 1.10 nor 

 under 0.95. 



We may obseive in jiassing that the specimens of SIgmodon with tho 

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

 to Oyijzomys. But Sigmodon may always be known, first, Ity 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 Onjzomys. These distinctions sometimes come into play, for we have 

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

 and 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 ferruginem, 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. 



