SCIURIDiE-SCIURUS NIGER AND VARIETIES. 723 



northern. Judged by this standard, the specimens from Saint Louis, Mo., 

 must be regarded as fully as large as those from farther north, if not, indeed, 

 a little larger. 



The geographical variation in color in var. ludovicianus consists, as 

 already noticed, in an increasing pallor northward and toward the dryer por- 

 tions of the plains, and, in the country immediately bordering the Missis- 

 sippi, in a strongly marked increase in color southward. 



Geographical distribution. — Vars. cinereus and niger occupy the Atlan- 

 tic slope from New York southward, var. niger being found westward in the 

 Gulf States as far as Eastern Louisiana. Var. cinereus has been reported as 

 common on Long Island, and as occurring as far eastward as Massachusetts, 

 but, if ever found in the last-named locality, can occur there only very rarely. 

 Both var. cinereus and var. niger occur in Maryland and Virginia, where their 

 habitats overlap, and the two forms interblend. Probably var. cinereus ranges 

 farther southward along the mountains of the interior than along the coast. 

 Var. ludovicianus appears to occupy nearly the whole region drained by the 

 Mississippi and its eastern tributaries, and extends up the Missouri to above 

 Fort Randall, and occurs along the Arkansas, the Red, and the other princi- 

 pal rivers that come down from the Plains as far as they are regularly bor- 

 dered with timber. The westernmost localities represented by the specimens 

 before me are the Republican Fork and the vicinity of Fort Cobb, Indian 

 Territory. It is found throughout a large part of Texas, and doubtless 

 ranges far into Mexico. It has even been reported as occurring as far south 

 as Guatemala,* but I think the identification in all probability erroneous. 



Synonymy and nomenclature. — The earliest available name for the 

 specific designation of the Fox Squirrels is doubtless niger, used by Catesby 

 in 1743, and adopted by Linnseus in the tenth edition of the Systema Naturae 

 (1758), based on the Large Black Squirrel of Catesby, which unquestionably 

 refers to the dark phase of the Southern Fox Squirrel. Immediately follow- 

 ing it, on the same page of this edition, is the name cinereus, generally con- 

 sidered as referring to the Northern Fox Squirrel, the Cat Squirrel of Bachman. 

 The only objection to niger as applicable to the whole group is that it refers to 

 only a single phase of coloration, and not to the most prevalent one, though 

 a very common one. In view of the great frequency of the black and dusky 

 phases of coloration, the objection is one of no great importance, and I hence 



• Tonics, Proc. Zool. Soc. Lond. 1861, p. 281. 



