Allen.] 286 [February 4, 



of the Isthmus of Panama. 1 The synonyms cited will doubtless be 

 sufficient to render clear the changes of nomenclature here intro- 

 duced (the names of the United States species used in Baird's Mam- 

 mals of North America being always given), the detailed descriptions 

 of the forms recognized, and the discussion of their character and 

 relations being reserved as the subject matter of the more extended 

 memoir referred to above. 



Genus Sciurus. 



1. Sciurus cinereus. 



a. var. cinereus. 



Sciurus cinereus Linn., Syst. Nat., I, 64, 1758. — Baird, Mam. N. Am., 

 248, 1857. 

 Hab. Atlantic States north of Virginia. 



6. var. niger. 



Sciurus niger Linn., Syst. Nat , i, 64, 1 758. — Allen, Bull. Mus. Comp. 



Zool., ii, 176, 1871. 

 Sciurus vulpinus Gmelin, Syst. Nat., I, 147, 1788. — Baird, Mam. 



N. Am., 246, 1857. 

 Sciurus capistratus Bosc, Ann. du Museum, I, 181, 1802. — Bachman, 



Proc. Zool. Soc. Lond., vi, 85, 1835. 

 Hab. Atlantic States south of Virginia; Gulf States west to 

 Texas? 



1 I should here state that the following resume, as well as the proposed mono- 

 graph, is based mainly on the immense stores of material that for many years have 

 been accumulating at the Museum of the Smithsonian Institution, and which have 

 been kindly placed in my hands by Prof. Baird for elaboration. In addition to this 

 rich material, I am also permitted the use of that contained in the Museum of 

 Comparative Zoology, which, so far as the forms of Eastern North America are 

 concerned, far exceeds that of any other collection. The material at my command 

 hence ranges from thirty to several hundred specimens of each of the greater part 

 of the species of North American Sciurldce. As indicative of the recent increase 

 in the material at the Museum of the Smithsonian Institution, I may add that while 

 in 1837 there were but two specimens of Sc iur us " Fremonti "• extant, I have had 

 access to more than fifty skins, many skulls and to specimens in alcohol ; the five 

 specimens of Sciurus "Richardsoni" have been increased to forty; of Spermophi- 

 lus Harrisi, from three to thirty-five; of Spermophilus Mchardsoni, from none to 

 above seventy, etc. Of Spermophilus tridecem-lineatus I have had before me about 

 one hundred and sixty; of the Sciurus hudsonius group, upwards of two hundred 

 and fifty; and of the Tamias quadrivittatus group, nearly one hundred and 

 seventy-five, and very large and satisfactory series of nearly all the other species 

 mentioned in the following synopsis. 



