SOIDRlD^-GROOUAPniGAL DISTRIBUTION AND VARIATION. G43 



Owing to the great tondcncy to variation exhibited l)y tlie Rquirrelii 

 everywhere, both indiviilually and geographically, especially among Uie Sciuri, 

 it i» difficult, with our present inexact knowledge of the sulijcct, to compare 

 Rutigfactoriiy one geographical region with another in respect to the number 

 of species actually existing in difi lent parts of the world. The species 

 occurring in North America north of Mexico have been studied more care- 

 fully, and with far better facilities in the way of material, than those of any 

 other equal area, with the result of greatly reducing the number of species 

 formerly recognized. During the last twenty-five years, the number of sup- 

 posed North American Sciuri has been reduced from twenty-seven species to 

 six, with six or seven additional geographical races, or subspecies. It is but 

 fair to suppose that those of Mexico, of Asia, and of Africa, when equally 

 well known, will be similarly reduced, especially those of Asia, where authors 

 have evidently excessively multiplied synonyms.* Professor Baird, in 1857, in 

 elaborating the large amount of material then at his disp ^^al, found it neces- 

 sary to reducu the number of North American Sciuri (exclusive of those of 

 Mexico), from the twenty-seven previously supposed to exist to twelve,t 

 while the subsequent great increase of available material now renders it appa- 

 rent that the number of non-intergrading forms is one-half less than he felt 

 authorized in retaining. 



In respect to the subject of individual and geographical variation among 

 our Squirrels,! cannot refrain from quoting Professor Baird's judicious observa- 

 tions, especially since be was the first to call attention to the great variability 

 of the North American Sciuri. In his great work on the Mammals of North 

 America, published in 1857, ho says: — 



"The determination of the species of Squirrels of North America has 

 always been a matter of great difficulty, owing to many different reasoDi. 

 The species themselves exhibit an unusual tendency to run into varieties of 

 color, among which red, gray, and black t ~ ^,he predominating ones, with oil 



* Dr. Oisy, in 1867 (aee Add. aad Ha^;. Nftt Hist. 0.1 ler. vol. zx), recognixed /ortji-thn» ■peciee 

 of JWari (= IfaemI >ud Miiri Gray) from Aiin, tea tra.n Africa, BDd /or(^ from Amerioa, nearly half of 

 Um Uttar beiiiK daaeribed by him (to a aingle p>p«r) M nr" (be«idM many " yarietiea"), all ftom ths 

 WMBMr parU of the two America*, while a large proportion of the name* previoosly given by other 

 antbori to tba Mart of Ueiico and Central and Bonth America were left anidentifled. A single species 

 {SoUmu rul§ari$), qnito variable in color, he properly allowed to represent tbegennsin Enropv; while, in 

 raa|.«e( to tlM> rpeeies of North America, he wisely accepted the reduetions made by Professor Baird. 

 Wit J • lai§a aOicant of material before me, I am nnabie to recognize more than foorteen species, with a few 

 additional varieties, and believe that this nnmber will have to be >tUl farther rednced as additional 

 maUtitl bae— «a aroiaslble. 



t Two of ihcae were doobtfolly admitted. 



