78 FIELD AND FOREST. 



the toes, while the other limbs were black ; other specimens had small 

 white patches quite unsymmetrically disposed over the dorsal surface 

 and on the limbs, presenting an irregularly pied appearance. In one, 

 small white patches also appeared irregularly on the throat and breast. 

 In S. Boothice the white spots were confined to the ventral surface of the 

 body, which normally is rufous, but sometimes wholly white. In 

 intermediate examples the white was sometimes an irregular band 

 along the median line, but not generally symmetrically developed on 

 the two sides of the median line ; in other cases the white was broken 

 tup into patches, in some symmetrically disposed, in others very un- 

 :symmetrical in developement. Several specimens were symmetrically 

 marked with white arm-pits, and irregular spots of white on the throat 

 and breast. 



It hence follows that Mr. Ryder's second suggestion is open to 

 modification, — that is, that while in perhaps most cases where varia- 

 tion from the normal color takes place, through albinism, in feral 

 animals, the white areas are not invariably symmetrically disposed. 

 Among birds tending to albinism, I think it may be safely stated, as 

 a rule, that where white patches appear they are not symmetrically 

 developed on opposite sides of the body. 



J. A. Allen. 



"Wallace's Geographical Distribution of Animals.* 



The indications as to the relations of the realms or regions furnished 

 by the different classes of animals are very conflicting, and depend in 

 a great measure, as might naturally be- expected, on the ability of in- 

 dividuals to extend their limits, or the reverse. The two classes that 

 perhaps are most antithetical in this respect are birds and inland fishes. 

 The former are in an eminent degree fitted for the extension of their 

 range, and consequently for accommodation to the "lay of the land;" 

 while the latter are restricted by sharply-defined boundaries within 

 very definite areas, and physiologically prevented from extending their 

 range either over the land or across the expanse of ocean to any great 

 extent. The two classes are also antithetical in another respect, inasmuch 

 as the birds are a highly specialized group, very liable to modifications 



- Continued from page 74, October number. 



