CIRCUS SWAINSONII. 



which has not been very hmited, would incline me to regard the size of external parts, parti- 

 cularly in certain classes of animated beings, not entitled to consideration, as a specific 

 character; nor would I even be disposed to admit a greater size of all the parts of the body, as 

 a proof that an individual in which such a condition was manifested, was of a different species 

 from another, from which it only differed in being a trifle larger. To this conclusion I should be 

 led, from having observed among some species, — of Ploceus in particular, that some individuals 

 were often to be seen considerably larger than others, where no doubt could exist as to their 

 all being of the same species. During the late expedition into the interior, a well-marked case 

 in point occurred. In a cluster of reeds, skirting a pool of water, some way to the northward 

 of Latakoo, we found an enormous flock of Ploceus auricapillus, Sw. ; and among the indivi- 

 duals of this flock, a distinct disci epancy, in point of size, was evident ; though not the slightest 

 difference could be detected, either in the form or structure of their nests, nor in the shape nor 

 markings of their eggs. Many of the smallest, as well as of the largest individuals, were killed ; 

 and no differences could be discovered, on the most minute examination, save that the latter 

 were about a third larger than the former. As I have appeared to lay some weight upon the 

 character of the nests, in proof of these birds being of the same species, I may merely observe 

 that each species of Ploceus which inhabits South Africa, forms its nest differently ; and the 

 differences are very palpable, when those of each sort are compared toaetlier. 



