CIRCUS SWAINSONII. 
which has not been very limited, 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 auricapil/us, Sw. ; and among the indivi- 
duals of this flock, a distinct discrepancy, 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 together. 
