HISTORY OP THE ROTIFERA, OR WHEEL ANIMALCULES. 485 
then, drawing off through the great sinus a portion of the 
circling cloud of pigment, deposits it atom after atom in the little 
cup-shaped receptacle until it is full. Meanwhile the accumu- 
lating contents have been, and are still, whirled round and round 
within the cup by the action of the interior cilia, which process, 
probably aided by the secretion and admixture of some animal 
glue, gradually consolidates them into a tiny globular pellet, whose 
shape is moulded by that of the cup. Suddenly now we see the 
animal bend itself forward till the cup is brought into contact 
with the upper edge of the case ; it remains so bent for an 
instant, and then as quickly resumes its upright posture. The 
cup, however, is now empty ; for the consolidated pellet, a little 
globule exactly agreeing in shape and size with those of which 
the case is made up, but differing from them in being of a deep- 
red hue, has been left on the edge of the case, where it firmly 
adheres. The process under these circumstances occupies from 
two and a half to three and a half minutes ; at the end of which 
interval another pellet is completed and instantly deposited. So 
the work goes on ; the animal occasionally shifting partly round, 
depositing two or three at one spot, then a few at another part 
of the edge, not proceeding regularly along the horizontal 
course, so that the unfinished ed 6 of a case is always uneven ; 
while yet, on the whole, the edifice heightens with pretty fair 
equality. The profusion of solid matter in suspension, available 
for the animal's purpose, causes the process of manufacturing 
these bricks to be much more rapid than it would be under 
ordinary circumstances. The material commonly collected ap- 
pears to be the organic matters which form the residua of 
digestion, with which their colour well agrees ; and these are 
doubtless obtainable only at intervals and in small quantities. 
Thus we have here an animal of invisible minuteness which 
displays more than merely constructive powers. It had been 
surely a most interesting phenomenon if the tiny creature had 
formed its case, like the caddis-worm of our brooks, out of 
ready-made materials which it picked up and appropriated, 
and no more. But, in addition to this, there is the instinct of 
fashioning the crude materials into solidity and shape, — a 
true manufacturing- process. Here is not only a clever archi- 
tect and bricklayer who builds his symmetrical house, brick 
by brick in regular courses, cementing each with a mortar 
which, like the Aberthaw lime, sets and hardens under water ; 
but an artisan who collects various sorts of crude substances, 
and, with the aid of certain machinery peculiar to himself, 
consolidates, compresses, and moulds them into bricks of 
regular form and perfectly uniform dimensions, before he makes 
use of them. 
I will take the liberty of repeating here some reflections, 
no. iv. 2 L 
