34 
J. BADCOCK-ON MELICEBTA RINGENS. 
greater magnifying power. It is attached to a branch of Nitella or 
a filament of an Alga. The water is just a drop—hardly that. Yet, 
if not injured, it still maintains its ordinary occupation—still works 
and feeds. By and bye you exert a little more pressure—the house 
is injured, and our friend, more alarmed than usual, makes its 
escape. Its term of life is soon to end, as it becomes quite helpless 
out of its house; so a little more pressure may he exerted in order 
that its mechanism may be more fully seen and understood. 
Examining the Melicerta with a tolerably high power, and under 
pressure, our attention is attracted by the apparent rushing of 
divergent streams through a very complicated piece of machinery, 
and very careful observation becomes necessary if we would follow 
these streams to their several destinations. 
Let us try to understand them, and in order to do this we must 
get some idea of the mechanism now at work. There are the four 
expanded lobes or petals, on the margins of which is a continuous 
double-grooved row of fine hairs—a collecting apparatus, which, 
when set in motion, resembles a continuous or endless chain, 
and this is the most striking and beautiful characteristic of the 
animal. The cilia, vibrating with quivering life, lash the water 
in opposite directions, and gather up the floating decomposing 
vegetable matter in a whirling current, which they then pass along 
the chase or groove on to the mouth and sorting organs. The 
streams are here united, hut only to be subjected to a thorough 
hut rapid investigation, which results in their being again divided, 
and this time into three streams or currents. That which is good 
for food is selected and flows onwards to the mastax, there to he 
ground down by the action of the teeth into a finely-triturated 
material for the nourishment of the body; another stream flows 
off with building-material to the pellet-organ or pug-mill for the 
making of bricks; and the refuse is swept off with vigour at a 
tangent out into the open water. Thus five or six streams or 
currents are going on at the same time—all separate and distinct; 
for the inward currents are not stopped while the subsequent divi¬ 
sion which separates them is going on, and at the same time the 
creature is feeding, making bricks, and building up its habitation. 
At intervals it has to get rid of effete matter, which involves 
another action apparently requiring more than ordinary calculation 
or volition. I shall have presently to revert more particularly to 
this; meanwhile let us examine more minutely the several organs 
concerned in the other operations. 
We have got thus far a pretty clear idea of the rushing and 
apparently opposing currents which at first sight seemed so con¬ 
fusing, and now let us follow them one by one. When their 
division takes place, one current is carried aside to the pug-mill 
laden with material for brick-making. This may be demonstrated, 
but not very easily, by placing a little carmine or other non- 
deleterious colouring substance in the water, when it will readily 
be accepted apparently both as food and also as a new material for 
bricks; and we may possibly be able to trace it as some portion 
