“These little crustaceous animals may be found at all seasons of the year, near the surface of the water; they are, however, most abundant in July and August. I have collected great numbers of them on a warm day in the latter month, with a small cloth net, immersing it about an inch below the surface. They are mostly colourless in ponds covered with herbage, but in small collections of rain water, on a loamy soil, are of a fine rich colour.
“The body of this creature is covered with crustaceous or shelly plates, which overlap each other, and admit both of a lateral and vertical motion between them. Their ends do not meet on the side, but have sufficient space between them for the insertion and play of the organs of respiration. The rostrum, or beak, is short and pointed: it is a prolongation of the first segment which forms the head. A little above the beak, a single eye is imbedded beneath the shell, of a dark crimson colour, nearly approaching to blackness. The true form of this organ it is difficult to determine. Mr. Baker gives it the shape of two kidney-beans placed parallel to each other, and united at their lowest extremities. When viewed laterally, it appears round, while in some other positions it is square.”
The eggs are curiously placed in two bags, presenting an appearance similar to clusters of grapes, and of considerable magnitude, compared with the size of the animal. These egg-bags are seen in the engraving, (which represents a female,) projecting from each side of the hinder portion of the shell. The centre of each egg is of a deep opaque colour, which in some specimens is green, in others red.
The young of the Cyclops, when first excluded from the egg, are extremely minute, and so different from the mother, that Müller has described them as forming two distinct genera.
The Small Water Flea, ([Cyclops minutus].)
This species of the Water Flea differs from the last, in having its body divided into a greater number of segments; it is also much smaller; it is equally active with that last described, but its form renders it more graceful in its motions. “These little creatures,” says Mr. Pritchard, “seem to possess great discernment and cunning; for, if approached, they remain motionless on the plant on which they reside, in the apparent hope that they may be overlooked; but when a fit opportunity occurs, they suddenly bend the body, and spring away with a kind of vaulting leap.”
Cyclops minutus, much magnified.
They inhabit the various species of confervæ, and may often be met with in great numbers on the stalks and underside of healthy duckweed, growing on the surface of the water. They are most numerous in April and May, and disappear as the heat of the season increases. They will not live in stagnant water containing much decomposed vegetation, and require, therefore, to be kept for observation in a large vessel of clean water. They are easily caught after a shower of rain, on the under surface of the duckweed, by taking out a little with a basin or cloth net. When found, they appear busily engaged in search of prey, moving about with great activity, and examining every portion of the plant in the most scrutinizing manner. In this pursuit the body is not bent as in the magnified representation in the engraving, but is kept in a straight crawling position. Their natural length is about the three hundredth part of an inch.