The Crustacea which form this order differ much more from each other than those which are arranged in the last order, and consequently we find among them some very singular in their outward formation. Few of the species appear to be used as food by mankind, but they constitute a great portion of the nourishment of fishes and other inhabitants of the water. They are at times used by fishermen as bait. Many of them are very minute, and form most excellent objects for the microscope. They have been divided into several sections, according to their outward form; but as so little is known of their habits, we shall confine ourselves to a description of some of the best known.
The Spotted Squill, ([Squilla maculata].)
The Squill seems to form a connecting link between the last and present order. It is the only genus of the heterobranchial Crustacea in which the eyes are placed on footstalks; the head, instead of being distinct, appears in a great measure drawn into the corslet. It has been called the Sea Mantis, from its bearing some resemblance to an insect of that name, on account of the singularly-formed hooks with which two of its foot-jaws are armed.
The species shown in the engraving is found in the Indian Seas; it is the largest of the genus.
The shell with which these creatures are covered has very little consistence, more resembling hardened skin than shell. They frequent the sandy bottom of the sea.
Squilla maculata.
There is a small species which is found in fresh water, in which the young, after the eggs are hatched, remain for some time in shelter under the plates with which the body of the mother is covered.