Fig. 210.—The Common Shrimp (Crangon vulgaris)
The Common Shrimp (Crangon vulgaris) is an exception, however, for it may be distinguished when boiled by its dull greyish brown colour. When alive this species is of a very pale greenish or greyish tint, lightly spotted with brown; and its habits are so interesting that it will well repay one to watch it either in the aquarium or in a rock pool. It frequents sandy coasts, and can hide itself very quickly by burying its body in the sand, using for this purpose both its legs and its antennæ.
The Prawn frequents rocky coasts, where it may often be obtained in large numbers by sweeping with a suitable net under the cover of weeds and stones. Its body is of an exceedingly pale greenish colour, and so transparent that it is quite inconspicuous when in the water. Prawns are turned to a rose-red colour by boiling, and they are captured in large numbers when young and sold as ‘red shrimps.’
Fig. 211.—The Prawn (Palæmon serratus)
In addition to the common species mentioned there are quite a number of shrimps and prawns to be found in our seas, but some of them inhabit deep water and are rarely to be found between the tide-marks. All, however, are eagerly devoured by fishes, and, on that account, are often to be obtained in good condition by examining the contents of the stomachs of freshly caught fishes. In fact, this mode of search for the smaller species of deep-sea life is not to be despised, for it is a means by which we can obtain specimens that are not often secured by the methods coming within the ordinary range of the amateur’s work.
It will be remembered that we spoke of the Decapods as consisting of two main groups—the Great-tailed (Macrura) and the Short-tailed (Brachyura). Frequently, however, we find the order divided into three sub-orders as follows:—