Fig. 79—The Norwegian Deep-water Prawn (Pandalus borealis), Female. (After Sars.)

The second leg of the right side is indicated by dotted lines.

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A large species of Prawn is now imported to this country in considerable quantities from Norway. This is Pandalus borealis ([Fig. 79]), a species closely allied to the last-named, but differing in the longer and more slender rostrum and in many other characters, as well as in its larger size (specimens have been recorded of 6 inches in total length). It also differs in its habitat, for while P. montagui lives in shallow water, or even between tide-marks, P. borealis occurs at depths of 30 to 60 fathoms in the Norwegian fjords. The recent development of the fishery for P. borealis in Norway is a striking example of the practical value of zoological research. Until 1898 the species was hardly known except to zoologists, although a small fishery was carried on in the Drammen Fjord, near Christiania. The investigations of the naturalists employed by the Norwegian Department of Fisheries showed that the species existed in vast numbers in the deeper water of many of the fjords, and that it could be captured in abundance by means of a suitably-devised trawl-net. As a result, a very profitable fishery was established, and the "deep-water Prawns" are now not only largely consumed in Norway, but are exported in increasing quantities to the English and other markets.

In the warmer seas the large Prawns of the genus Penæus are of considerable importance. Thus, in the Mediterranean countries, Penæus caramote ([Plate IV].) is highly esteemed for food, and P. setifer and P. brasiliensis are largely consumed in the Southern United States. P. monodon and other species are eaten in India. An attempt has been made to send a species of the same genus (apparently P. indicus) in a frozen state from Queensland to the London market.

Numerous other species of Natantia are used for food in various parts of the world, but the only ones that need be further mentioned here are the River Prawns of the genus Palæmon, which are abundant in the fresh waters of most tropical countries, and sometimes grow to a very large size. They are generally distinguished by the fact that the legs of the second pair are very long, forming powerful pincer-claws. In the West Indies and Central America, P. jamaicensis ([Plate XXI].), which reaches a length of 10 inches exclusive of the great claws, is sold in the markets, while in India and elsewhere in the East P. carcinus, which grows to an even greater size, and other smaller species, are used for food. The fresh-water Prawns of the family Atyidæ, on account of their small size, are not of much importance from this point of view, but Professor Hickson states that the little Caridina nilotica, a very widely-distributed species, is eaten in Celebes.