THE INTERNATIONAL FISHERIES EXHIBITION. 237 



found in our seas, some in large quantities, and they are consumed 

 by fish and other marine animals. There are also in this group 

 the Jelly-fishes, Medusae, which, during the summer and autumn 

 months, are found floating in the ocean around our coasts, and 

 occasionally, under their umbrella-like discs, young fish have 

 been observed to obtain refuge from the pursuit of their enemies. 



Corals among the Actinozoa in many ways hold a most im- 

 portant place, while their hard structures are exceedingly diversi- 

 fied and interesting. Commercial forms are principally obtained 

 from the Mediterranean, the Red Sea, Persian and Arabian Gulfs, 

 the Mauritius, the Islands of the Malay Archipelago, Japan, &c. ; 

 while the reef-constructing species are distributed, and can only 

 exist where the mean temperature of the sea is not below 66°. 

 The coral reefs are classed as forming Fringing Reefs, Barrier 

 Reefs, and Atolls. These reefs are largely frequented by fish, 

 some of which possess most gorgeous colours, but in many 

 instances it has been observed that the flesh of those obtained 

 from such localities is frequently poisonous. 



Among the jointed Annuloida the term Entozoa has been 

 frequently used for the purpose of designating internal parasites. 

 Epizoa, on the other hand, is the term employed for certain 

 small crustaceans, which, in their adult stage, are likewise para- 

 sitic upon the exterior of fish ; they possess a suctorial mouth 

 and limbs furnished with hooks, suckers, or bristles. 



Mollusca, or soft-bodied animals, commonly known as shell- 

 fish, constitute a most important class in the economy of fisheries, 

 not merely in their providing adult fish with food, but also, as 

 some of them breed at the same period of the year, their eggs 

 and microscopic young are useful as aliment to the fish-fry. Some 

 forms are likewise more directly employed by man as food and 

 bait, as Oysters, Mussels, Cockles, and Periwinkles. The con- 

 sumer needs no reminder as to how scarce the first have become ; 

 and along the east coast of Scotland Mussels for use as bait are 

 attaining famine prices, while the belief appears to be almost 

 general that there Mussel fisheries are retrograding. Many other 

 forms of molluscs are much employed by line-fishermen for bait, 

 especially Whelks, Squids, Cuttle-fishes, &c. 



Among the marine Echinoderms, viz., Sea-urchins, Star-fishes, 

 and the Sea-cucumbers, Holothuriidce, all assist more or less in 

 providing food for fish, while a species of the last is largely 



