No, 26.] ARTHROSTRACA OF CONNECTICUT. II 



ECONOMIC IMPORTANCE. 



Except for a few species which destroy submerged timbers, 

 the economic importance of the Arthrostraca is indefinite but 

 probably great on account of their large numbers and their 

 widely extended habitat. Many species perform an important 

 service as scavengers by destroying decaying matter along the 

 shore. According to Miss Richardson, certain parts of the 

 coast of France, where shark-fishing is carried on extensively, 

 would be almost uninhabitable were it not for the swarms of 

 Isopoda which consume the heads of the sharks which are 

 thrown back on the beach and which would otherwise become 

 highly offensive. Naturalists in the Arctic regions, where the 

 Amphipoda are especially numerous, obtain thoroughly cleaned 

 skeletons of bears and other animals by .exposing their bodies 

 alongside of their boats to the shoals of small Amphipoda, 

 which pick them absolutely clean. According to Mr. Geoffrey 

 Smith in the Cambridge Natural History, Amphipoda, "when 

 crowded sufficiently, will even attack living fishes, and by 

 sheer press of numbers impede their escape and devour them 

 alive." It is hardly possible, however, that any appreciable 

 number of fish are so destroyed. 



The Amphipod, Chelura terebrans, and the Isopod, Limno- 

 ria lignonim, often occurring together as well as with the " ship- 

 worm," Teredo, do great damage by destroying submerged tim- 

 bers. Chelura is quite abundant on the European coast and has 

 been reported from Bermuda, but on the Atlantic coast of New 

 England it has been reported only from Woods Hole and Prov- 

 incetown, Massachusetts. At the latter place. Professor Verrill 

 found it from 8 to 12 feet below low water. (Smith, Proc. U. S. 

 Nat. Mus., vol 2, p. 232, 1879.) 



Along the Connecticut shores Limnoria is the most important 

 crustacean which destroys timbers. Verrill, in the Report on 

 the Invertebrates of Vineyard Sound (p. 379), describes it as 

 eating burrows into solid wood to the depth of about half an 

 inch. These burrows may be so numerous that the outer layers 

 of the timbers decay rapidly and are washed away readily by 

 the waves, leaving a new surface which in turn is attacked by 

 the crustacean. It works chiefly in the softer parts of the wood 

 between the hard annual layers and avoids knots and those 



