90 Thirty-second Report on the State Museum. 



ceans, and their accidental accumulation in certain places favorable to the 

 fisheries. During some years, the sea, near the western coast of Norway, 

 throughout the whole summer, has been filled with great masses of different 

 crustaceans. At such time the fishermen expect to be favored with the pres- 

 ence on their coast of the ; ' herring-mountain " — a high, deep, and closely- 

 packed mass of herrings. 



The shad (Alausa sapidissima) eagerly devours crustaceans when they can 

 be obtained. During their presence in our rivers for the purpose of spawning, 

 they partake of no food. A microscopic examination of the stomachs of twenty 

 shad (Alausa vulgaris of Europe), made at their advent into fresh water, 

 revealed the tarsi, antennae, etc., of microscopic Entomostraceans and other 

 small crustaceans. Nothing else could be recognized. 



The white-fish ( Corregonus albus) was for a long time believed to feed on 

 algae and aquatic plants ; but it was ascertained by Dr. Hoy, of Racine, Wis., 

 through a careful examination of the partially digested contents of their stomachs, 

 that they fed mainly on a small crustacean, whose presence in the lake had not been 

 suspected.* 



Similar examinations, instituted by Mr. J. W. Milner, of the stomachs of 

 white-fish from various localities in Lake Michigan, confirmed the statement of 

 Dr. Hoy, that the Crustacea constituted by far the larger proportion of their 

 food, namely, species of the Gfammaridw and 3fysidce. Associated with these 

 were Molluscan species of Pisidium and other genera, together with Phryganid 

 insects. At Sault Sainte Marie the white-fish has been taken with a hook 

 baited with a May-fly. 



The favorite food of the black bass (Micropterus nigricans) is the craw-fish — 

 species of Cawbarus and Astacus, when they can be procured. 



The lake-herring (Argyrosomus clupeiformis) feeds upon the Gammaridce 

 and insects. 



Mr. Seth Grreen informs me, that it is believed that the peculiar richness of 

 the Otsego lake bass (Corregonus $ Otsego) — its superiority over that of the 

 white-fish of the lakes, of which it is thought, by many, to be but a local variety, 

 is the result of its feeding largely on a small crustacean, which is remarkably 

 abundant in Otsego lake. 



The food of the salmon (Salmo salar), previous to its entering fresh water 

 for spawning, during which period, like the shad, it partakes of no food, consists 

 principally of Crustacea, " this rich aliment giving the color and flavor for 

 which its flesh is so highly prized." 



The American smelt (Osmerus mordax) — one of the salmon family — feeds 

 largely on the shrimp. They are readily taken with a hook, baited with any of 

 the smaller crustaceans, or pieces of the larger species. 



Nearly all our salt-water fishes feed upon crustaceans, from the minute Ento- . 

 mostraca to the large crabs and lobster. Prof. Verrill, loc. cit., pp. 514-521, 

 gives a list of thirty-two species, in the stomachs of which crustaceans, as the 

 principal portion of their food, were found. 



* My sis relicta Loven. The detection of this species in the waters of lakes Michigan and Supe- 

 rior was a very interesting discovery, not only from its first having been brought to notice in 

 this country, in the stomach of a white-fish, but also from its identity with the species previously 

 known as existing, under similar conditions, in the fresh-water lakes of Sweden and Norway. 

 Dr. Sars had found it in Wener and Wetter, and eight other lakes in Sweden, and in one lake 

 in Norway. Dr. S. regards it as specifically identical with the salt-water form occurring off the 

 coasts of Labrador and Greenland— My sis oculata ; the varietal differences which he finds, he 

 regards as resulting from the interruption of its former salt-water communication. He accord- 

 ingly designates it as M. oculata, var. relicta. — (Smith's Fresh-water Crustacea of the United 

 States ; U. S. Comm. of Fish and Fisheries, pt. ii, for 1872-73.) 



