538 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [14] 



nified 50 times. These crustaceans are the best food for herrings and 

 sprats. By feeding on them theybecome fatter and get a better flavor 

 than from any other food. Whenever herrings feed on these crusta- 

 ceans their excrements have a reddish color; when they eat many small 

 worms they are yellowish, and of a dark color when the herrings feed 

 chiefly on floating snails or mussels. In the abdominal cavity of fully 

 grown herrings the sexual organs, the ovaria, and spermaries take up 

 the largest room (Fig. VIII). As soon as the eggs and milt are fully 



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 s - 5 



Fig. VII. — A male crustacean (Temora Ion- 

 gicornis), from the Bay of Kiel, magnified 

 50 times. Below it is given in its natural 

 size. 



Natural size. 



Fig. IX. — A spermatozoan 

 (from the milt) oftheherring, 

 magnified 375 times. 



e>- 



FlG. X.— Herring 

 eggs, natural size 

 (from the Schlei), 

 sticking to Pota- 

 mogeton pectina- 

 tus. 



■a o| matured they pass from their en- 

 S"i £ velopes through a narrow tube 

 = EiT toward an opening which is im- 

 mediately back of the anus (Fig. 

 VIII, F). In spawning the milt- 

 ers swim by the side of the spawn- 

 ers and emit their milt. Whilst 

 om the eggs, after having been emit- 

 ted, sink down in the water, the fine thread-like particles, spermatozoa, of 

 which the milt is composed (Fig. IX), enter the eggs and cause the devel- 

 opment of the little fish from the egg to commence. As soon as the eggs 

 of the herring meet with plants or touch the bottom they adhere by means 

 of a sticky substance which covers them (Fig. X). Between the two sexual 

 organs lies the intestinal canal (Fig. VIII and Fig. XI, A). It starts from 



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