G. GENERAL NATURAL HISTORY AND ZOOLOGY. 211 



shell becomes decomposed. On this Ticcount the flesh of the 

 herring, after feeding upon these mollusks, soon becomes 

 tainted by their decomposition, and gives out a disagreeable 

 smell, notwithstanding the application of salt. 



It may be asked why the summer and autumnal herring 

 feed upon this food, and not the spring herring nor those 

 taken in the open sea, both the latter being capable of pres- 

 ervation without any detention in the nets. The reason of 

 this seems to be that the spring and open-sea herring are cap- 

 tured when under the stimulus of the spawning season, and 

 in the search for a suitable place for the development of their 

 young. At this time the question of food is reduced to zero, 

 or near it, and a careful examination of the stomachs of herring 

 taken under such circumstances shows comparatively little 

 animal matter. Summer and autumnal herring, on the other 

 hand, are specially engaged in seeking for food and bringing 

 up their flesh, and that at a time when the larvse of the lower 

 animals are found swimming freely about in large quantity 

 upon the surface of the sea. Die JVcitur, 1869, xlvii., xlviii. 



PHOSPHORESCENCE OF DEAD FISH. 



According to Panceri, the phosphorescent substance in dead 

 fish is of a fatty character, and due to slow oxidation in con- 

 tact with air. Phosphorescence generally, it is said, shows 

 itself some time after death, and continues until putrefaction 

 commences. As soon as a true decomposition sets in, accom- 

 panied by the disengagement of ammonia, phosphorescence 

 ceases, while it is prevented by the presence of fresh water, 

 alcohol, or carbolic acid, but is facilitated by oxygen. 12 A, 

 Aug. 10, 287. 



FISHES OF CUBA. 



A recent number of the Annals of the New York Lyceum 

 of Natural History contains an elaborate paper, by Professor 

 Poey, the well-known naturalist of Havana, upon the genera 

 of the percoid fishes found in, the West Indian seas, especially 

 in the waters around Cuba. 



FRESH-WATER FISHES OF ALGERIA. 



In a communication by Colonel Play fair upon the "Hydro- 

 graphical System and the Fresh-water Fish of Algeria," he 



