FISHES 149 



and shift for themselves. In the pipe-fishes the male 

 has a pouch, consisting of membranous folds, under 

 the tail or under the abdomen for receiving the eggs 

 from the female. The eggs are fertilized and neatly 

 placed in rows in the pouch where they remain until 

 hatched. The majority of fishes, however, prepare 

 no nests and leave the eggs to their fate after they 

 are laid. 



The number and size of the eggs produced vary 

 greatly. They are fewest in those species in which 

 they are fertilized and hatched internally, and in 

 general they are fewer in those species which pro- 

 duce large eggs than in those which produce small 

 ones. In some of the species, as for example the cod, 

 one female may have several millions of eggs during 

 a single spawning period, whereas the red salmon, 

 which produces comparatively large eggs, probably 

 rarely has more than about three thousand. 



Many marine species produce floating eggs; 

 others have demersal eggs. The floating eggs gen- 

 erally are single. Occasionally, however, they occur 

 in gelatinous masses. The eggs of the goose-fish, for 

 example, are enveloped in a gelatinous, floating veil, 

 often measuring over a yard in width and eight to 

 ten yards in length. The demersal eggs, also, may be 

 laid singly or in masses. Some species deposit their 

 spawn on a sandy or gravelly bottom, and others seek 

 vegetation. The silversides, for example, deposits its 

 eggs among vegetation to which they adhere by 

 means of gelatinous threads. 



Some of the skates lay eggs which have horny 

 shells and are more or less rectangular in shape with 



