OUTLINES OF ICHTHYOLOGY. 163 



the male the lobes of roe are smaller than in the 

 female, and present the appearance of whitish fat ; 

 they remain firm until the actual spawning-season 

 when they become gradually fluid, and are ulti- 

 mately voided in small portions at a time on the 

 abdomen of the fish being slightly pressed. 



At the spawning-time, which differs in almost 

 every species, the fish repair some to the gravelly 

 shallows or weedy banks of rivers and others to 

 the sandy bays of the sea. This is sometimes 

 called " going to hill," or " roading." The female 

 then deposits her eggs, in portions at a time, and 

 the male presses his milt out over them ; and 

 without this impregnation, no vivification, or hatch- 

 ing, can take place ; the eggs could never arrive 

 at maturity. 



A few unimportant exceptions to this rule exist. 

 According to Cuvier, some species of the genus 

 Serramis have each lobe of roe made up half of 

 hard and half of soft roe, and these have been 

 considered as being capable of producing fertile 

 eggs without the assistance of a second fish. This 

 may, however, be very possibly considered as a 

 malformation rather than a natural structure. 

 Perch, Mackerel, Carp, Cod, and some others, 

 have been occasionally found with a lobe of soft 

 roe on one side, and a lobe of hard roe on the 

 other ; and in these cases it is probable that the 

 fish are prolific alone. 



The female fish is in some instances attended 



