XXll - INTRODUCTION. 



are much more simple, consisting, as will be found towards 

 the season of producing their young, of two elongated oval 

 lobes of roe, one on each side of the body, placed between 

 the ribs and the intestinal canal ; these lobes, in the female 

 called hard roe, contain a very large number of roundish 

 grains called ova or eggs, which are enclosed in a delicate 

 membranous tunic or bag, reaching to the side of the anal 

 aperture, where an elongated fissure permits egress at the 

 proper time. In the males, the lobes of roe are smaller than 

 in the females, and have the appearance of two elongated 

 masses of fat, which are called soft roe ; they remain, how- 

 ever, firm till the actual season of spawning, when they be- 

 come by degrees more and more fluid, and the whole is ulti- 

 mately voided by small portions at a time under slight ab- 

 dominal pressure. 



A few exceptions to this rule appear to exist ; but Avhich 

 may perhaps rather be considered malformation than natural 

 structure. According to Cavolini and Cuvier, some species of 

 the genus Serranus have each lobe of roe made up of a por- 

 tion of hard and of soft roe, and these fishes have been con- 

 sidered as hermaphrodites, each fish capable of producing 

 fertile ova without the assistance of a second fish. Among 

 other accidental malformations may be included the appear- 

 ance of a hard or female roe on one side, and a soft or 

 male roe on the other side of the same fish. This has 

 been observed occasionally in the Perch, Mackerel, Carp, 

 Cod, Whiting, and Sole ; and the probability is, that in 

 these cases the fishes are prolific alone, since the two 

 lobes of roe are observed to be of equal growth, advanc- 

 ing to maturity together. Pallas believed that in the ge- 

 nus Syngnathus there were no males ; but the singular 

 anomaly of both sexes being found to carry ova, the females 

 in the abdomen, and the males for a time in their caudal 



