FISHES. 877 



tliey are merely held in the ovaries by a pedicle. It is in this situ- 

 ation that they increase in size, and the germ, contained in them, is 

 developed, as that of an oviparous fish, is developed in water. 



The two ovarian sacs generally unite in a common canal, which 

 has its outlet behind the anus, and before the urinary orifice. It is 

 the same with those of the testicles. 



Very frequently this outlet is only a simijlc hole, but has a pro- 

 truding portion in the form of a slip, which then exists in both sexes, 

 and always that it may be subservient to their congress ; for it is 

 observed especially in the genera which have many viparous species, 

 as the blennies, gobies, &c. 



In certain fishes, as the eel and the lampieys, the ovaries divide 

 externilly into a great number of lobes of different figures, kept 

 together by a common meml)rane, and containing eggs in their folds : 

 these are not sacs, but resemble heaps of piled leaflets. 



They are without a canal, and tlie eggs can only escape by 

 falling into the abdomen, and leaving it by one of the two holes 

 inerced on the sides of the anus. This is what is known to exist, 

 particularly in the lampreys*, and what we are also obliged to 

 believe of the eel. 



It has equally been advanced of the troutsf , of which it is true, 

 that the ovaries are closed, on the side of the abdominal cavity, by the 

 peritoneum, that glues them to the region of the spine, and as they 

 are internally divided into transverse laminae, without there being 

 seen any outlet for the eggs, that which is taken for the oviduct, ap- 

 parently reduced to a simple ligament. 



The number of eggs, in the fertile species, is sometimes frightful ; 

 in more species than one, it exceeds a himdred thousand. 



Now and then we find amongst the ordinary fislies, individuals which 

 have, on one side an ovarv,and on the other a testicle, and Avhich are 

 consequently true hermaphrodites ; but it appears that certain species 

 naturally and constantly unite the organs of both sexes. Cavolina 

 asserts this of the acanthopterygians, the sea perch; and Sir Everard 

 Home, the eel and lampreys ; with regard to the last, M. M. Ma- 

 gendie and Desmoulins, think that the males are infinitely less nume- 

 rous than the females :|; ; but the solitary example which they produced 

 may be only a female void of eggs, or whose eggs by some cause, 

 were not developed. As to the sea-perch Ave have ascertained that 

 the posterior portion of their ovaries, is of a very different tissue 

 from the rest of their mass, and very like that of a milt. It remains to 

 be proved, whether this part really performs its functions. 



The rays, the squalus, and the chimera have their organ, more 

 complicated. The testicles of the ray, placed at the top of the abdo- 

 men upon the stomach, (or behind it, supposing the fish to be erect 



* Carus Lootomie, p. 6.37. 



-f- Dumeril, upon Cyclestome fishes, p. 53. 



X These anatomists have observed a lamprey, which, although it was caught at 

 the time when all the others were full of eggs, had, it is true, organs placed and 

 divided like ovaries, but whose leaflets contained no eggs, and only appeared to offer 

 a very fine tissue ; but by means of the microscope, globes similar to those which 

 contained the ovaiies of the sturgeon in their faded state were perceived. 



