FISHES.
We shall take the torpedo and the carp as examples of the two chief divi sions of the class, as we did in speaking of the male organs.
In the former fish there are two uteri, communicating with the cloaca by means of a common vagina. The oviducts form one infundibulum, which receives the ova as they sucessively arrive at maturity. These are very large in comparison with those of the bony fishes. The yolk, in its passage through the oviduct, acquires its albumen and shell. The latter is of a horny consistence, and is known by the name of the sea-mouse. It has au elongated quadrangular figure, and its four corners are curved and pointed in the skate, while they form horny plaited eminences in the sharks. The secretion of the albumen, and the formation of the shell, are performed by the papillous in ternal surface of the duct ; and chiefly by two glandular swellings which appear towards its anterior extremity in the summer months, while the eggs are be ing laid.
The structure is much more simple in the carp, and probably also in the other oviparous bony fishes. The two roes oc cupy the same position as the soft roe of the male does. They are placed at the side of the intestines, liver, and swimming bladder, as far as the anus. They consist of a delicate membrane inclosing the ova, which arc all of one size, and extremely numerous (more than 200,000 in the carp ); and terminate by a common opening be hind the anus.
The immense number of ova contained in the ovaria of fishes accounts to us sa tisfactorily for the astonishing multitudes in which some species are formed. In a perch weighing one pound two ounces, there were 69,216 ova in the ovarium ; in a mackarel of one•pound three ounces, 129,200 ; in a carp of eighteen inches, Pe tit found 342,144; and in a sturgeon of one hundred and sixty pounds, there was the enormous number of 1,467,500.