OVARIES (.>P THE EEL. 



643 



descend between the abdominal partition and the folds and leaflets of the ovary in the above-men- 

 tioned furrow, and from it pass to the genital aperture without scattering in the abdominal cavity. 



Fig. 2 Piece of the onary, twice its natiiral size, with 



ovarian leafiets arranged in transversal rows, 

 on its surface. 

 The shorter border attached to the dorsal wall 

 of the abdominal cavity ; the longer being 

 free. 



Fig. 3. —Piece of a somewhat developed ovary, one hun- 

 dred times the natural size, shi'Wivg the trans- 

 parent eggs with the gerrninative vesicles and 

 the gerrninative dots. 



As to the development which the ovaries undergo, I have observed from the end of ISTovember 

 till the beginning of March, in many adult Eels, of the length of 530 millimeters and more, that 



the ovaries were of the breadth of fifteen to twenty-five 

 millimeters, and of a yellowish and sometimes reddish- 

 white color, produced by the development of adipose tissues 

 and of the blood-vessels and not by the eggs filled with 

 little globules of fat; the genital aperture and the fissura 

 recto-vesicalis were open. 



In other Eels, of a length sometimes of 600 millimeters 

 and more, I found the ovaries less broad, with but little fat, 

 mG.i.—AnaipartofafemMUEei,twicethenaturaisize. and of a mucous and almost glassv appearance, so that I 



a. straight intestine. o .; r-i 7 



c.' ujtaaiy wadder.^'"''^'^' could disccrn the so-callcd vesicles and germinative dots 



e'. Pa"tHion. {nuclei and nucleoli) ; the genital aperture and the fissura 



f. Urogenital opening. • 7 . i j 



g. Outlet of the genital opening in the urethra. reCtO-VeSlCdhS Were ClOSCd. 



The ovaries of young Eels, of the length of about 500 millimeters, contained invariably 

 but little fat, and the eggs were without globules. The gradual growth and enlargement of 

 the ovaries go on simultaneously with the opening of the genital orifice. According to the quan- 

 tity of fat contained in the ovaries, they have a mucous and glassy, or more or less opaque or 

 white, appearance, or have small shining dots. From the end of March till October I found in the 

 majority of Eels which I examined, measuring 600 to 700 millimeters in length, that the ovaries 

 were scarcely white, and that the genital aperture was closed. The number of eggs contained in 

 both developed ovaries reaches, according to my calculation, five millions. The larger eggs 

 measured by me had a diameter of one-fourth to one-fifth millimeter, while tlie eggs of an adult 

 'Grongo' {Conger) had, according to my measurements, a diameter of one-third of a millimeter, 

 and those of the 'Murena' {Murcena helena) almost one millimeter, which explains to me why the 

 ovaries of the two last-mentioned species of fish have long since become known. 



In an Eel measuring 590 millimeters, examined on the 6th July, the left ovary was entirely 

 wanting, and replaced by a mass of fat. 



The spermatic organs. — The position of these organs (Fig. 5), which are not ribbon- 

 shaped like the ovaries, but represent two longitudinal rows, each with about fifty lobules (Fig. 6), 

 of the width at most of three millimeters, and found only in Eels not more than 430 milli- 

 meters long, corresponds entirely with that of the ovaries. In these organs are likewise found 



