642 



NATURAL HISTORY OF AQUATIC ANIMALS. 



snout, less conspicuous dorsal fins, darker coloration of the back, a more prominent and metallic 

 luster upon the sides, the clean white coloration of the belly, and the larger size of the eyes. I 

 propose to reproduce here the original descriptions and figures of Syrski, the discoverer of the 

 male Eel. 



Having met, writes Syrski, with many errors regarding the female organs of reproduction 



in the descriptions hitherto given of them, I intend to commence 

 by describing these organs, first with the view of rectifying and 

 completing the details, and also for the purpose of comparison 

 with the male organs. 



THE OVARIES OF THE EEL. The organs (Fig. 1) two in num- 

 ber, are ribbon-shaped, with leaflets on their outer face, and with 

 transverse folds. In the natural position of the live fish, the 

 one extends to the left and the other to the right of the aliment- 

 ary tube, following most of its angles nearly the whole length of 

 the abdominal cavity to the place where the dorsal parietes are 

 confluent with the lateral. 



The right ovary commences at a point nearly corresponding 

 to that where on the outside the right pectoral fin ends, and the 

 left ovary commences about two centimeters and ends three to 

 four centimeters behind the former. They extend three to six 

 centimeters back of the anus, into the caudal part of the animal's 

 body; they do not, however, unite in a single body, as some 

 have asserted, but both are toward the end inclosed in a perito- 

 neal membrane, and are separated from each other by the union 

 of these membranes, having each on their inner face an accessory 

 ovary (pars recurrens ovarii). , In rare cases is such an accessory 

 ovary wanting either on the right or on the left side. 



The ovaries in fully grown Eels are in the middle about two 

 centimeters larger, and posteriorly terminate in a thread-like 

 form. They are not smooth on both sides, but have, as was said 

 above, on their outer side numerous transverse folds (Fig. 2) full 

 of eggs (Fig. 3). 



It is another of Rathke's erroneous assertions, likewise main- 

 tained by others, that the genital opening through which the 

 eggs pass out from the abdominal cavity is formed by two holes, 

 a right one and a left one. I have invariably found in all speci- 

 mens examined a simple hole, which communicates with the right 

 and left half of the abdominal cavity by means of a transverse 

 fissure between the straight intestine and the urinary bladder 

 (Jumura recto-vesicalis) and opens in the urethra (Fig. 4). 



It is generally admitted that the eggs, when loosened from 

 the ovaries, fall indiscriminately into the abdominal cavity, but it 

 is not said which way they take in order to go out through the 

 genital aperture. As I have invariably found that the fully developed ovaries lean with their outer 

 surface against the side of the abdominal cavity, and approach with their free edges the lower 

 lortioii of this side, forming, so to speak, a furrow, I must conclude that the loosened eggs 



I-* 



Fin. l.-Ftmatr Eel, lonffitndiiuil uelion of the 

 filnitijnfn; natural rizf. 



a. Ki<:ht ovary. 



b. Left ovary. 



e. \ rri'ftnory part of right oviry. 

 d. I,rfl lUTrHMiry part. 

 Dividing membrane. 

 /- A nnl <! jn fKNinn . 

 a. Vrinarv bladder. 

 h. Kat on I lie right nidc. erroneonnly 

 taken for the testicle* by Home. 

 A'. Similar fat covering the stomach. 

 i. Kat "ii the left aide. 

 Jr. Stomach. 

 I 1 ' . Iciiui. 

 m. Liver, 

 n Kall-bladder. 

 o.o. Pectoral Una. 



