22 2 SOUTHWELL: REPRODUCTION OF THE EEL. 



(3) ' The river eels have their settled spawning places in the sea. 

 These are mud banks, which the eels visit in large numbers for the 

 purpose of spawning. The young fry develop on these banks, and go 

 to the liiouths of the rivers in the beginning of spring, about eight or 

 ten weeks after their birth.' 



(4) ' The old eels, both males and females, die soon after the 

 spawning season. The extraordinarily rapid development of their 

 organs of generation exhausts them to such a degree that they die 

 soon after having spawned. This is the reason why they are never 

 seen to return.' 



The subsequent discovery by Dr. Otto Hermes of the mature 

 sexual organs in the male Conger tended to confirm the investigations 

 of Drs. Syrski and Jacoby. On the 20th June, 1879, ^ Conger eel, 

 one of a number kept by Dr. Hermes in an aquarium, died, and was 

 examined by him on the same day ; to his surprise he found its 

 sexual organs entirely different from those he had hitherto observed 

 in eels, and upon an incision being made in them a quantity of milky 

 fluid oozed out, which, upon being placed under the microscope and 

 magnified 450 times, showed a large number of live spermatozoids, 

 whose head and tail could easily be distinguished, and which moved 

 about in a very lively manner, thus fully establishing the fact that the 

 organs examined by him were those of the male fish. 



The sexual organs in both male and female Congers are similarly 

 placed, and generally resemble those of the river eel, the chief 

 difference in that of the male Conger being that the lobes into which 

 it is divided are larger and less numerous in proportion than the 

 corresponding divisions in the same organ in the river eel ; the male 

 of the Conger, also, like the same sex in the river eel, is found to be 

 considerably smaller than the adult female. 



Such is the present state of our knowledge with regard to this, in 

 some points, still obscure question ; the direction in which farther 

 investigation should be pursued, seeing how hopeless it appears to 

 follow the eel in its journey to the sea, would seem to be by bringing 

 the sea to the eel, and thus artificially producing the conditions under 

 which its spawn is believed to be matured. This might possibly be 

 accomplished by placing migrating eels in an aquarium and 

 judiciously substituting sea-water in lieu of that from the river. The 

 experiment is certainly worthy of a trial by those who have the 

 opportunity, and should it prove successful, the reproach that 

 modern science with all her aids and appliances has been unable to 

 clear away the mystery which surrounds the propagation of the eel 

 would speedily be removed. 



Naturalist, 



