i8o SALT-WATER FISHES 



1892, two eminent Italian biologists, Drs. Grassi and Calan- 

 druccio, made a series of important investigations of different 

 Leptocephali taken in the deep water near Messina, and 

 identified them as the larvae of the conger, fresh-water eel, 

 and other murasnoids. 



These Leptocephali, little transparent eel-like forms, have 

 long been known, though never taken in abundance, on our 

 own shores, and the one which eventually becomes a conger has 

 been named after Morris, who first described it. The Morris, 

 though previously considered a distinct species, was regarded 

 as the young of the conger, on the assertion of an American 

 naturalist, in the early sixties, and Dr. Giinther dissented from 

 this view * only so far as to regard it as an abnormal condition 

 of the larva in a state of arrested development. This opinion 

 was based on the fact that he had seen small, perfectly developed 

 congers with the adult characters smaller than the largest 

 Leptocephali, and he therefore concluded that there could be 

 no sequence. A later explanation, however, shows that the 

 larval conger abstains from nourishment at this stage of its 

 career, and consequently shrinks on being transformed to the 

 perfect form, a condition with analogies in other animals. 



If the credit of having first suspected the Morris to be 

 a larval conger belongs to an American, that of first identifying 

 the male conger to a German, that of watching the actual trans- 

 formation of the Morris into the conger to a Frenchman, and 

 that of having traced the larval form and metamorphosis of the eel 

 to Italians, few naturalists have studied the conger in captivity 

 more closely and carefully than Mr. Cunningham at Plymouth ; 

 and he has propounded one theory which, if open to argument, 

 is at any rate as interesting as any of the rest. His view, 

 briefly, is that the conger spawns once and then dies. This, 

 as we have seen, is also thought to be the truth of one of 

 the gobies, though it is not with the conger a case of 

 coming to maturity, breeding, and dying all within one year. 

 * Introduction to the Study of Fishes, p. 673. 



