198 MARKETABLE BRITISH MARINE FISHES 



made into cakes. I have found these young eels on the shore 

 under stones in Plymouth Sound in February and later. They 

 are 2 to 4 inches long, and extremely transparent, except 

 for a black line inside the body along the spinal cord. There is 

 no difficulty in understanding how fresh water streams and 

 ponds are abundantly supplied with eels from the multitudes of 

 young which ascend from the sea. 



It must be well understood that these young eels, elvers or 

 eel fare, although very transparent and having no pigment and 

 probably no scales in the skin, are otherwise fully developed, 

 and have the fins and other characters of the adults. But 

 before they reach this condition they pass like other fishes 

 through a transformation which is not yet fully known. 



In the course of their interesting researches upon the Lepto- 

 cepJiali, Grassi and Calandruccio have convinced themselves that 

 one of these forms, previously known as a distinct kind, is the 

 larva of the common eel, as the Morris is the larva of the conger. 

 The form in question, named LeptocepJialus brevirostris, or the 

 short-snouted LeptocepJialus, is rather small, not exceeding 3^ 

 inches in length, and \ inch in vertical breadth. The Sicilian 

 naturalists have not been able to follow the entire transformation 

 on one and the same specimen, but in several individuals kept in 

 confinement they have seen the most important changes, and have 

 traced in a number of specimens a complete series of steps from 

 the LeptocepJialus to the young transparent eel. The reduction 

 in length during the change may be more or less in different indi- 

 viduals, but it does not exceed f inch, so that the smallest 

 perfect eels are 2 inches long. The investigators convinced 

 themselves that young eels with the characters of the adult have 

 never been found less than 2 inches long, so that there is no 

 evidence to contradict their conclusions. But it is a strange 

 fact that the particular LeptocepJialus which they connect with 

 the eel has never yet been found except in the channel between 

 Sicily and the mainland. The only conclusion to be drawn is 

 that the LeptocepJiali escape capture on account of their powers 

 of concealment. It remains for British naturalists to discover 

 these larvae in British waters. 



It seems at first sight probable that the elvers which ascend 

 rivers in spring are the offspring of the parents which descend 

 the previous autumn. But considering the case of the conger. 



