THE EEL FAMILY. 459 



to be done. The first step in the progress was made by 

 Delage's discovery of the transformation of Leptocephalus 

 morrisii into a young conger, and the obvious conclusion there- 

 from was that the common eel had also a leptocephaline stage. 



Grassi and Calandruccio have pointed out the particular 

 form (Z. brevirostris), and, in addition, have been enabled to 

 confirm and extend the observations of Delage upon the lepto- 

 cephaline stages of the conger. Whilst according due merit to 

 the able researches of these two naturalists, we consider that 

 the other points with respect to the development of the eel are 

 not yet proved. 



The eggs described by Raffaele, with vesicular yolk (a 

 character found in some clupeoids) and a large perivitelline 

 space (a feature shared by the eggs of the pilchard and the 

 long-rough dab) and the larvse hatched therefrom, have yet to 

 be proved to be those of mursenoids. They appear to be 

 perfectly normal pelagic eggs with surface-habitat, and give no 

 indication of ' floating at a great depth.' 



We still require definite answers to the following : — 



1. When and where do eels and congers normally spawn ? 



2. Does the reproductive act involve immediate death to 

 the parent ? 



3. What are the appearance and structure of the eggs of 

 the conger and the eel ? 



4. Are they pelagic or demersal ? If the former, are they 

 of surface- or deep-sea habitat ? 



5. What is the normal habitat of the Leptocephali, at least 

 L. brevirostris and L. morrisiil Why are they not found in 

 abundance on our coasts ? 



6. Do abnormal Leptocephali occur, or, indeed, is a lepto- 

 cephaline stage a normal part of the muraenoid life-history 

 at all? 



It may be that the complete memoir promised by the Italian 

 naturalists may clear up some of these points and may convert 

 hypotheses with varying degrees of probability into ascertained 



