456 THE EEL FAMILY. 



that it comprised a number of young stages of other species, 

 but it was left to the American ichthyologist, Gill, upon 

 evidence derived from a comparison of the anatomical resem- 

 blances between the two, to definitely formulate the suggestion 

 that Leptocephalus morrisii was the larval form of the conger. 



A Leptocephalus (probably a young conger) in the St 

 Andrews University Museum, caught in 1869 on the western 

 coast, has been figured here (PI. XIX, fig. 6) to show the 

 appearance of this interesting little form, and the description of 

 another, caught in June 1890, in Loch Scridain, is as follows: — 

 ' Young conger, 80 mm. In this the lateral line has a row of 

 black chromatophores of the ordinary structure from behind the 

 pectorals to the tail, ventrally a double row (somewhat widely 

 separated), of black chromatophores to the commencement of 

 the anal fin, where the rows approach each other, and have 

 between them a median row at the base of the fin. The dorsal 

 comes far forward, reaching within | in. of the tip of the 

 snout, but still far behind the tip of the pectorals. No black 

 pigment-specks occur at the base of this fin. Both anal and 

 dorsal fins have permanent rays. The tail resembles that 

 of the adult. The gill-slits are almost ventral. The eye is 

 larger than in the common eel of the same size, and the shape 

 of the body different^' 



Six years after Gill's discovery, viz. in 1870, his theory was 

 accepted by Dr Gtinther, the celebrated ichthyologist^ but 

 with a very peculiar modification. In his Catalogue of Fishes 

 (British Museum) he puts forward the hypothesis that the lep- 

 tocephaline stage is not a normal larval (or more accurately 

 post-larval) conger but is arrested in its development at an 

 early stage, so that it increases in bulk and continues to 

 develop in some particulars whilst other organs remain in 

 a rudimentary condition. Under these circumstances, he 

 supposed that the Leptocephalus was incapiable of transfor- 

 mation into a conger. If, he suggests, the normal young 

 conger is nursed in a littoral environment then very young 

 stages carried out by accident to the open sea and submitted to 



' W. C. M. 9th S. F. B. Report, p. 336. 



^ To whom one of us gave his collection of Leptocephali in 1868. 



