4 R. COLLETT. M.-N. Kl. 



For the first, it is possible that L. gracilis has already been de- 

 scribed under some other name ; and there are to hand two such forms, 

 both infantile (like the type specimen of L. gracilis), and exhibiting 

 insufficient specific characteristics to allow of their being properly defined, 

 viz., L. perspicillum, Kr. 1844, from Greenland, and L. rossi, Malmgr. 

 1864 from Spitsbergen. 



In the second place, the specimens to hand, obtained from Scandi- 

 navian waters, although fully capable of propagation, do, possibly, not 

 represent the extreme limit of development that this species can attain 

 to, and L. gracilis may, possibly, reach a greater size, and then be of 

 different appearance to the above mentioned individuals from our shores. 



It is possible that one may at last rediscover it in some or other 

 previously recognised form (from Greenland) whose youthful stages have, 

 hitherto, been unknown. 



Scarcely sufficient materials have come to hand as yet, to allow of 

 a final settlement of these questions. 



As it is presumed that every contribution to the knowledge of this 

 remarkable genus (of which hardly one of the many described species 

 can, as yet, be said to be known in its entirity) will be of interest, 

 I have endeavoured to describe that, which at present, must be regarded 

 as certain facts connected with the Scandinavian form of this species, 

 the typical «Z^. gracilis^' \ and, in the present treatise, I have treated 

 the species as if other doubtful synonyms did not exist. In the following 

 pages I shall mainly endeavour to point out the changes undergone by 

 L. gracilis during its growth, from infancy up to the time when the 

 power of propagation has commenced. 



As above mentioned, the materials to hand have been principally 

 obtained during trawling operations olT the south coast of Norway, in 

 the Cattegat and Skagerak, which were undertaken with a practical 

 scientific object in view, under the leadership of Dr. Petersen and 

 Dr. Hiort, and by these gentlemen kindly placed at my disposal. 



From my investigations it appears, that the transverse bands down 

 the body, on which the original characteristics arc mainly based, arc 

 chiefly representative of youth, and wholly or almost disappear in the 

 somewhat older fish. As similar markings are probably found on several 

 species of Lycodes only during youth, it is clear that satisfactory 

 specific characteristics can hardly be obtained within this genus, except 

 from more matured specimens. 



