200 NORTH SEA INVESTIGATIONS. 
point to some conclusion in which the theory of protection has no 
very obvious place. 
VIII. On some Specimens or Molva abyssorum, Nitss., From IceLanp 
AND Frog. 
The present note is a brief abstract of a paper read before the 
Zoological Society in May of the present year. The species was 
previously known only from the coast of Scandinavia, where it 
occurs chiefly at depths exceeding 100 fathoms, and appears to be 
known as the Birkelonge, or ‘Trade Ling.’’? I was able to show 
that it occurs regularly, if in rather small numbers, on the lining 
grounds off Faroe, and has also been taken, both by line and trawl, 
on the south coast of Iceland. 
The species may be described as differing from the common ling 
(M. vulgaris, Flem.) chiefly in characters which, in Gadoid fishes, 
have been found to be indifferently associated with either an 
abysmal or a boreal habitat. Thus the maximum size reached is 
smaller, the eye larger, the fin-rays more numerous, the body more 
slender and elongate, and the caudal peduncle very much more 
slender than in the common ling. ‘The visceral anatomy shows very 
well marked characters ; the liver is very large, and the walls of the 
alimentary canal extremely delicate—so much so, in fact, that it is 
difficult to lift the intestine, even in fresh specimens, without ruptur- 
ing it. Besides being more delicate, the intestine is also much 
shorter than that of the common ling, while the stomach is much 
larger. The comparative shortness of the intestine has been noted 
by Giinther in the case of a deep-sea member of the Percide, and a 
reduction in the thickness of the walls of this structure appears to 
be strictly comparable to the reduction noticeable in the bones and 
muscles of deep-sea fish generally. 
The air-bladders of the two species of ling do not differ materially, 
but the kidney of the deep-sea fish is less swollen in its posterior 
region than that of M. vulgaris. Moreover the so-called head- 
kidney in M. abyssorum is more definite in outline than the corre- 
sponding structure in the common ling, and was found to be typically 
reniform in structure and obviously functional. The head-kidney of 
the common ling, however, contains a certain amount of reniform 
matter, and cannot be regarded as wholly functionless. 
At the time my remarks were written, the only figure of 
M. abyssorum which I was able to discover was a small outline 
drawing given by Strém (Sond. Beskriv.), and I had therefore 
appended a larger and more detailed figure, adding another of the 
common species for purposes of comparison. However, before my 
