COMMON LING. 
527 
20 — 23 % of the length of the body — partly by the 
greater breadth of the interorbital space — more than 
30 %, sometimes, in very large Ling, as much as 46 %, 
of the distance between the tip of the snout and the 
hind extremity of the maxillary bones — partly by the 
smaller eyes — with a longitudinal diameter of about 
22 — 11 % of the length of the head or 65 — 33 % of 
the length of the snout in specimens between 23 and 
164 cm. long — and partly by the longer barbel under 
the chin, measuring more than the longitudinal diameter 
of the eyes. The occiput and the forehead are flatter 
than in the preceding species. The length of the lower 
jaw is as a rule somewhat less than the postorbital 
length of the head, which is about 10 V 2 — 13 % of the 
length of the body. The tip of the snout generally 
projects beyond the lower jaw, but, as in the preceding 
species, the case is sometimes reversed, and a form with 
this characteristic is described by Nilsson under the 
name of Molua raptor. The teeth and gill-covers are 
like those of Molua dipterygia , but in old Ling the 
sinus in the lower posterior margin of the operculum 
is to a great extent filled up. 
The first dorsal fin is distinguished from that of 
Molua dipterygia not only by the number of the rays, 
which is generally greater, but also by its more elongated 
form, the upper margin in young specimens being di- 
stinctly rounded and highest in the last third of its 
length, but in old specimens fairly straight (of uniform 
height). In adult specimens the rule holds good that 
the base of the fin is more than twice its height. The 
distance between the fin and the tip of the snout varies 
between 27 and 30 %, the length of its base between 
10 and 13 %, and its height between 5 and 6 %, of 
the length of the body. In young Ling only the pos- 
terior rays (with the exception of the last one) are 
branched, but in most old specimens, on the other hand, 
only the first three rays and the last ray are simple. 
The second dorsal fin is considerably longer and 
contains a greater number of rays, but is of a similar 
structure. It begins just behind the first dorsal fin, 
the distance between it and the tip of the snout vary- 
ing between about 38 and 43 % of the length of the 
body. Its length varies between 45 (sometimes 43) and 
47 V 2 %, and its greatest height (in the posterior part) 
between 6 ! / 2 (sometimes 7) and 5 %, of the length of 
the body. Behind the middle of its length there is 
only a slight diminution in its height. 
In this species too, the anal fin repeats the form 
and structure of the second dorsal, though it is shorter 
and lower. The distance between it and the tip of the 
snout, which varies between about 45 1 / 2 and 53 % of 
the length of the body, is always greater than its length, 
which varies between about 40 and 34 % of the length 
of the body. It ends a little in front of the perpen- 
dicular from the termination of the second dorsal fin. 
Its greatest height is about 6 — 5 % of the length of 
the body. 
The caudal fin is much more rounded than in 
Molua dipterygia , but in specimens of equal size its 
length is about the same. 
The pectoral and ventral fins are of essentially the 
same form and structure as in Molua dipterygia, but 
are usually shorter. The length of the former is always 
less than the postorbital length of the head; and the 
length of the latter, which in young specimens is much 
greater, diminishes so rapidly during growth that in 
specimens about 4 dm. long it is somewhat less than 
the postorbital length of the head, and in specimens 
16 dm. long not even half of this length. The position 
of the ventral tins also varies considerably with age, 
in accordance with the general rule among the Teleosts, 
moving farther and farther forward during the normal 
period of growth. In Ling about 23 cm. long the 
distance between these fins and the tip of the snout is 
about 1 9 1 / 2 % of the length of the body, in specimens 
between 40 and 50 cm. long about 1 8 1 / 2 %, and in 
specimens 55 cm. long about 1 7 1 2 %. In very old 
specimens, however, of a length of 164 cm. for example, 
we may find a reversion to the juvenile characters, 
this percentage having again risen to 21 or 22 %. 
The scales resemble those of Molua dipterygia, but 
are relatively still smaller and, together with the nu- 
cleus, more oblong and of more uniform breadth. They 
are rectangular and twice or three times as long as 
broad, with very gradually rounded corners. 
M’ In tosii has investigated and described a the chan- 
ges of growth during the embryonic stages of the Ling, 
as well as during its larval and postlarval stages. The 
systematic interest of the last of these periods of growth 
is especially great. At the age of 3 or 4 months, at 
a The Life-history of a Marine Foocl-fisli, Roy. Inst. Gt. Brit., Febr. 1, 1889. On the development and life histones of the teleostean 
food and other fishes, By W. C. M’Intosh and E. E. Prince, Trans. Roy. Soc. Edinburgh, vol. XXXV, part. Ill, p. 827. 
