COMMON LING. 



527 



20 — -23 % of the length uf the bod) partly by the 



greater breadth of the interorbital space — more than 

 30 %, sometimes, in very large Ling, as much as 46 %, 

 (if the distance between the tip of the snout and the 

 liind 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 G.") — 33 % of 

 the length of the snout in specimens between 23 and 

 164 cm. long — and partly liy 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 lOV, — 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 \\\x\\ 

 this characteristic is described bv Xilssox under the 

 name of Mohia raptoy. The teeth and gill-covers are 

 like those of Molua diptenjgia, 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 diptenjgia 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- 

 stincth' 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 

 l:)etween 27 and 30 %, the length of its base between 

 10 and 13 %, and its height between 5 and 6 %, of 

 the length of the bodv. In young Ling only the pos- 

 terior ravs (with the exception of the last one) are 

 branched, but in most old specimens, on the other hand, 

 onh" the first three raA's 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 l:)etween about 38 and 43 % of the length of the 

 body. Its length varies between 4.5 (sometimes 43) and 

 47' 2 %> and its greatest height (in the posterior part) 

 between 6' ^ (sometimes 7) and 5 %, of the length of i 



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 forin 

 and structure of the second dorsal, though it is shorter 

 and lower. The distance between it and the tip of the 

 snout, Avhich varies between al)out A^^^l^ and .53 % of 

 the length of tlie Ixidy, is always greater than its length, 

 which varies between about 40 and 34 % of the lengtii 

 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 mucli more I'ounded than in 

 3Iolua dipteri/ffia, 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 usuallv sliorter. 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 fins also varies considerably with age, 

 in accordance with the general rule among the Teleosts, 

 moving farther and farther forAvard 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 19\ ?■& of the length of the body, in specimens 

 between 40 and .50 cm. long about 18'/o %, and in 

 specimens 5.5 cm. long about 17\ %. 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 ?6. 



The scales resemble those of Molua dipterygta, but 

 are relativelv 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'Intosh has investigated and described" 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 



« Tlie Life-histor,/ of a Marine Food-fsh, Roy. Inst. Gt. Brit.. Febr. 1, 1889. On the decelopment and life histories of the teleostean 

 food and other fshr.,. By W. C. M'Intosh md E. E. Prince, Trans. Roy. Soc. E-linbureli. vol. XXXV. part. III. p. 827. 



