I"()Il!-I!K.\RIir.l) lidCKI.lNd. 



545 



30; Nir.ss., ^Shand. Fii., Fish:, p. 587; Gtiir, Vat. Brit. 



Mils., Fish., vol. IV, p. 3U7; Li.vdstr., Goll. Fish:, Goll. 



L. Hush. Sallsks. Arubcr. I8G(j, p. 21 (sop.); MoiiN, Ofvers. 



Vet.-Akad. Forli. 18(17, p. 2t!3; Coll., Forh. Vid. Selsk. 



Christ. 1874, TilhegBli., p. IIG; ibid. 1879, No. 1, p. 07; 



MAL.M, Gbfjs, lioh. Fn., p. 498; Wintii., Naturli. Tidskr. Kl.livn, 



sir. .'!, v(.l. \II, p. 33; Ltkn, Vid. Meddel. Nalurli. For. 



Kblivii 1881, p. 235; Day, Fish. Gt. Brit., frcl., vol. I. p. 



310, lab. LXXXIX, iig. 1; Joiin., Gilb. (Onos), Bull. U.S. 



Nat. Mu8., No. IG, p. 797; MOn., Hckk (.UoU'lla). Fi.irh. 



Osts., p. 83; Stokm, Norsk. Vid. Selsk. Skr. Tmiidbj. 1883, 



p. 3G; LiLL.i. (Onos), 6'v., Norg. Fish., vv\. II, p. 175; 



Hanskn, Zool. Dan., Fiskc, p. 85, tab. X, (ig. 5. 

 Gadus Mustela, Si'russenk., 1. c, p. 24, tab. II, Iig. li. 

 Motella caudacuta, Stor., I'roc. Bost. Soc. Nat. Hist., vol. Ill, 



p. 5; Mem. Aiiier. Acad. Artr., So., ii. ser., vol. VI, p. 361, 



tab. XXIX, fig. 1; Gill (Rhinoiiemus), Proc. Acad. Nat. Sc. 



Phihul. 18G3, p. 241. Cf. GooDK et Bean, Proc. U. S. 



Nat. Mils. vol. 3 (1878), p. 348. 

 Couchia Edwardii, Couch, Joiirii. Lin. Soc, Loud., Zool., vol. 



IX, p. 38. 



Ill Scandinavia, according to Lill.ikboijc, the Four- 

 Bearded Rocklin"' .sometimes attains a lenii'th of al)oiit 

 41 cm."; hut its usual Icnizth varies l)et\veen 20 and 

 38 cm. Tlie largest specimen ever talvcn on the coast 

 of Great Britain was 35 cm. long, according to Day. 

 In adult specimens the form of the body is compara- 

 tively elongated, this species being generalh- the most 

 slender of our Rocklings, and the depth at tlie begin- 

 ning of the anal fin measuring on an average only about 

 12 ?o of the leiigtli of the body. According to the rule 

 of the generic changes of growth, however, this pro- 

 l)ortion increases with age, after the Coiichia-stage, and 

 may sometimes be nearly as much as 14 ?o. The least 

 depth of the body, in front of the base of the caudal 

 tin, varies between 3',., and 4V2 %, or eventually nearlj' 

 5 %, of its length. Even in front too, the body is only 

 slightly terete. Tlie head is generally somewhat de- 

 pressed — all these remarks apply to adult specimens — 

 but its section is .sometimes nearly scpiare. At the ])e- 

 ginning of the second dorsal fin the thickness is about 

 V4 or ^5 of the depth; and posteriorly the thickness 

 decreases more and more, measuring at the beginning 

 of the anal firi al)out "3 or ' ., of the depth. The extreme 

 end of the tail is almost ribbon-shaped. The elongated 

 form of the bodv is further enhanced liy the comparatively 

 great Icnsth of the caudal fin, tiie middle rays of which 

 measure more than the poslorliital length of the head. 



The points in the form of the head that arc cha- 

 racteristic of this species, are the depth nf tlie snout, 

 the size of the eyes, and the comparative narrowness of 



the hc.id itself. With its tumid cheeks (thick mastica- 

 tory muscles) ;ind when the gill-covers are expanded, 

 tlic hiiid is broad anrl may be called depre.ssed; but, 

 until tiie fi.sh has attained a length of about 3 dm., the 

 breadth of the head is less than half its lenffth. The 

 (piadrilateral, more or less square form of the tran.sver.se 

 section of the head is persistent in the snout, at least 

 fill- a lengthy pei'iod, thuugh in old sjx'eiinens it iinall\- 

 becomes more depres.sed. Siniultaneou.slv with this 

 change of growth the position (jf tlic eyes is also altered. 

 Originally they are quite lateral, set vertically and pa- 

 rallel to (-ach other, but they eventually acquire a .somcv 

 what upturned position and diverge backwards. The tip 

 of the snout projects be>t)nd the upper lip and the still 

 shorter lower jaw, and the length of the snout is on an 

 average '/^ of that of the head. The eyes are oblong, 

 their longitudinal diameter measuring on an average 

 19V, ''i of the lenglh of the head. The nostrils are set 

 on the sides of the snout, on about a level with the 

 centre of the eye, the anterior pair rather near the be- 

 ginning of the sharply rounded ti]) of the .snout, the 

 posterior half-way between the tip of the snout and the 

 eyes. The barbel projecting behind each of the anterior 

 nostrils extends, when laid back, at least to the centre 

 of the eye and sometimes even a little behind the eve. 

 The unpaired barbel is the shortest, measuring oidv 

 about half the longitudinal diameter of the e\c. The 

 l)arbel under the chin is somewhat longer, but measures 

 less than the length of the eye. We must remember, 

 however, that during life these barbels, as well as the 

 fleshy lijis, are ver>" mobile, and the unpaired barbel is 

 said to be capable of elongation and retraction, like the 

 tentacles of a nmllusk. Tlie mouth is rather large, its 

 corners Iving in old specimens vertically below the hind 

 margin of the eves, ,iiid the maxillary bones extending 

 back to a distance from the tip of the snout that is 

 always more than half (about 53' » — G2 %) of the lengtii 

 of the head. The length of the lower jaw is always 

 less than this distance, and varies with age between 50 

 and about 59 % of the length of the head. Tiie ]>o.st- 

 orbital part of the head is generally longer than tiic 

 lower jaw. bur siiorter than the distance between the 

 tip of the snout ■•ind the hind extremity of the max- 

 illary bones. Its length seems to be more subject to 

 individual variations, and measures between 52' . and 

 57' J % of the length of the head. The gill-ojienings 



" WiNTllER mentions a specimen from Liim Fjord of a length of G3 cm. This statement is not contirmed, liowever, either by LCtke.n 

 or by Hansen, and is probably due to a slip of the pen or an error of the press. 



Scandinacian Fishes. *^' 



