608 



SCANDINAVIAN KISIIICS. 



ovdiiiMi'A' mediolitteral line — in a siiu'lit curve down- 

 wards to tile middle of tlie side, or even down to tlie 

 anal region and then along the base of the anal fin. 



the othei a dorsal line — iisualh- witli larger Imt 



more scattered pores and seldom extending farther than 

 to a line with the \ent or a little behind it. Sometimes 



perceptibly more than half (at le:i>t 't') %) of tlie distance ' from e;ich temporal region, one — corresj)onding to the 

 l)etweeii the anal tin and the latter. 



The changes caused by age in the <()loi'ation of 

 fjiji'Diles are extraordinarily great. All the fry — with 

 the exception of one species — are adorned with a hand- 

 some, regular marking (see for exam])le figs. 14S and 

 150) of selliform. dark-margined spots across the dorsal 

 tin and the back. On the hindmost part of the tail \ again a ventral branch starts from the antei"ior part of 

 these spots are generally prolonged downwards, forming the inediolateral line, its structure being the same as 

 transvers(! bands across the dorsal tin, the bod\', and that of the latter. I.L'iken, whi) was the first" to draw 

 the anal tin. The spaces between the spots grow lighter attention to all these differences, based upon them a, 

 and lighter, being sometimes milk-white on the dorsal I .system of determining the species within the genus; 

 tin and the back, and the same light colour sometimes | but GCnther has pointed out' the systematic ditticulties 

 appears in the form of an ocellated spot within one or involved in a strict adherence to characters derived 

 another of the selliform spots. With age, however, from this relation, characters wliicli at different ages 

 these selliform spots coalesce below, and the boundary 

 between them and the coloration of the rest of the 

 body is effaced, being sometimes replaced by a net- 

 work of darker colour, starting from the original dark- 

 coloured inai-gin of the spots. These changes of colo- 

 ration are also common to other kindi'ed genera within 

 the family, and strongly remind us of the distribution 

 of the spots in the l'>el|iouts, in all its irregularity. 



The dentition of the palatine bones and of the head 



and in different individuals show variations, the cause 

 of wdiich is as yet ludiuown, and which also in many 

 cases defy ol).servation. Glxthek jiasses tlie same judg- 

 ment upon the characters which hav(» been drawn from 

 the extent of the scales in these fishes. 



Ever since Richardson described his Li/codcs nni- 

 cosKs from Northumberland .Sound', we have known 

 that scales may be wanting ■within this genus in indi- 

 viduals u]i to a length of •2<S cm. In 11S74'' Bleekei! 

 of the vomer in Lijcodes — a character which is wanting founded the genus Li/rai/alc/iis to emphasise this cha- 

 in the Eelpouts — is here counterbalanced by a nega.- racter, wliich. according to Bean"', may be jiersistent 

 five t'haracter, the absence of transverse palatal folds I in the sjiecies just mentioned even at a length of 4;^> 

 behind the rows of teeth in the jaws. Tlie nostrils are ' cm. However, to the best of our judgment and with 

 simple and tubular in this genus also, but the snout | the knowledge we now possess of the changes of growth 

 is more elongated and of a looser structure, this being | and sexual differences within the genus, this s])ecies 

 due to the still greater development of the ca\ities be- I can scarcely be distinguished, except perhaps as a local 

 longing to the cephalic^ system f)f the lateral line. The i variet^•, from Lifcodes Tunicri, the foi'in descriln'(l by 

 extension of this system over the body is singular i Bean' and TtHiNEi;" from Alaska, or from the form 

 enough. No less than three lateral lines may appear i brought home by the \'ega Expedition* from the en- 

 on each side of the body — but, as fai- as we know, trance of Chatanga Bay (Siberia, E. of Cape Tschelju- 

 no more than two in the same individual. These lines ' skin). The latter form is in ;dl probaliility identical 

 are generally wanting in A'oung s])ecimens and are again i with the form subsecjuently described \>\ LitivEN' under 

 effaced in old. In most cases two lateral lines start I Coei.eit's name of Lycodos Ijltkenii, which (tCntiiek 



marked 



a..isnl nnd 



■ilicilnter.-il lino 



" Vid. Meddel. Naturli. For. Kblivn 1879—80, |.. ?.29. Kuoyer, liowever, liad nlready 

 his Lycodps perspkillnm (Natiirh. Tidskr. Kblivn, ser. Ill, vol. I, (1862), p. 292). 



' Deep Sea Fish., Chall. Exped., ]>. 79. 



■■ The Last of the Arctic Voyages, vol. II, p. :)(i2. 



'' Vcrsl., Med. Akad. Wet. Amster., 2 K., 8 Del. ]>. .309. 



' Bnll. U. S. Nat. Miis., No. 15, p. It.",. 



/ Proe. U. S. Nat. Miis., vol. I, p. 463. 



'-' Cnnti-ih. \nt. Hist. Alaska, Arct. Ser. I'ubl. Sign. Serv. U. S. Army, No. II, p. 9:^. PI. 



'' Gr. Intern. Fiaher. E.xliib. London 1883, Swed. Catal., p. 176. 



' Kara-Havets Fiske, Dijmphna-Togtets Zool.-bot. Udb., p. 14, Tab. XVI. In tlie lar.t;- 

 considerably greater nmnber (13 — 15) of palatine teeth than in Lijcoites mttcosns (7, both according to Richardson's figure and in the speci 

 men from Cliatanga Cay). P>iit the great reserahlanee in otlier respects between these nominal species forces ns (o (lie eoncUision that tlii 

 difference is individual and may depend on circumstances of age or sex, unless indeed it belongs to a local variety. 



nf (he.se specimens LOtke.n remarked a 



