100 



Veutralerne ere korte, især hos de ældre, hvor de 

 udgjøre Vu ^^ Hoyedets Længde; de ere altid kortere, end 

 Øjets Læugdediameter. Hver af dem er indhyllet i en 

 tyk Hud, der gjør det unmligt uden ved Dissection at ad- 

 skille de enkelte Straaler; .disses Antal synes at være 2. 

 der begge ere kløvede til Granden (idetniindste er dette 

 Tilfældet hos de ældre). 



SkjælbeJdædning. Denne har hos L. frigidus en be- 

 tydelig Udbredelse, og har allerede hos foi-holdsvis unge 

 Individer opnaaet den storstc Del af sin Udvikling. Dog 

 optræde mindre, individuelle AtVigelser, idet enkelte mindre 

 Partier kunne være nøgne, som hos andre Ind. af samme 

 Størrelse ere skjælbekla'dte. Hos det største af de erholdte 

 Individer {p) har Skjælbeklædningen naaet sin største Ud- 

 bredelse; hos alle de øvrige ned til Indiv. a (med en To- 

 tallængde af 118"""). er den i det store tåget temmelig lige- 

 ligt udviklet. 



Det Tidspunkt, da Skjælbeklædningen begynder at 

 ud vikle sig hos Yngelen, synes at være. naar denne har 

 naaet en Længde af omtrent 50™'". Hos det mindste af 

 de erlioldte Yngel-Individer. hvis Totallængde er blot 37'""', 

 er Legemet endnu ganske nøgent; hos det noget støn-e 

 Individ, hvis Totallængde er 62'""'. ere Skjællene fremspi- 

 rende paa Legemets forreste Dele. medens Halen og Fin- 

 nerne endnu ere nøgne. 



Skjællene ere hos denne Art forholdsvis smaa og tæt- 

 stillede. De ere størst paa den forreste Del af Halen og 

 paa Legemets Sider; oj) imod Ryg- og Buglinieu blive de 

 betydeligt mindre, og ere særdeles smaa, hvor de optræde 

 paa selve Finnerne, ligesom di' blive mindre ud mod Hale- 

 spidsen. 



I sin fulde Udvikling er Legemet skjælbeklædt lige hen 

 til Hovedet, og paa Bagsiden lige hen mod Gruuden af 

 Ventralerne. Ligeledes er Skjælbeklædningen her tilstede 

 langs hele Grunden nærmest Dorsalen og Aualen, og stræk- 

 ker sig ud over disse Finner indtil henimod deres Midte, 

 længst paa Dorsalens mellemste Del, men ophører ganske 

 henimod Finnernes Slutning. Paa Hovedet kan aldrig oji- 

 dages Skjæl ; ligeledes ere Pectoraler og Ventraler altid 

 nøgne. 



Hos de ikke fuldvoxne Exemplarer er i Regelen Nak- 

 ken nøgen, ligesom Grunden langs Analen og Dorsalen, 

 tilligemed disse Finner selv. Dog have enkelte mindre 

 Individer ogsaa disse Partier skjælbeklfedte. ligesom de ud- 

 voxede. Bugen er hos enkelte af disse yngre Individer 

 fuldt skjælbeklædt, hos andre blot paa Siderne, ligesom 

 Skjællene langs dennes Midte kunne delvis eller fuldkommen 

 mangle. 



For at vise Skjælbeklædningens Varieren hos de for- 

 skjellige Individer, meddeles kortelig dennes Fordeling hos 



alle de hidtil erholdte Exemplarer. 



•« * 



1. Fuld Skjælbeklædning lige hen mod Hovedet og 

 paa Undersiden af Ventralerne; paa Finnerne er Grunden 

 af Dorsalen og Analen skjælbeklædt (A'. I, p). 



2. Fuld Skjælbeklædning, som foregaaende. men Skjæl- 

 beklædningen strækker sig ikke ud over Analen (/). 



The ventrals are short, particularly in the older ex- 

 amples, which have them one-ninth oi' the length of the 

 head ; they are invariably shorter than the longitudinal 

 diameter of the eye. Each of them is enveloped in a thick 

 cutaneous integiiment, dissection being necessary to disting- 

 uish the separate rays. The number would appear to be 2, 

 both cleft to the base (at least in the older specimens). 



Scales. — In L. frigidiis the scaled integument is 

 of considerable extent, and almost developed even in com- 

 paratively immature individuals. The scaling, however, can- 

 not be termed strictly constant, exhibiting as it does 

 minor individual dift'erences, some exam2)les having a few 

 small patches naked, which in others of the same size 

 are scaled. In the largest of the individuals obtained (p), 

 the scaled integument has attained its greatest development ; 

 in all the others, including specimen a, total length 118'""', 

 it is on the whole very nearly of uniform extent. 



The exact point of time at wliich the scales commence 

 developing in the fry. would apjjear to be, when they 

 have attained ;i length of about .")()"""• In the smallest of 

 the fry-specimens, total length only 37"""', the entire body is 

 as yet naked; in the other, somewhat larger individual, total 

 length 62 '"'", the scales have begun to appear on the anterior 

 parts of the body, whereas both the tail and the tins are 

 as yet naked. 



In this s])ecies. the scales are comparatively small, 

 and closely set ; the largest occur on the anterior portion 

 of the tail, and down the sides of the body ; near the 

 dorsal and ventral lines they diminish considerably in size, 

 being exceedingly small on the tins, and towards the tip 

 of the tail. 



When fully develoiied. tlie body is scaled up to the 

 head, and, on the under surface, uj) to the base of the ven- 

 trals. The scaled integument extends, too. along the whole 

 of the basal tract contiguous to the dorsal and anal, 

 reaching nearly to the middle of those fins; it is longest 

 on the middle of the dorsal, terminating near the extremity 

 of the said fins. On . the head, no scales can ever be 

 detected; the pectorals and ventrals, too, are both invari- 

 ably naked; 



In the specimens not quite full-grown, the nape 

 is as a rule scaleless. also the base of the body along the 

 dorsal and anal, and the entire surface of those fins. One 

 or two of the immature individuals, however, have these 

 pai'ts scaled, in common with the full-grown specimens. 

 The belly in one or two of these immature examples scaled 

 all over; in others, the sides only; the scales covering the 

 middle portion sometimes wanting, wholly or in part. 



The extent to which the scaling varies in tiie different 

 specimens will be Seen from the subjoined statement, briefly 

 showing the distribution of tlie scales in all the individuals 

 obtained. 



1. Fully scaled to the head, and, on the under sur- 

 face, within a short distance of the ventrals; the base of 

 dorsal and anal scaled (k, I, p). 



2. Fully scaled, as in the- foregoing specimens; the 

 scaled integument however not extending over the anal (_/'). 



