30 



Forekomst os; LeTCvis. 



Den her omhandlede mærkelige Dyreform fore- 

 kommer ikke sjelden langs vor hele Kyst, fra Chri- 

 stianiafjorden til Vadsø, men synes idethele at op- 

 træde baade hyppigst og kraftigst udviklet i vor 

 arktiske Region. I stor Mængde har jeg saaledes 

 fundet den paa en Plads i Lofoten, Brettesnæs, hvor 

 mange hundrede Individer indsamledes i Løbet af et 

 Par Dage, og ogsaa ved Finmarken har jeg paa sine 

 Steder trnffet den i mængdevis. Den pleier at holde 

 til paa maadeligt Dyb, fra 10 til 30 Favne, og helst 

 paa saadanne Steder, hvor Bunden er dækket af 

 forraadnende Tangarter, hvoraf den for en væsent- 

 lig Del synes at ernære sig. Ligesom Tilfældet er 

 med flere andre Crustaceer, synes Hannerne kun til 

 visse bestemte Tider af Aaret at opnaa fuld Slægts- 

 modenhed, og optræder da kun ganske enkeltvis. Der- 

 imod er endnu ikke slægtsmodent udviklede Hanner 

 at finde til enhver Tid af Aaret og næsten i samme 

 Antal som Hunnerne. I Maaden at bevæge sig paa, 

 ligesom i sin hele ydre Habitus, har dette Dyr en 

 umiskjendelig Lighed med en colossal Copepode; 

 navnlig er den habituelle Overensstemmelse med 

 visse Harpacticider meget paafaldende. Ligesom hos 

 disse .sidste, er Legemet overordentlig bøieligt, navn- 

 lig i dorsal Retning, og kan ofte krummes saa stærkt, 

 at Halegreneue kommer i Contact med Pandepladen. 

 Bevægelsen sker stødvis ved kraftige og temmelig 

 rythmiske Slag af Svommefødderne, hvorved Lege- 

 met drives frem med temmelig betydelig Fart. De 

 slægtsmodne Hanner er overotdentlig raske i sine 

 Bevægelser og foretager ofte længere Udflugter i 

 Våndet. Derimod holder Hunnerne og de endnii ikke 

 fuldt udviklede Hanner sig i Regelen ved Bunden 

 og bevæger sig her mellem Bundmaterialet, ialmin- 

 delighed paa Siden. De forstaar herunder med stor 

 Behændighed at skjule sig mellem Mudret eller de 

 hensmuldrende Tangrester, som bedækker samme, 

 saa det slet ikke er saa let at finde dem freni, trods 

 den ikke ubetydelige Støn-else. Lettest opdager 

 man dem ved at slaa det optagne Bundmateriale ud 

 i et fladt Kar, med en nbetydelig Kvantitet af Sjø- 

 vand. De tilstedeværende Exemplarer vil da, især 

 naar man rører lidt om i Bundsatsen, snart vise sig 

 paa Overfladen af Våndet, og da de i Lighed med 

 forskjellige andre Crustaceer ikke formaar at komme 

 ned i Våndet igjen, efterat de først er komne i Be- 

 rorelse med Luften, kan de med Lethed opsarales i 

 levende Tilstand. Bringer man et helst yngre In- 

 divid i en passende Kvantitet Sjøvand under Mikro- 

 skopet, kan man saa noiere studere de forskjellige 

 Livsytringer og kan gjennem de halvt gjennemsigtige 

 Integumenter observere Hjertets Pulsationer, Tar- 

 mens perestaltiske Bevægelser og Branchialfoddernes 

 Spil. Di.sse sid.ste, der ingensomhelst Inllydelse bar 

 paa Locomotionen, vil man i Regelen finde i en 



Distrilmtiou and Labits. 



The remarkable animal form spoken of here 

 appears not rarely along our entire coast, from the 

 Christianiafiord to Vadso, but seems, on the whole, 

 to appear most frequently, and most powerfully de- 

 veloped in our Arctic region. I have thus fonnd it 

 in great abundance at a place, Brettesnæs in Lo- 

 foten, where many hundreds of individuals were col- 

 lected in the course of a couple of days; and also 

 in Finmark I have, in certain places, met with it 

 in great abundance. It is accustomed to keep itself 

 at a moderate depth, from 10 to 30 fathoms, and 

 preferably in those places where the bottom is co- 

 vered with decomposing sea-weed of which it appears, 

 to a material extent, to nourish itself. Like what 

 is the case with several other Crustaceans, the males 

 appear to only attain full power of reproduction at 

 certain fixed seasons of the year, and are then met 

 with only quite solitary. On the other hand, not 

 fully reproductively ripe developed males are to be 

 found at all seasons of the year, and almost in 

 equal number to the females. In manner of 

 movement, as well as in entire extei'nal habitus 

 this animal has an unmistakable likeness to a 

 colossal Copepod, especially is the habitual agree- 

 ment with certain Harpacticidæ very striking. Like 

 as in those last, the body is extraordinarily fiexible, 

 especially in dorsal direction, and may ofen be so 

 strongly bent that the caudal branches come into 

 contact with tiie frontal plate. The movement takes 

 place in jerks, with powerful and tolerably ryth- 

 mical strokes of the swimming feet, by which the 

 body is drawn forwards with pretty considerable 

 speed. The reproductively ripe males are extra- 

 ordinarily active in their movements, and frequently 

 make long excursions in the water. On the other 

 hand, the females and the not yet fully developed 

 males remain, as a rule, at the bottom, and move 

 here among the material of the bottom, generally 

 on the side. In doing this they understand to con- 

 ceal themselve.s with great dexterity in the mud, or 

 the decomposing remains of sea-weed which covers 

 it, so that it is not at all easy to search them out, 

 in spite of the not inconsiderable size. We find 

 them easiest by pouring the collected bottom mate- 

 rial into a flat vessel, along with an inconsiderable 

 quantity of sea-water. The specimens present will 

 then, especially if the bottom stufi" is stirred a little 

 up, soon show themselves on the surface of the 

 water, and as they, like several other Crustaceans, 

 are unable to swim downwards in the water again 

 after they have first come into contact with the air, 

 they may with ease be collected in the live state. 

 If we place, ]n'eferably a young individual, in a 

 suitable ijuantity of sea-water, under the microscope, 

 we can then more closely study the various features 



