56 



af Hunkjon, sker der en end yderligere Reduktion 

 af disse Følere, hvorved de antager det for Hunnen 

 charaeteristiske Udseende af 2 simple triangulære 

 Flige. Hos Hannen omformes Ydergrenen til (Irihe- 

 kloen, og Indergrenen persisterer som det lille knude- 

 formige Fremspring ved Enden af Basaldeleu, inden- 

 denfor Kloens Udspring. 



Forekomst og Levevis. 



Nærværende Phjdlopode synes at forekomme 

 meget almindelig, i Øst-Finmarken, hvor jeg har 

 tåget den paa flere Steder i stor Mængde ; saaledes 

 i et lidet grundt Tjern ved Mehavn, hvor den fand- 

 tes sammen med FoJyartcnna forcipata, i et lignende 

 Tjern ved Vardø, og i flere Smaatjern og grunde 

 Danune paa Fastlandet Øst af Vardø. Af Prof. 

 Lilljeborg er den desuden tåget ved Nordkap. I 

 Vest-Finmarken har jeg deriraod ikke oliserveret 

 den, ligesaalidt som nogetsteds i Nordland. Mærke- 

 ligt nok optræder den igjen langt .sydligere i Lan- 

 det, nemlig paa Dovres Høideplateau, hvor jeg har 

 tåget den meget almindelig i grunde Damme saavel 

 ved Kongsvold som ved Jerkin. Denne iscderede 

 Forekomst saa langt Syd jiaa kan kun forklares 

 ])aa den Maade, at nærværende Phyllojiode før i 

 Tiden, da Kliniatet var mere arlctiskt, har været 

 udbredt over liele vort Lund, ogsaa i Lavlandet, 

 men derjiaa, etterhvert som Klimatet forandrede sig, 

 liar trukket sig tilbage nordpaa og tillige til Hoide- 

 plateauerne, hvor de klimati.ske Forhold mere lig- 

 nede de oprindelige ; med andre Ord : den er her Syd 

 i Landet at betragte som en saakaldt «relict^ Form, 

 en Levning fra den arktiske Fauna, der for i Tiden 

 var udbredt over vort hele Land. 



Da de Smaatjern og Damme, hvori den lever, 

 regelmæssigt udtorres mod Slutningen af Sommeren, 

 (ig væsentlig kun skylder sin Tilbliven Snesmeltnin- 

 gen paa Forsommeren, er denne Forms Levetid kun 

 indskrænket til nogle faa Maaneder af Aaret. I 

 Lobet af forholdsvis kort Tid liar den imidlertid 

 gjennemgaaet sin Udvikling, og deretter gaar For- 

 plantningen hurtigt for sig. De i Ægsækken inde- 

 holdte Æg, bliver, som anfort, altid omgivne med en 

 meget tyk Skal og er aabenliart alle beregnede paa 

 at overvintre, for til den følgende Sommer at ud- 

 vikle sig til en ny Generation. Arten er saaledes 

 for hvert Aar ki;n re])ræsenteret ved en enkelt Ge- 

 nei'ation. Æggene atsættes i Mudret paa Bunden 

 af Dammen, og da denne Afsætning afÆg foregaar 

 gjentagne (i ange af livert Hunindivid, vil der snart 

 opliolte sig en anseelig Mængde af Æg, der vil sikre 

 Artens Tilværelse paa de Steder, der er gunstige 

 for dens Trivsel. Det er 1'orst ved Midsommertid, 



with n(j bristles whatever. If the young one is 

 destined to be of the female sex, a .still further re- 

 duction of these antennæ takes ]dace, whereb}' the}'- 

 assume the appearance, charactei'istic of the females, 

 of 2 simple triangular flaps. In the male the outer 

 ramus is transformed into a jjrehensile claw, while 

 the inner ramus becomes the small nodiform pro- 

 jection at the end of the basal part, inside tlie root 

 (if the claw. 



Occurence and Habits. 



The present Phyllo])od seems to occur verv ge- 

 nerally in East Finmark, where I liave found it in 

 many places in great numbers, for instance, in a 

 little, shallow lake at Mehavn, where it was found 

 together with Fohiarfcutia foycipafa : in a similar 

 lake at Vardo, and in several small lakes and 

 shallow ponds on the mainland east of Vardo. It 

 has also been found by Prof. Lilljeborg at the North 

 Cape. In West Finmark, on the other hand, I have 

 not observed it, nor yet anywhere in Nordland. 

 Curiously enough, it appears again much farther 

 south, namely on the liigh plateau of the Dovre 

 Mountains, where I found it very plentiful in sbal- 

 low ponds both at Kongsvold and Jerkin. This 

 isolated occuri'ence so far south can only be ac- 

 counted for by the supposition that formerly, when 

 the climate was more arctic, this Phyllopod was 

 distributed over the whole of our land (Norway), 

 lowlands as well as highlands, but that, as the cli- 

 mate changed, they have withdrawn to the north 

 and the high plateaus, where the climatic conditions 

 more resemble those originally prevailing; in other 

 words, here in the south of the country, it must be 

 regarded as a so-called ^relict» form, a vestige of 

 the arctic fauna which was formerly distributed 

 over the whole country. 



As the small lakes and ponds in which it lives 

 dry up jieriodically towards the end of the summer, 

 and owe their existence cliiefly to the melting of 

 the snow in the spring, the life-time of this form 

 is limited to only a few months of the year. In 

 the course of a comparatively short time, however, 

 it has passed through its developmental course, and 

 propagation then jiroceeds rapidly. As ali-eady stated, 

 the eggs in the ovisac always become surrounded In- 

 a very thick shell, and are evidently calculated to 

 stand the winter, and in the ensuing summer to 

 develop into a new generation. The sjieiues is thus 

 represented every year <inly by a single generation. 

 The eggs are deposited in the mud at the bottom 

 of the pond, and as this deposition of eggs is re- 

 ])eated several times l)y each female, a considerable 

 number of eggs is soon amassed, wliich ensui'es the 

 existence of the species in those places that are favor- 

 able to its well-being. It is not until Midsummer 



