121) 



stillede Fortsatser, livoraf deu midtprste forestiller 

 Rostrum. 



Forekomst og Levevis. 



Det ene.ste Sted lier i Landet, livdr dmiie Pliyllo- 

 pode hidtil er observeret, er i Østfiii ni arken ved 

 Mat.^jok, en Biflod til Tana, hvor Prof. ("oUett fandt 

 den i Sommeren 188;'). Da jeg nogle Aar senere, i 

 1888, iDerei.ste Finmarken, nndlod jeg ikke at liesoge 

 denne Lokalitet, og var ogsaa saa heldig at tinde 

 den her i Slutningen af August meget almindeligt 

 i en grund, med talrige Vandplanter Iievoxet Grøft. 

 Alle Exemplarer var da fnldt udviklede og syntes 

 at have opnaaet sit Maximum af Størrelse. Skjondt 

 jeg noie undersøgte alle Danime og (Trotter i Om- 

 egnen, var det mig dog ikke niuligt at tinde noget 

 Spor af den andetsteds end netop i den omtalte 

 Groft, der saaledes maa have frembudt særlig gun- 

 .stige Forhold til dette Dyrs Trivsel. 1 Lobet af 

 nogle faa Dage indsamledes her et betydeligt Antal 

 Exemplarer, ligesom ( )bservationer anstilledes over 

 det levende T)yv i mine Excursion.sglasse. Dyrets 

 Bevægelser er temmelig klodsede og lidet ixdhol- 

 dende, bestaaende i et noget ixjevnt og ligesom riil- 

 lende Lob gjennem Yandet, hvorunder snart Ryg, 

 snart Bug vendes opad. Under Bevægelsen er Ho- 

 vedet helt fremstrakt af Skallen, saa at Aarerne fnldt 

 kan virke, og Valvlerne er herunder vidt aabne neden- 

 til. Jeg kunde ikke observere, at Dyret nogensinde, 

 som Tilfaddet er med Limnndia, fæstede sig til de i 

 Våndet værende Gjenstande. Naar Bevægelsen op- 

 liorte, sank D\-ret hurtigt til Bunden, og laa her 

 ofte i længere Tid nbevægeligt paa Siden, for saa 

 igjen at foretage en kort Udtlngt i Våndet. Hanner 

 og Hunner forekom næsten i samme Anta! og saaes 

 ofte i Copulation, hvorunder Hannen me<l sine Gribe- 

 fodder med stor Kraft omfatter Kanterne af Hun- 

 nens Val vier nedentil. Selve 1'arringsakten tik jeg 

 dog ikke observere. At dommc efterKiiidbakkcrnes 

 Bevælniiiig, s\-nes Dyrets Xa'iing at va-re mere 

 animalsk end Tilfældet er med de øvrige bivalve 

 I'hyllopoder, og bestaar rimeligvis for en .stor Del 

 af mindre Entoniostraceer. 



Udbredning. — Denne Phyllopode blev først 

 opdaget at O. F. Miiller i Damme nan- Kjøbenhavn, 

 og er ogsaa senere her gjenfunden. Foruden i Dan- 

 mark er den observeret ved Danzig af Liévin, ved 

 Dorjiat af (rrnbe. i liillerusland ved ('liarkow og i 

 ITngarn \t'd I 'est, endelig ogsaa i Sibirien. 1 sin 

 Udbredning synes den saaledes idethele, i Modsæt- 

 ning til Limnacliu, at være en østlig Form, og det 

 er aabenbart ad den Vei. nordenom den bøtniske 

 Bugt, at den har iidbredt sig til voi-t l.aiid. 



processes, the middle one of which rejireseiits the 

 rostrum. 



Oeeurreuce and Habits. 



The only place in this country (Norway) where 

 this Phyllopod has hitherto been observed is in East 

 Finmark, near the Matsjok, a tributary of the Tana, 

 where Prof Collett found it in the summer of 1885. 

 When some year.s later, in 1888, 1 travelled through 

 Finmark, I did not fail to visit this locality, and 

 had also the good fortune to find it there at the 

 end of August, very plentiful, in a shallow ditch 

 where numerous a([uatic plants grew. All the spe- 

 cimens were then fully developed, and seemed to 

 have attained their maximum size. Although I care- 

 fully examined all tlie ponds and ditches in the 

 neigliliourhood, I did not succeed in disc(jvering any 

 trace of it anywhere except in the said ditch, which 

 must thus have offered conditions especially favo- 

 rable to this animal's well-being. In the course of 

 a few days, a considerable number of specimens 

 were collected here, and observatiims made of the 

 living animal by watcdiing them in my collecting- 

 jars. The animal's movements are rather awkward, 

 and not very persevering, consisting in a some- 

 what uneven and, as it were, rolling course through 

 the water, sometimes witli the dorsal, sometimes 

 with the ventral side iqipermost. During the 

 movement the head is stretched right out of the 

 shell, so that the oars can have their full effect, 

 the valves meanwhile being wide o])en below. 

 T never observed the animal attaching itself to 

 objects in the water, as is the case with TJni- 

 nadin. ^\'lll■ll tin' motion ceased, it sank (juickly 

 to tiie liottom, and often lay there a long time on 

 its side, motionless, then again making a short ex- 

 cursion through the water. Males and females are 

 found ill almost e(|ual numbers; and are often seen 

 in copulation, during which the male, with its pre- 

 hensile legs, embraces with great jiower the lower 

 edges of the female's valves. The act of co])ulation 

 itself, however, I have not witnessed. .ludging 

 from the armature of the mandibles, the animal's 

 food apjiears to l)e more animal than is the case 

 with the other bi- valve Phyllopoda, and probably 

 consists to a great extent of smaller Entomostraca. 



Distribution. — This Phyllopod was first disco- 

 vered by ' '. F. Miiller, in ponds near Copenhagen, 

 and has also been found there again subsequently. 

 Besides in Denmark, it has been observed by Licvin 

 at Danzig, by Grube at Dorjiat, at Charkow in 

 Little Russia, at Pesth in Hungary, and lastl\- in 

 Silieria. It therefore a])])ears, in opposition to Lim- 

 nadin, to be, in its distribution, an eastern form, and 

 it is evidently by way of the north of the (tuU' of 

 Bothnia, that it has spread to onr land (Xorway). 



17 — G. 0. Sars: Fauna Xorveois;. 



