59 



Polyartemia forcipata, Fischer. 



(PI. IX & X). 



Poli/arteniia forcipata, Fischer, Midden dorff'.s Sibiriscbe Reise, 

 Bd. 'J. Zoologie, p. 154, Tab. VII, Fig. 24—28. 



Artscharacter. — Legemet smalt lylindriskt, 

 iiæsten jevnt tykt hos Hunnen, noget afsmalnende 

 bagtil hos Hannen. Hovedet hos Hunnen forholds- 

 vis lidet og afrundet fortil, hos Hannen betydelig 

 bredere og endende med 2 stumpt coniske, nedad- 

 krummede Frontalfortsatser. Halen og Kjonsringene 

 tilsammen neppe mere end halvt saa lang som den 

 fodbærende Del af Kroppen. Hunnens Ægbeholder 

 In-edt afrundet fortil med et knudeformigt Frem 

 spring til hver Side. Hannens ydre Kjonsvedhæng 

 simpelt cylindriske og omtrent af Halens halve 

 Længde. Øinene kolleformige, omtrent af Længde 

 som Hovedets halve Tværdiameter. Første Par Fø- 

 lere forholdsvis smaa, kortere end Øinene. Andet 

 Par Følere hos Hunnen betydelig kortere end Ho- 

 vedet, endende i en triangulær Flig; samme Folere 

 hos Hannen særdeles store, tregrenede, de 2 forreste 

 (irene tangformigt knimmede i Enden og fint cili- 

 erede i den indre Kant, den bagerste Clren kort, 

 lige nedad rettet og tæt haaret i Enden. Hale- 

 pladerne bredt laneetformige, omtrent dobbelt saa 

 lange som de er brede ved Basis. Legemet gjennem- 

 sigtigt med svagt gronligt, blaaligt eller rødligt 

 Skjær. Hannen sædvanlig lys gulagtig. Hunnens 

 Kjonsringe oventil med 2 ultramarinblaa kantede 

 Pletter, mellem hvilke er 2 smale Striber af samme 

 Farve, Ægbeholderen orangefarvet nedentil. Hun- 

 nens Længde indtil Ki mm, Hannens 10 mm. 



Bemærkninger. — Denne eiendommelige Phyllo- 

 pode blev først opdaget under Middendorffs Reise i 

 Sibirien og er kortelig beskrevet under ovenstaaende 

 Navn af S. Fischer, sammen med andre under Rei- 

 sen indsamiede Entomostraceer. Den er senere 

 ogsaa gjenfunden af andre Forskere, uden at dog 

 endnu nogen mere udforlig Beskrivelse er leveret. 



Beskrivelse af Hunnen. 



Længden af Legemet, fra Panderanden til Enden 

 af Halebladene, naar op til 16 mm. Dog finder man 

 den, saaledes som Tilfældet er med andre Phyllo- 

 poder, slægtsmoden længe for den har naaet denne 

 Størrelse. 



Legemet er (se Tab. IX, Fig. 1 og 2) slankt, 

 cylindriskt, og næsten af ens Bredde, dog hos fuldt 

 udviklede Li divider kjendeligt opsvulmet bagtil i 

 Kjonsregionen. Man kan adskille de samme Krops- 



Polyaptemia fopcipata, Fischer. 



(Pl. IX &. X). 



Polyartemia forcipata, Fischer, Middendorffs Siberische Reise, 

 Bd. 2. Zoologie, p. 164, Tab. III, fig. 24—28. 



Specific characters. — Body narrow cylindrical, 

 of almost uniform thickness in the female, tapering 

 in the male. Head in female eomjiaratively small 

 and roiinded in front, in male considerably broader, 

 and ending in two Tjluntly conical, decurved fron- 

 tal processes. Tail and genital segments together 

 scarcely more than half as long as the pedigerous 

 part of the body. Marsupium of female broadly 

 rounded in front with a nodiform protuberance on 

 each side. External sexual appendages of male 

 simple cylindrical, and about half the length of the 

 tail. Eyes clul)-shaped, about the length of half 

 the transverse diameter of the head. First pair of 

 antennæ comparatively small, shorter than the eyes. 

 Second pair of antennæ in female considerably 

 shorter than the head, and ending in a triangular 

 lappet; in male very large, tripartite, the two fore- 

 most rami being curved like a forceps at the end, 

 and finely ciliated on the inner margin, the hind- 

 most ramus short, pointing straight inwards, and 

 densely hairy at the extremity. Caudal lamellæ 

 broadly lanceolate, about twice as long as they are 

 broad at the base. Body transparent, with a faint 

 green, blue or red tinge: that of male generally 

 pale yellow. Genital segments of female above with 

 2 angular ultramarine-blue patches, between which 

 there are two narrow stripes of the same colour. 

 Marsupium orange-coloured below. Length of female 

 up to Hi mm, that of male, 10 mm. 



Remarks. — This peculiar Phyllopod was fii-st 

 discovered during Middendorffs journey in Siberia, 

 and is briefly described under the above name by 

 S. Fischer, together with other Entomo.straca col- 

 lected during that journey. It was subseijuently 

 also found by other naturalists, notwithstanding 

 which, no more detailed description has as yet been 

 furnished. 



Description of the Female. 



The lengtli of the body, from the frontal mar- 

 sin to the end of the caudal lamellæ, attains to 16 

 mm. It is found, however, as is also the case with 

 other Phyllopoda, sexually mature long before it has 

 attained this size. 



The body (see PL IX, figs. 1 and 2) is slender, 

 cylindrical, and of almost uniform breadth through- 

 out, though, in fully developed animals, perceptibly 

 distended posteriorly in the sexual region. The 



