48 



Gonosome. Fastsidilonde Goiioforer, 1 — 2 miii. lange, 

 med 4 Radialkanaler, der udcnpaa viser sig som mørke- 

 brune Liiiier; disse løber sammen mod den distale Ende i 

 et firkantet Skjold, som i sin Midte bærer en hvid Teg- 

 ning, som af et Firkløverblad. Gonoforerne sidder kun 

 en paa hver Blastostjl, og disse, hvis Størrelse er forsvin- 

 dende ligeoverfor Gonoforerncs, er sterkt bøiede, saa at 

 Gonoforerne faar en opret Stilling. 



Hydranthcrnes Størrelse og Gonoforernes eiendomme- 

 lige Udseende — dens Tegninger kan saavidt sees med 

 blotte Øine — gjør denne Art let kjendelig. Da Blasto- 

 stylerne er saa smaa og samtidig bøiede, saa at Gonofo- 

 rernes Stilling blir ojiret, ser det ved en overfladisk Under- 

 søgelse ai Kolonien ud. som om Gonoforerne udgaar fra selve 

 Hydrorhiza. Alle Individer i en Koloni er af samme 

 Kjøn, Jeg har kun liavt Anledning til at undersøge en 

 Koloni af Hunkjon, og her kan man allerede udvendig og 

 med svag Forstørrelse se Æggene gjennem Gonoforvæggen, 

 som en regelmæssig Mosaik af 6-sidede Polygoner. 



Pindested. St. 270. 



Hydractinia minuta, n. sp. 



(.Tab. I, Fig-. :i). 

 Forelobig Beskrivelse, Bonnevie (ill). 



Trophosome. Hydrantlier 1 — 2 mm. hoie, med ca. 

 12 Tentakler, der' er 2 — 3 mm. lange. Blastostyler næsteii 

 usynlige og uden Spor af Tentakler. 



Gonosome. Fastsiddende Gonoforer uden Radial- 

 kanaler, sidder å— r) i en Kreds ora den forsvindende Bla- 

 stostyl. Ca. G Æg udvikles i hver Gonofor. 



Denne lille Art, der nærmest ligner H. JmiiiiJ/s 

 Bonnevie, og som sammen med denne representerer Slægtens 

 mindste Arter, udmerker sig ved den fuldstændigo Atrofi 

 af de gonoforl)ærende Hydrantlier. 



Pindested. (Spitsbergen) St. 374, 



Fani. Eudendridae. 



Hydrantlier nted køUefomief Prohosci^. sterkt ndridede 

 i den iwoximcde Del, der hærer en Kreds tj-aadjuiiulge 

 Tentakler. 



Paa Grund af Hydranthens Form saavel som Gono- 

 forernes eiendommelige Udvikling har SeJnwider atter stillet 

 Slægten EiideiidriuDt i en egen Familie, efterat Levinsen 

 havde sat den ind under Fara. Bougainrillidae, og jeg er 

 enig med ham i, at Slægten bor indtage en Særstilling i 

 Systemet. 



Gonoforerne er ikke Medusoide; de har en meget 

 enkel Bygning og kunde passende Iteholde den af Alliiinn 

 indforte Betegnelse „simple Sporosacs". 



Gonosome. Fixed gonophores. I —2 mm. long, with 

 4 radial cauals, that appear, from the outside, as dark 

 brown lines running together towards the distal end, and 

 forming a square schield, in the middle of which tliere is 

 a white tigure like a quatréfoil. There is only øne gono- 

 pliore on each blastostyle, and the blastostyles, whose size 

 is infinitesimal as compared with that of the gonophores, 

 are very much bent, thus giving the gonophores an erect 

 position. 



The size of the hydranths, and the characteristic 

 appearance of the gonophores (the markings on theni are 

 barely visible to tiie naked eye) cause this species to be 

 easily recognisable. From the fiict of the blastostyles being 

 so small, and at the same time so bent that the position 

 of the gonophores becomes erect, it appears, on a super- 

 ficial examination, as if tlie gonophores arose from the 

 hydrorhiza itself. All the persons in a colony are of the 

 same sex. The only colony I have had the opportunity 

 of examining was one of females; and frora without, when 

 slightly magnified, the eggs raight be seen through the 

 wall of the gonophore, like a regular mosaic of hexagons. 



Locality. Station 270. 



Hydractinia minuta, n. sp. 



I Pl. I, tig. 3). 

 Prcliminary deseription, Bonnevie ('29). 



Trophosome. Hydranths I — 2 unn. high, with aliout 

 12 tontacles, 2 or 3 mm. in length. Blastostyles almost 

 invisible, and without tentacles. 



Gonosome. Fixed gonophores without radial canals, 

 from 3 to 5 in circle round the inconspicuous blastostyles. 

 About G eggs develope in each gonophore. 



This little species, which principally resembles H. 

 humilis Bonnevie, and, witli it, represcnts the smallest 

 species of the genus, is distinguished l)y tiie cømplete 

 atrophy of tlie gonophorebearing hydranths. 



Locality. i^Spitzbergen) Station 374. 



Fani. Eudendridae. 



H[/dritnths wifli clarate protjoseis, (jreMJy e.rpanded in 

 tite proximid part. ivhich liears a circle of fil if orm tentacles. 



On account of the form of the hydranth. .and the 

 peculiar development of the gonophores, Schneiiler has 

 again placed the genus Eiidendrium in a family of its own. 

 after Levinsen had placed it in the family Boungainvillidae. 

 I agree with him in considering that the genus occupies a 

 peculiar position in the system. 



The gonophores are not niedasoid. They are of a 

 very simple structure, and raight very well retain the de- 

 siguation introduced by Alhnann of „siraple sporosacs" 



