26 



Tubularia variabilis, n, sp. 



(Tab. I, Flg-. 4). 

 Foreløbig Beskrirelse. Bonnevie (29). 



Trophosome. Hydrocaulii.s ugrenet, sammeiisat nederst, 

 stiger op fra en sterkt iorgrenet Hydrorhiza. Tydelig 

 Længdestribning; ingen Krave. Hydrantlien liar 25 — 35 

 proximale Tentakler, ca. 2 era. lange, og distale Tentakler 

 i flere tætstillede Kredse ; de er 2— 3 mm. lange. 10 — 20 

 Blastostyler, ca. 2 cm. lange, sidder i en Kreds lige over 

 de proximale Tentakler. 



Gonosome. Fra Blastostylerne udvikles fastsiddende 

 medusoide (iunoforer. forsynede med et varierende Antal 

 Radialkanaler og med Riljlier udvendig, der i Antal og 

 Anordning svarer til Eadialkanalerne . 



Exemplarer af denne Art blev under Nordh.-Exp 

 fanden jiaa to Stationer, begge Steder kun enkeltvis. Det 

 ene af disse var afskaaret et Stykke nedenfor Hydrantlien 

 men paa det andet ser man den meget sterkt forgrenede 

 Hydrorliiza og en Samling af Stammer, som stiger op fra 

 denne. Kun en af disse bærer Hydranth. Denne er meget 

 stor og af en betydelig grovere Bygning end den samme 

 hos T. indivisa. Dens Høide — fra Basis til Toppen af 

 de distale Tentakler — er 12—1-1 mm., og Diameteren 

 over de udspændte proximale Tentakler er ca. 50 mm. 



Blastostylerne er ugrenede, ca. 2 cm. lange, med de 

 største Gonoforer siddende distalt, og ved Basis af disse 

 sees ofte 2 — 3 ganske smaa Knopper. Gonoforernes Byg- 

 ning er Artens mest karakteristiske Kjendetegn, og deres 

 eiendommelige Udseende vil strax være paafaldende. De 

 er udvendig besat med en Del smale, jioie Kamme eller 

 Ribber, som strækker sig i Gonoforernes Længderetning 

 og som tiltager i Hoide mod deres distale Ende. De 

 rækker et Stykke fremover denne og sæiiker sig derpaa 

 brat ned mod dens Midtpunkt. 



Ved Undersøgelse paa Snitserier viser tlet sig. at der 

 indenfor hver Bibbe betinder sig en Badialkanal, og at 

 Ribberne er dannet ved en Ektodermfortykkelse udenfor 

 hver af disse Kanaler. 



Medens Radialkanalernes Antal hos de øvrige Tubu- 

 larider er konstant, er det lios denne Art meget variabelt. 

 Paa samme Blastostyl liar jeg saaledes fundet Gonoforer 

 med 3 Radialkanaler. med 5 og med 6, og med et tilsva- 

 rende Antal Ribber udvendig; af disse var den Gonofor, 

 der havde 5, videre udviklet end de ovrige, og det ser saa- 

 ledes ikke ud, som om Radialkanalernes Antal stiger med 

 Gonoforernes Alder. 



T liver Gonofor udvikles en Actinula. 



Pindested. St. 325, St. 3G2. 



Til denne Art maa sandsynligvis lienfores en Tiihn- 

 laria, der ogsaa blev funden under Nordli. -Exp.; men den 

 er saa lidet udviklet at Bestemmelsen af den Idiver usikker. 



Den er afskaaren et Stykke nedenfor Hydranthen, 

 og om dens Hydrorhiza og Stilkens nedre Forløb vides 



Tubularia variabilis. n. sp. 



(Pl. L fig. 4). 

 Prelimiuary descriptiou, Bonnevie (29). 



Trophosome. Hydrocaulus unramified, coniposite 

 lielow, rising from a thickly ramitied hydrorhiza. Distinct 

 longitudinal stripes, no collar. The hydranth has from 25 

 to 35 proximal tentacles, about 2 cm. in length, and distal 

 tentacles from 2 to 3 mm. in length in several circles 

 standing close together. From 10 to 12 blastostyles about 

 2 cm. long, stand in a ring just above the proximal ten- 

 tacles. 



Gonosome. Fixed medusoid gonophorcs are deve- 

 loped from the blastostyles, furnished with a varying 

 number of radial canals, and witli external ribs correspon- 

 ding ill number and arrangement with the radial canals. 



During the Norw. N. Atlan. Exp., specimens of this 

 species were found at two stations, one specinieii at each. 

 One of these was cut off a little below the hydranth, hut 

 in the other, the thickly ramitied hydrorhiza is visible, 

 and a number of stems arising from it. Only one of these 

 carries a hydranth. This is very lai-ge, and of mucli 

 coarser structure than in T. indii-isa. Its lieight, from 

 the base to the top of the distal tentacles, is between 12 

 and 14 mm., and the diameter across the extended proxi- 

 mal tentacles is about 50 ram. 



The blastostyles are unramified, about 2 cm. in length 

 with the largest gonophores situated distally, and at the 

 base of the latter there are often two or three quite small 

 buds. The structure of the gonophores is the most charac- 

 eristic feature of the species, and their peculiar appea- 

 rance will at once attract attention. They are marked 

 externally with .a few liigh, narrow ridges or ribs, exten- 

 ding in the longitudinal directioii of tlie gonophores, and 

 iiicreasing in height towards their distal end. They extend 

 a little beyond this, and then drop suddenly towards its 

 central point. 



On examination of the sectional series, it appears 

 tliat witliin each rib there is a radial canal, and that the 

 rilis are formed by a thickening of the ectoderm outside 

 these canals. 



Whereas the nnmber of radial canals in the other 

 Tulndarklce is constant, in this species it is very variable. 

 I have, for instance, found on one blastostyle gonophores 

 with 3, 5 and 6 radial canals, and a corresponding number 

 of external ribs. The gonophore that bad 5 radial canals 

 was more developed than the otliers, so it does not appear 

 that the number of radial canals increases with tlie age 

 of the ^'onophore. 



In each gonojihore an actinula is developed. 



Locality. Station 325, Station 362. 



It is probalily to this species that a Tuhularia. also 

 found (luring the N. Atlan. Exp., but so little developed 

 that its identification is uncertain. must be referred. 



It has been cut off a little below the hydranth, and 

 thus nothing is knowii of its hydrorhiza and the lower 



