47 



Perigonimus abyssi, G. (). 8ais. 



Trophosome. Hydrorliiza icticulær. krybcnde: Hy- 

 drocaulus oprct, ugrenet, 1 — 2 iiiin. hoi. dækket af pn blod 

 rynket Perisarc, der omsluttpr Hydrantlicns nedorste Del. 

 Disse har ri — S Tentakler. 



Gonosome. Gonopliorer udgaar Ira Hydrocaulus eller 

 Hydrorlii/.a. udvikler sig sandsynligvis til fri Meduser. 



Findested. Fondet paa Xuciila fiminltda ved Sta- 



tion 



Gen. Hydractinia 



kommer efter sin Diagnose til at omfatte de tidligere Fami- 

 lier Hf/(hactini(hie og Podocarynidae, der kun adskilte sig 

 ved Gonoforernes Udviklingsgrad. 



Hydractinia allmanii. n. sp. 



(Tab. I, Fig. 1). 

 Foreløbig Beskrivelse, Bouuevie (2!i). 



Trophosome. Hydranther li — 7 nini. iioie. med 

 mange Tentakler (Antallet varierer) i flere tætstillede 

 Kredse. Blastostyler smaa fea. '/j mm.) med rudimentære 

 Tentakler. 



GonoBome. Fastsiddende Gonoforer med 4 lladial- 

 kanaler, som Regel to ligeoverfor liinanden paa hver Bla- 

 stostyl, og disse to paa meget forskjelligt Udviklingstriu. 



Som jeg nævnte i min foreloliige Meddelelse danner 

 denne Art, sammen med den nedenfor beskrevne H. ornaia 

 et Mellomled mellem de tidligere kjendte Arter af Jli/drac- 

 tinia og Podocori/iie, idet deres Gonoforer er udstyret med 

 Radialkanaler uden at de dog nogensinde udvikler sig til 

 fri Meduser. Det viser sig saaledes ogsaa her, at der 

 intet sprang er mellem de Arter, der har de simpleste 

 fastsiddende Gonoforer og saadanne, iivis Gonoforer bliver 

 til fri Meduser, men at man inden Slægten Hijdradinia, 

 ligesom indenfor saamange andre Hydroideslægter, har en 

 hel sammeniiængende Kjæde af Arter, hvis Gonoforer naar 

 de forskjellige Udviklingstriu mellem de nævnte Yder- 

 punkter. 



Findested. St. 137, 312. 



Hydractinia ornata, n. sp. 



(Tab. I, Fig. 21. 

 Foreløbig Beskrivelse, Bonnevie ('29). 



Trophosome. Hydranther ca. 10 mm. lange, med 

 ca. 12 Tentakler. Blastostyler meget smaa og med rudi- 

 mentære Tentakler. 



Perigonimus abyssi, G. 0. Sårs. 



Trophosome. Hydrorliiza reticulate. creeping; hydro- 

 caulus ercct, unramitied, from 1 to 2 mm. high, covered 

 by a soft. wrinkled perisarc, whieli surrouiuls tlie lower 

 part of tiie hydranths. These have from 5 to 8 teutacles. 



Gonosome. The gonopliores rise from the hydi'0- 

 caulus lU' liydrorliiza, and probably develope into free 

 medusæ. 



Locality. Fouiul npon Xiicuhi tiiin/dida, at Sta- 

 tion 32J. 



Gen. Hydractinia. 



This genus, according to its definition, will embrace 

 the earlier families, Hydraciinidæ and Podorort/n/dæ. wliich 

 difiered only in the degree of development to which the 

 gonophores attained. 



Hydractinia allmanii. u. sp. 



(Pl. I. fig. 1). 



Prcliminary dcscription, Bonnevie (2'J). 



Trophosome. Hydranths 6 or 7 mm. high. with 

 numerous tentacles (number variable) in several circles set 

 close together. Blastostyles small (about '/^ mm.) with 

 rudimentary tentacles. 



Gonosome. Fixed gonophores witli 4 radial canals. 

 two. as a rule, upon each blastostyle, opposite one another, 

 and at very different stages of development. 



As I^mentioned in my ]ireliniinary communication, 

 this species. witli H. ornata, described below, forms an 

 intermediary link l)etween tiie prcviously known species of 

 Hiidractinia and Podocoryne. their gonophores being fur- 

 nished with radial canals, and yet never doveloping into 

 free medusæ. It ajjpears here too, tiiat there is no gap 

 between tlu' species with the simplest fixed gonophores, 

 and those whose gonophores turn into free medusæ; in 

 the genus Hydradiniu. as in so many other hydroid genera, 

 there is a connected chain of species, whose gonophores 

 attain the various stages of development between the above 

 extremes. 



Locality. Stations 137, 312. 



Hydractinia ornata, n. sp. 



Pl. 1. tig. 2,. 

 Preliminary descriptiou, Bonnevie (29). 



Trophosome. Hydranths about lU mm. long, witli 

 about 12 teutacles. Blastostjdes very small, and wuth rudi- 

 mentarv tentacles. 



