94 



Findested. 



Station 237. Nqgle meget smaa Exemplarer. 



Station 267. 2 Exemplarer. 

 Station 275. 4 Exemplarer. 



Artskarakter. 



Zoanthodemet indtil 35""" liøit. busket. Basaklelen 

 skiveformigt udvidet, fast, meget kalkholdig. Stammen 

 rund. den nederste Halvdel blottet for Grene, men tæt 

 besat med Foraminiferer. Grenene tykke, rigt besatte med 

 Polyper, ordnede saaledes, at hver Gren danner næsten en 

 Kugle. Stammen og Grenene spikelrige. Polyperne, der 

 udspringe direkte fra Grenene, ere 4 m? " lange, traktformige 

 med en kort Bagkrop. Tentaklerne 1.5""" lange, tykke og 

 noget afstumpede. Polypkroppen, især paa Bygsiden og 

 paa Tentaklerne, er meget rig paa Kalk; Pinnulerne uden 

 denne. Paa Basaklelen og nederst paa Stammen er 

 Dobbeltstjernen almindeligst. Paa Stammens øvrige Del 

 og Grenene er Dobbeltstjernen meget sjeldnere, men hei- 

 er enklere, næsten spindelformige Spilder hyppigst; paa 

 Polyperne ere Koller og Klubber almindeligst. 



Habitat. 



Farven. 



Stammen, Grenene, Polypkroppen og den nederste 

 Halvdel af Tentaklerne svag brunrød ; den øverste Halvdel 

 samt Pinnulerne mørk kastaniebrun. 



Embryologiske Undersøgelser. 



De ovenfor beskrevne Arter af Slægten Nephthya føder 

 levende Unger, hvilket forøvrigt er det Almindeligste blandt 

 Alcyoniderne. Hos alle fandtes forskjellige Utviklings- 

 stadier af de i Mave- og Svælghulheclen indesluttede Æg 

 og Embryoner; men da Exemplarerne vare opbevarede i 

 Spiritus, er det selvsagt, at Undersøgelserne maa blive 

 mangelfulde og ikke mindst derved, at det er ugjørligt at 

 fremstille en sammenhængende Række i Udviklingen. Paa 

 Nordhavsexpeditionen havde jeg hverken Tid, ei heller var 

 Søen saa rolig, at jeg kunde anstille embryologiske Under- 

 søgelser ; imidlertid tor de paa Spiritusexemplarer foretagne 

 Iagttagelser have nogen Interesse derved, at de udfylder 

 enkelte Huller i Alcyonidernes Embryogeni og for en Del 

 konstaterer de af Kowalevsky og Marion 1 anstillede Obser- 

 vationer over Alcyonidernes Udviklina;. 



1 A. Kowalevsky et A. F. Marion: Documents pour l'Mstoire 

 embryogénique des Alcyouaires. ilmiales du Musée d'histoire naturelle 

 de Marseille. — Zooloerie. Tome I. Memoire No. 4. Marseille 1883. 



Station No. 237. A few very small specimens. 

 Station No. 267. Two specimens. 

 Station No. 275. Four specimens. 



Specific characteristics. 



The Zoanthodem measures up to 35""" in height. 

 frutico.se; the basal part discoidally dilated, hard, very cal- 

 careous. The stem cylindrical, the lowest half part devoid 

 of branches but closely occupied by foraminifera. The 

 branches thick, richly beset with polyps, arranged so that 

 each branch forms, almost, a ball. The stem, and the 

 branches, rich in spicules. The polyps spring direct trom 

 the branches, measure 4""" in length, are infundibuliform, 

 with a short posterior body. The tentacles measure 1.5""" 

 in length, are thick and somewhat truncated. The polyp- 

 body, especially on the dorsal side and upon the tentacles, 

 is very rich in calcium. The pinnules noncalcareous. In 

 the basal part, and lowest part of the stem, the bistellate 

 spicular form is the most frequent. On the rest of the 

 stem, and the branches, the bistellate form is much rarer, 

 and, here, plainer, nearly fusiform, spicules are the most 

 frequent. On the polyps, subclavates, and ciavates, are the 

 most usual forms. 



Colour. 



The stem, the branches, the polyp-body, and the 

 inferior half-part of the tentacles are faint brownish-red. 

 The superior half-part, and the pinnules, dark chestnut-brown. 



Embryological Examination. 



Both the above described species of the genus Nephthya 

 give birth to living young, which is, also, the usual case 

 amongst the Alcyonoids. In both of them, different 

 developed stages in the ova and embryons contained in 

 the ventral cavity were found, but as the specimens were 

 preserved in alcohol, it is a matter of course that the 

 examinations must be imperfect, none the less so, that it 

 is impracticable to procure a continuous series in develop- 

 ment. On the North-Altantic Expedition, neither had I 

 time, nor was the ocean so calm that I could undertake 

 embryological examinations. However, the observations 

 made, upon the specimens preserved in alcohol, may have 

 some interest, because they serve to fill up some voids in 

 the embryogeny of the Alcyonoids, and to some extent they 

 confirm the observations made by Kowalevsky and Marion 1 

 upon the development of the Alcyonoids. 



1 A. Kowalevsky et A. P. Marion: Documents pour l'histoire 

 embryogénique des Alcyouaires. Annales du Musée d'histoire naturelle 

 de Marseille. — Zoologie. Tome I. Memoire No. 4. Marseille 1883. 



