37 



i Stammen eller Grenene have været faa, spredte Spikier, 

 hvorfor saadanne Kolonier vanskelig skulle kunne hen- 

 føres til nogen af de to Slægter, men maatte staa midt 

 imellem. For at lette Oversigten har jeg derfor troet at 

 burde dele Slægten Duva i to Linier, — den ene om- 

 fattende de Arter, hos hvem den største Del af Zoantho- 

 demets Stamme og samtlige Grene med Forgreninger ere 

 uden Spikier, — og den anden, omfattende de Arter, hvor 

 hele Zoanthodemet er forsynet med saadanne. 



Slægtskarakteren for Duva vil som Følge heraf blive 

 stillet saaledes : 



Zoanthodemet trædannet, forgrenet. Grenene nøgne 

 i større eller mindre Udstrækning fra Stammen, delende 

 sig i mindre Grene, der hver bære paa deres Ende flere 

 Polyper, som dels ere sammenvoxede ved Granden, dels 

 skilte ved et smalt Coenenchym. Polyperne ikke retrak- 

 tile, vel udviklede og rigt forsynede med Spikier, især paa 

 hele Bygsiden. Enten er hele Zoanthodemet rigt paa 

 Spikier, eller Størstedelen af Stammen, samt Grenene og 

 Smaagrenene ere uden saadanne. Septa uden Kalk. 



Underaf deling. 



A. Hele Zoanthodemet spikelholdigt. 

 Hertil hører : 



Duva arborescens, n. sp. 

 — - aurantiaca, n. sp. 



— frigida, n. sp. 



— glaeialis, n. sp. 



B. Størstedelen af Stammen, Grenene og deres Forgre- 

 ninger uden Spikier. 



Hertil hører: 



Duva spitsbergensis, n. sp. 



— violacea, n. sp. 



— fiava, n. sp. 



— cinerea, n. sp. 



Duva arborescens, n. sp. 



Tab. II, Fig. 42—54, Tab. III, Fig. 1 — 17. 



Zoanthodemet indtil 120""" høit. Stammen er rund, 

 glat, furet efter Længden med en lidet udvidet Basaldel, 

 der er 60""" i Omkreds, og en temmelig rig Forgrening, 

 lige fra 20""" fra Grunden og op til Toppen, Tab. III, 

 Fis. 1. 



must be added, that in a few species I have found in- 

 dications of a transition, inasmuch, for instance, that 

 either in the stem or the branches, there have been few 

 dispersed spicules, and therefore such colonies could with 

 difficulty be assigned to either of the two genera, but 

 must be placed intermediately between them. In order, 

 therefore, to make the review easier, I have thought 

 it desirable to treat the genus Duva under two subdivi- 

 sions, the one subdivision including the species in which the 

 larger part of the stem of the Zoanthodem and all the 

 branches with their ramifications are devoid of spicules; 

 and the other subdivision including the species where the 

 entire Zoanthodem is furnished with them. 



The generic character of Duva will, in consequence 

 of this, be stated, thus: 



The . Zoanthodem arborescent, ramous. The branches 

 bare for a greater or lesser extent from the stem, rami- 

 fying into branchlets, each of which carries, on its extre- 

 mity, several polyps, which, partly, are concreted together 

 at the root, partly, are separated by a narrow sarcosoma. 

 The polyps non-retractile, well developed, and richly sup- 

 plied with spicules, especially on the entire dorsal side. 

 The entire Zoanthodem is, either, rich in spicules, or 

 the greatest part of the stem and, also, the branches and 

 branchlets are devoid of these. — Septa non-calcareous. 



Subdivisions. 



A. The entire Zoanthodem containing spicules. 

 To this subdivision pertain: 



Duva arborescens, n. sp. 



— aurantiaca. n. sp. 



— frigida, n. sp. 



— glacialis, n. sp. 



B. The greater part of the stem, the branches and 

 their ramifications, devoid of spicules. 



To this subdivision pertain. 



Duva spitzbergensis, n. sp. 



— violacea, n. sp., 



— flava, n. sp. 



— cinerea, n, sp. 



Duva arborescens, n. sp. 



PL II, figs. 42-54. PI. Ill, figs. 1- -17. 



The Zoanthodem measures, up to 120""" in height. 

 The stem is cylindrical, smooth, and longitudinally grooved, 

 and it has a slightly expanded basal part, measuring 60""" 

 in circumference, and a rather rich ramification extending 

 through the entire length, from 20'"'" above the root up 

 to the summit (PI. Ill, fig. 1). 



