Pigge og paa Armens Rand en Rekke Pigge, hvis brede 
toto fo) I te) p) 
Ende er forsynet med 5 temmelig lange Spidser. 
Farven bleg gul; Fødderne mørkere gule. 
Findested. 
Station 124, et større og et ganske lidet Exemplar. 
Stat. 164, to mindre Exemplarer. 
Udbredning. 
Wyville Thomson fandt Korethraster hispidus syd for 
Færøerne i den kolde Area. Paa den k. k. østerrigs-un- 
garske Nordpol-Expedition blev den funden ved 79° 9’ N. 
18, 620 8” Ø, Ih. 
(ox 
Ilyaster mirabilis, n. g. 
Tab. VII, Fig. 15—19. 
et sp. 
Legemet femarmet, 30”” fra den ene Armspids til 
Den lille Radius forholder sig til den store 
Skivens Diameter 77”, Fig. 15. 
den anden. 
som 1: 29/4. 
Ryggen er flad, overalt besat med Paxiller, der ere 
dels runde, dels mere eller mindre aflange, temmelig fint- 
kornede og have efter deres Størrelse 3—6 Korn stund- 
om med et Midtkorn men hyppigst uden saadant, Fig. 16, 
17. Under Mikroskopet vise disse Korn sig som korte, 
knopformige, stærkt takkede Kalklegemer med en Ledflade 
paa Basaldelens Ende. 
Fra Skivens Centrum reiser sig paa Rygsiden en 8”” 
hoi, kegleformig Forlengelse, der er omtrent 2”” bred ved 
Grunden og smalner af efterhaanden, indtil den ved dens 
frie, noget afrundede Ende indtager en Tykkelse af om- 
trent 0.57", Fig. 15, 16. Denne eiendommelige Forlæn- 
gelse føles kompakt i sin største Længde, og kun dens 
brede Grunddel synes at være hul. Den overalt be- 
klædt med Paxiller, som staa langt fra hverandre, ere stil- 
lede i Tverrækker, der ligesom i Spiraler gaa fra Grunden 
‘op til Spidsen, som har et ganske lidet, nøgent Punkt. 
Disse Paxiller bære i Regelen 3, sjeldnere 4 temmelig 
lange Naale, Fig. 18. 
er 
Under Mikroskopet vise disse Naale sig egentlig at være 
lidt langstrakte Pigge med en liden Artikulationsflade paa 
den noget bredere Basaldel. 
Madreporpladen er aflang og sidder lige ved Randen 
af en Armvinkel. 
of long, also flattened and hollow spines, and on the 
margin of the rays, a series of spines, whose broad ex- 
tremities are furnished with five rather long points. 
The colour is pale yellow. The suckers a darker 
yellow. 
Habitat. 
Station No. 124. One large, and one quite small 
specimen. 
164. Two smallish specimens. 
Distribution. 
Wyville Thomson found Korethraster hispidus, south 
of the Faroe Islands, in the cold area. During the Imperial 
Austro-Hungarian North Polar Expedition it was found in 
TO? Y Wo I, CZ B’ 1, Ila 
Ilyaster mirabilis, n. 2. and sp. 
Pl. VII, figs. 15—19. 
The 
tween the 
body is 5-rayed, and the diameter, measured be- 
tips of two opposite rays, is 307". he disk 
radius bears to the brachial radius, the proportion of, 
1: 2°/,. The diameter of the disk is 7” (fig. 15). 
The abactinal surface is flat, and everywhere, beset 
with paxille, which are, partly, round, partly, more 
or less oblong, and rather fine-grained, and according to 
size, they are furnished with 3—6 grains, and also, occas- 
ionally, with a central grain, although, most frequently, they 
appear without that feature (figs. 16.17). Under the mic- 
roscope, these grains appear, as short knob-formed, strongly 
aculeated calcareous corpuscles, having an articulatory sur- 
face on the basal part. 
as 
In the centre of the abactinal disk, there rises a con- 
iform projection, 8”” high and about 2”” broad at the base, 
but gradually diminishing in thickness, until at its free 
somewhat rounded extremity, it becomes reduced to about 
0.5” thick (tig. 15.16). This peculiar appendix is, for the 
greater part of its length, compact to the touch, and only 
at the basal part, does it appear to be hollow. It is, ev- 
erywhere, clad with paxille placed wide apart from each 
other, in transverse series extending in spiral form, from 
the base to the extremity, and on the last named, there 
occurs, a quite small, bare spot. These paxillæ, usually, 
carry three, and more rarely, four rather long needles 
(fig. 18). 
Under the microscope, these needles appear to be, 
really, slightly elongate spines, with a small articulatory 
surface situated on the proportionately broader basal part. 
The madreporite is oblong, and is seated close to the 
margin of a brachial angle. 
