der indtager Rygfladen. Paxillerne, som’ bære den ydre 
Ryghud, ere ved dels udelte, dels flerdelte Basaler fæstede 
til Kalkskelettet. Bugfladens Interbrachialrum udfyldte af 
en gjennemsigtig Membran, støttet af lange Kalknaale. 
Paa hver Side af Armene en Rekke semilunære Vetral- 
aabninger forsynede med Klapper. Ingen Hudgjeller. 
Artskarakter. 
Hymenaster pellucidus, W. Thomson. Skivens Ryg- 
side hvælver sig imod Centrum. Bugsiden flad. Forhol- 
det imellem den lille og store Radius som 1:2. Huden 
5 store Paxiller om Traktaabningen, hver 
bærende 6—8 korte og 8—10 lange Kalknaale; de øvrige 
Paxiller have 4 lange og 3 korte Naale. Hver Adambu- 
lacralplade har 3 Pigge, 2 mdad mod Bugfuren, 1 udad 
mod de semilunære Ventralaabninger. Madreporpladen 
rund. Farven rosenrød, spillende i det Violette. © 
gjennemsigtig. 
Vi have foretaget endel Maalinger, hvoraf det frem- 
gaar, at Forholdet imellem den lille og store Radius er 
lidt forskjellig efter Søstjernens Størrelse. 
Forholdet imellem den lille og store Radius: 
1 Exemplar af 12”" Diameter 1 : 12). 
1 — > 162 — IL 3 Tf 
ra He PS 
Lis eye MEG 
n += Mr 5, he 1), 
1 — ry Aopen — 1 3 Ga 
Saue OF heme) 
vet Ferie SOGN 
Findested. 
Station 35, et Par Exemplarer. 
12—15 Expl. 124, 
et Par smaa Expl. 
303, et Expl. 
40, 2 Exempl. 53, 
nogle Expl. 205, et stort Expl. 223, 
224, et stort Expl. 295, et Par Expl. 
353, 3 Expl. 363, det storste Expl. 
Udbredning. 
Slægten synes at have en overordentlig vid Udbred- 
ning ifølge de forelobige Meddelelser om Challenger-Expe- 
ditionen. 
80 
of the large body cavity or chamber which occupies the 
dorsal surface. The paxillæ which expand the exterior 
dorsal integument, are secured to the calcareous skeleton, 
by their, partly compact, and partly, divided basal parts. 
The interbrachial space of the actinal surface is covered 
by a translucent membrane, supported by long calcareous 
needles. On each lateral margin of the rays, there is a 
series of semilunar apertures, furnished with flaps. There 
are no integumental gills. 
Specific character. 
Hymenaster pellucidus, W. Thomson. The abactinal 
disk arches towards the centre. The actinal surface is 
flat. The proportion between the disk radius and the brach- 
ial is, as 1:2. The integument is translucent. 
There are five large paxillæ round the funnel-shaped ap- 
erture, each carrying 6—8 short, and 8—10 long, calear- 
eous needles, the remaining paxillæ have 4 long, and 3. 
short needles. Each adambulacral plate has 3 spines, 2 of 
them facing inwards, towards the ventral furrow, and the other 
one facing towards the semilunar ventral apertures. The 
madreporite is circular. The colour is rosy red, tending 
to violet. 
We have instituted a number of measurements, from 
which, it appears that the proportion between the disk 
radius and the brachial radius is a little different, accord- 
ing to the size of the starfish. 
radius 
Proportion between the disk-radius and the brachial 
radius. 
1 specimen of 12”” diameter 1 : 17». 
I Glo, KG == IL 3 We 
do SSR Ig 11805 
Ll, am — Hg TF 
Lem » 36mm - — Il 3 es. 
1 do . Ag — Tey 
QC. gone | e522 
1 do  ,, COV =. ely, 
Habitat. 
Station No. 35. <A couple of specimens. 
— » 40. Two specimens. 
— » 53. 12—15 specimens. 
—  , 124. A few specimens. 
— p 205. A large specimen. 
— , 223. A couple of small specimens. 
— p 224. Å large specimen. 
= s 295. A couple of specimens. 
— » 303. One specimen. 
— , 353. Three specimens. 
— ~,, 363. The largest specimen. 
Distribution. 
This genus appears to have an extremely wide range 
of distribution, judging by the preliminary report of the 
Challenger-Expedition. 
