99 
indre Flade har to stærke Sidefordybninger, der adskilles 
ved et næsten fladt Midtparti, Fig. 12. 
Ed. Perrier har i sin summariske Beskrivelse 
nye Asterider opført to nye Arter af Slægten Korethraster, 
nemlig: Kor. palmatus og radians. Hos begge disse Arter 
har han iagttaget Tentakelporer imellem Ryghudens Kalk- 
plader, der skulle være firkantede med imdskaarne Rande, 
hvorved Aabningerne for Tentakelrørene fremkomme. Dette 
er ganske forskjelligt fra, hvad der finder Sted hos Koreth. 
hispidus; thi her findes ingen Tentakelporer, og saadanne 
kunne heller ikke forekomme, da Kalkpladerne, hvoraf Ryg- 
hudens Skelet bestaar, ikke have noget Indsnit men ere 
taglagte saaledes, at ingen Aabning findes imellem dem, 
Fig. 3. 14. 
over 
Af den ovenfor leverede Beskrivelse fremgaar det, at 
Korethraster vanskeligen kan henføres til nogen af de for 
Asteriderne grundede Familier. Nærmest maatte den vel 
henføres til Familien Asterimidæ; men den adskiller sig fra 
denne ved fuldstændig Mangel paa Interbrachialrum, ved 
det særegne Hudskelet, som danner et sammenhængende 
Kalkpantser, bærende ganske eiendommelige Paxiller. Fra 
Familien Pterasteridæ, hvortil Ed. Perrier er tilbøielig til 
at henfore den, adskiller den sig end mere. Den har jo 
intet Hulrum paa Rygfladen, den har ingen Kalkstøtter, 
der bære Ryghuden som hos Pteraster, og endelig er Hud- 
skelettet saa ganske forskjelligt fra denne, at der forment- 
lig ikke kan være Tale om at indlemme den 1 Familien 
Pterasteride. Under disse Omstændigheder synes det rime- 
ligst at danne en ny Familie for den, som da kunde kal- 
des Korethrasteridæ. 
Slægtskarakter. 
Leget hvælvet, 5-armet. Armene korte, meget smale 
ved Grunden. Rygtfladen dækket af artikulerende Paxiller 
forsynede med lange Naale. Analaabningen subcentral. 
Madreporpladen tæt ved Anus. Ryggens Hudskelet bestaar 
af flade, taglagte Kalkplader, der danne et sammenhæn- 
gende Pantser. Bugens Hudskelet bestaar af paatvers 
gaaende Kalkribber, der indtage Rummet imellem Ambu- 
lacralfuren og Armens Rand. 2 Rækker Fodder med Su- 
geskive uden Spikler. Ingen Pedicellarier. 
Artskarakter. 
Legemet tykt. Forholdet imellem den lille og store 
Radius som 1:4. Paxillerne paa Rygfladen bestaa af 6— 
10 lange Naale, der ved deres brede Grunddel ere for- 
enede ved stærkt Bindevæv og danne en konkav Ledflade. 
Ambulacralfuren forsynet med to Rækker flade, hule Pigge. 
Paa Midten af Rummet imellem Ambulacralfuren og Ar- 
mens Rand en Rekke lange, ligeledes fladtrykte, hule 
side of this ridge, there is a slight cavity (fig. 11). The 
inner surface has two deep lateral cavities, separated 
from each other by a nearly flat mesial belt (tig. 19). 
Ed. Perrier in his summary description of new Ast- 
eridæ, has ranked, two new species of the genus Koret- 
hraster, namely, Korethraster palmatus and radians. In both 
of these species, he has observed tentacular pores between 
the calcareous plates of the abactinal integument, and which 
are stated to be square, with concave margins, producing 
the openings for the tentacular pores. That is perfectly 
different from what is found in the case of Korethraster 
hispidus, because, in it, no tentacular pores are found, and 
neither could they be found, because, the calcareous plates 
of which the dorsal dermal skeleton consists, have no 
incision, but are imbricate, in such a manner that no 
opening is left between them (figs. 3. 4). 
From the above description, it is evident, that Koret- 
hraster can not easily be assigned to any of the established 
families of Asteride. The family of Astermidæ, is the 
one to which it approaches nearest, but it differs from it, 
in the complete absence of interbrachial spaces, and also, 
in the characteristic dermal skeleton forming a continuous 
calcareous armour plating, and carrying quite peculiar pax- 
ille. It differs from the family of Pterasteridæ to which 
Ed. Perrier is disposed to assign it still more. It has, 
for instance, no cavity on the dorsal surface. There are 
no calcareous supports expanding the dorsal integument 
as in Pteraster, and finally, the dermal skeleton is so com- 
pletely different from that, that there can, presumably, be 
no question of including it in the family of the Pteraster- 
ido. In these circumstances, it appears most reasonable 
to form a new family for it, which might be designated 
Korethrasteridæ. 
Generic character. 
The body arched; 5-rayed. 
narrow at the origin. 
The rays short, and very 
The abactinal surface covered by 
articulating paxillæ furnished with long needles. The anal 
aperture subcentral. The madreporite close to the anus. 
The abactinal dermal skeleton consists, of flat, imbricate 
calcareous plates, forming a continuous armour plating. 
The actinal dermal skeleton consists, of transverse calear- 
eous ribs, which occupy the space between the ambulacral 
furrow, and the margin of the ray. There are two series 
of suckers, free from spiculæ, and with sucker disks. No 
pedicellariæ. 
Specific Character. 
The body thick. The proportion between the disk radius 
and the brachial radius is, as 1:4. The paxillæ of the 
abactinal surface consist, of 6—10 long needles, which are 
united at their broad basal part, by strong connective tis- 
sue, and form a concave articulatory surface. The amb- 
wlacral furrow is furnished with two series of flat hollow 
In the middle of the space between the ambula- 
eral furrow and the margin of the rays, there is a series 
eye 
spines. 
