tidligere beskrevne Paxillerækker og ere egentlig sammen- 
smeltede, saa at hele Ryghudens Skelet danner et fuld- 
stændigt Kalkpantser uden Tentakelporer, Fig. 3. Sam- 
mensmeltningen er næsten overalt saa komplet, at det har 
sine Vanskeligheder at skille Pladerne fra hverandre. 
Bugen er flad, og her fremtræder Armenes særegne 
Form meget tydeligt. Intet Interbrachialrum, Fig. 2. 
Ambulacralfuren er ikke meget bred, forsynet med 2 
Rækker cylindriske Fodder, som ere uden Spikler men 
have en vid Sugeskive.  Furens Rand har to Rader Pigge, 
hvoraf den ene er lidt indenfor og under den anden, Fig. 
8,a. Piggene i den inderste Rad ere de længste, forresten 
er Formen den samme. De have et noget fladtrykt Udseende 
men danne egentlig en hul Halveylinder, der er bredere i 
den næsten spatelformige, frie Ende, hvis Rand er krene- 
leret, Fig. 9, a imedens den smalere Del er rund, ikke 
hul, og har en Ledflade, Fig. 9,0, der artikulerer med en 
tilsvarende rund Knop paa Adambulaeralpladen. Disse 
Pigge ere efter Længden forsynede med mange Rækker 
fine, næsten runde. Huller og have et Hudovertræk. 
Udenfor Furepiggene findes omtrent paa Midten af 
Rummet imellem Ambulacralfuren og Armens Rand 
Reekke Pigge, fuldkommen lignende de 
en 
nys beskrevne, 
kun ere de noget længere, Fig. 8, e. Endelig findes paa 
Armens Rand en 4de Række Pigge, der ere forskjellige 
fra de øvrige, og som vi ville kalde Randpigge, Fig. 8, /. 
10. De ere smale ved deres Grunddel, der er rund og 
forsynet med en Ledflade, Fig. 10, a, og udvider sig blad- 
formigt mod den frie Ende, som har 5 temmelig lange Spid- 
ser, Fig. 10,:0, hvoraf de to, der danne Hjørnespidserne, 
ere de korteste. Den bladformige Del har noget indbøiede 
Rande, hvorved fremkommer en Hulhed, der er dybest ned 
imod Basaldelen og er forsynet med Længderibber, imel- 
lem hvilke sees 4—5 Rækker rundagtige Aabninger, Fig. 
10, c. Hele Piggen er 
halv gjennemsigtig Hud. 
omgiven af en temmelig tynd, 
Disse Pigge findes kun paa Ar- 
mens frie Rand, det vil sige paa den Del, der er imellem 
det før beskrevne Vinkelhjørne og Armens Spids; paa den 
indre Armrand findes ingen. 
I enhver Armyinkel sees en stor, lidt konkav, nøgen 
Kalkplade, der ganske indtager den hele Vinkel, har en 
triangulær Form, støtter sig til Siderne ved sine lange 
Udlobere til Adambulacralpladerne og indad til Mundpla- 
derne, Fig. 8, b., 
Fig. 8, c, der ere Forlengelser af 
Adambulacralpladerne, have paa deres afrundede, frie Rand 
Mundpladerne, 
Den norske Nordhavsexpedition. Danielssen og Koren  Asteroidea, 
All the calcareous plates are closely imbricate, and form 
regular series (fig. 3) which completely correspond with 
the previously described paxillar series. They, really, are 
merged in each other, so, that the entire abactinal dermal 
skeleton forms a complete calcareous armour, haying no 
tentacular pores (fig. 3). The intermerging, is, nearly every- 
where, so complete, that to separate the plates from each 
other, is not accomplished without difficulty. 
The actinal surtace is flat, and in this situation, the 
peculiar form of the rays becomes very prominent. There 
is no interbrachial space (fig. 2). 
The ambulacral furrow is not very wide, and is fur- 
nished with two series of cylindric suckers free from spic- 
ulæ, but with a broad sucker-disk. The furrow’s margin 
is furnished with two series of spines, of which, one is 
placed a little inside, and below the other (fig. 8, a). The 
spines of the inner series are the longest, but otherwise, 
the form is the same. They have a somewhat flattened 
appearance, but, really, form a demi-cylinder, which is 
broadest at the almost spatulate free extremity, and whose 
margin is erenate (fig. 9, a) whilst the narrower portion 
is round, and not hollow, and is furnished with an artic- 
ulatory surface (fig. 9, 0) articulating with a correspond- 
ing round knob on the adambulacral plate. These spines 
are furnished, longitudinally, with numerous series of minute 
nearly round perforations, and are clothed with an integu- 
mental covering. 
Beyond the furrow spines, and about the middle of 
the space between the ambulacral furrow and the margin 
of the ray, there is found, a series of exactly similar spines 
to those just described, except, that they are much longer 
(fig. 8, e). Finally, there is found on the margin of the 
ray, a fourth series of spines, which are different from the 
rest, and we shall designate them marginal spines (fig. 8,/. 
10). These are narrow at the basal part, which is round, 
and furnished with an articulatory surface (fig. 10, qa), and 
they expand in a leaf-shape towards the free extremity, 
upon which, five rather long points are situated (fig. 10,0), 
of which points, the two forming the angular apex points 
are the shortest. The margins of the leaf-formed part are 
somewhat curved inwards, producing a cavity, which is 
deepest down towards the basal part, and it is furnished 
with longitudinal ribs, between which, 4—5 series of round- 
ish apertures are seen (fig. 10, c). The entire spine is 
surrounded by a rather thin semi-transparent integument. 
These spines are found, only, on the free margin of the 
ray, that is to say, on the portion situated between the 
previously described angular apex. and the tip of the ray. 
None are found on the inner margin of the ray. 
In each brachial angle, a large, slightly concave, bare, 
calcareous plate is seen, which quite includes the whole of 
the angle, and has a triangular form, and it abuts later- 
ally by means of its long prolongations, on the adambula- 
ckal plates, and inwards, on the oral plates (fig. 8, 0). 
The oral plates (fig. 8, ¢) are prolongations of the 
adambulacral plates, and have, upon their free rounded 
13 
