3 staa paa hver Sidekant og I paa Hjørnet af Vinkelen 
ind til Furen. Fig. 4, å. 5, a. 
De 3 Sidepigge (undertiden findes dog 4 paa den ene 
Side) ere fladtrykte; deres frie Ende er temmelig skarp og 
takket. 
Den midterste Pig (Hjørnepiggen), der i Regelen er 
kortere end Sidepiggene, har en mere afrundet Form og 
bærer paa sin Ende en Slags Pedicellaria, der er fritstaa- 
ende og fæstet til Piggen ved en elastisk Stilk, hvori fin- 
des stærke Muskelfibre, der dirigere Bevægelsen, Fig. 5, 
D, Og & 
Den nævnte Pedicellaria rager et godt Stykke op over 
Furepiggene og strækker sig udover Ambulacralfuren. Den 
er langstrakt, 2”” lang; dens frie Ende, 0.81”” bred, er af- 
rundet, imedens Stilken, der er fæstet til Piggen, er temme- 
lig smal, næsten rund, 0.40”” tyk, Fig. 6. 
Pedicellariens Skelet dannes af en aflang, tyk Kalk- 
temmelig smal og bliver 
7, a. Strax ovenfor Ba- 
saldelen udvider Kalkpladen sig vingeformigt til den ene 
Side, Fig. 7, b, og faar sin største Udvidning paa dens 
øverste Del, hvor der iagttages en Fure, Fig. 7, c, som 
strækker sig nedover den indvendige, lidt konkave Rand (den, 
der vender mod Ambulacralfuren) til henimod dennes ne- 
derste Trediedel, Fig. 7, d, imedens den paa den udven- 
plade, som forneden er næ- 
sten rund, hvor den ender, Fig. 
dige, noget konvexe Rand, kun strækker sig lidt nedover 
dennes øverste Trediedel, Fig. 7, e. Kalkpladens Sidefla- 
der, Fig. 7, f, ere stærkt konvexe. 
Dette Kalkskelet er sammensat af et massivt Kalk- 
net, hvoraf enkelte Bjelker rage udover Randene og danne 
her kantede Pigge (Tænder), Fig. 7, g. 
Kalkskelettet er indesluttet af en tynd, halv gjennem- 
sigtig Membran, hvori hist og her yderst fine Kalkkorn 
ere henstrøede, Fig. 6. Membranen slutter tet til Kalk 
pladens Sider, medens den viger et godt Stykke fra dens 
udvendige Rand, saaledes at der imellem denne og Mem- 
branen bliver et lidet Rum, Fig. 6, a. 
Den før beskrevne Fure paa Kalkpladen er beklædt 
med en tyk, gulhvid Hud, der hvælver sig op over dens 
Rande og danner paa hver Side en stærkt fremstaaende 
Liebe, Fig. 6, b, som forlænger sig nedover paa Kalkpla- 
dens indyendige og udvendige Rand, saa langt som Furen 
strækker. Disse Læber have paa deres frie, hvælvede 
Rande, som ere noget bugtede, en liste, Fig. 6, c, der 
gjør Læberne paa dette Sted tykkere og fastere. Naar 
Læberne ere sluttede, opstaar en temmelig stor Hulhed, 
hvis Bund dannes af Kalkpladens Fure; vige Læberne fra 
90 
_ extends. 
are placed in a triangular form. There are 7 spines al- 
together, and one of them is placed at the apex of the 
triangle, next to the furrow; whilst, the other six spines 
are distributed, three, upon each of the containing sides 
(fig. 4, a, 5, a). 
The three lateral spines (occasionally, however, four 
spines may be observed upon one of the sides) are flat- 
tened, and their free extremities are rather acute, besides 
being ‘aculeated. 
The mesial spine (the apex spine) is, usually, shorter 
than the lateral spines, and has a more rounded form. It 
carries upon its extremity, a kind of pedicellaria, which 
is isolated, but secured to the spine by an elastic peduncle, 
in which strong muscular fibres, that serve to direct the 
movements, are seen (fig. b. 6, e). 
The pedicellaria referred to, projects considerably 
above the furrow spines, and extends across the ambulacral 
furrow. It is elongate, 2”” in length, and has a 
rounded free extremity, 0.81”” broad, whilst, the peduncle 
secured to the spine, is rather narrow, almost round, and 
0.40"" thick (fig. 6). 
The skeleton of the pedicellaria is formed of an ob- 
long thick calcareous plate, whose lower part is rather 
narrow, and becomes almost round at the termination (fig. 
7, a). Immediately above the basal part, the plate ex- 
pands to one side, in the form of a wing (fig. 7, b) and 
A furrow (fig. 7, ¢) 
the interior some- 
what concave, margin (that, facing towards the ambulacral 
furrow) until about the inferior third part (fig. 7, d), whilst, 
upon the exterior somewhat convex margin, it only ex- 
becomes widest in the superior part. 
occurs here, extending down over 
tends a little down over the superior third part (fig. 7, e). 
The lateral surfaces of the calcareous plates (fig. 7, f) are 
strongly convex. 
The skeleton is composed of a massive calcareous 
reticulation, of which, some rods project beyond the margins, 
and form, here, plane-sided spines (Teeth) (fig. 7, 9). 
The calcareous skeleton is enclosed by a thin semi- 
translucent membrane, in which, extremely minute calcar- 
eous grains, are here and there overstrewed (fig. 6). The 
membrane closes immediately to the interior margin of the 
calcareous plate, whilst, on the exterior margin, it is placed 
at a considerable distance from it, so, that between the 
membrane and the exerior margin of the plate, a small 
interspace is left (tig. 6, a). 
The previously described furrow on the calcareous 
plate, is covered with a thick yellowish-white integument, 
which becomes swollen up, over and above the margins, 
forming on each margin, a strongly protuberant labia (fig. 
6, b) which extends downwards, on the exterior and inter- 
ior margin of the calcareous plate, as far as the furrow 
These labiæ, have, upon their free arcuate marg- 
ins, which, also, are somewhat curved; a fillet (fig. 6, ©), 
which causes the labize, to become in this situation, thicker 
and firmer. When the labiæ are closed, a tolerably large 
