610 
THE VOYAGE OE H.M.S. CHALLENGER. 
moderately long cylindrical rigid rays, which are entirely encased by the smooth marginal 
plates, the form of the ray bearing a fanciful resemblance to an elongated Belemnite. 
“ In the deep water off the eastern coast of the 
United States, a very rich assemblage of forms was met 
with, Station 46 being especially remarkable for its 
varied Asterid fauna. Here at a depth of 1350 fathoms 
are Brisinga, Cribrella, Zoroaster , Porcellanaster, and 
the three Archasterid genera, Pontaster, Parar chaster, 
and Plutonaster. Pontaster is a genus established 
for the reception of Archaster tenuispinvs, Diiben 
and Koren, and its allied species, whose structure 
does not admit of their being classed along with 
Archaster typicus, Muller and Troschel, which by reason 
of priority naturally stands as the type of Archaster, 
sensu stricto. 
“ Plutonaster has a comparatively large flat disk, 
with elongate and more or less rigid rays. The marginal 
plates are broad, and form a well-rounded margin ; both 
series are granulated, the superior being devoid of large 
spines, but the inferior may have one small more or less 
rudimentary spine. The abactinal area is covered with 
small closely packed pseudo-paxillse ; papulae are distri- 
buted over the whole area, and the abactinal plates at 
the sides of the rays are arranged in oblique transverse 
series. The actinal interradial areas are large, with 
well-defined plates in regular columns, decreasing in 
breadth towards the margin. Armature of the adambu- 
laeral plates in longitudinal series, parallel with the 
furrow ; several of the outer series usually granuliform. 
No pedicellariae. 
“ Pctrarchaster (fig. 204) is a remarkable form with 
a small disk and very long, tapering, flexible rays. 
Marginal plates more or less suboval or subtriangular, 
elongate in the direction of the ray, and confined to the 
margin entirely ; each with a prominent boss. The 
supero-marginal series with one long cylindro-conical 
spine, the infero-marginals with one or more similar 
spines. The general surface of the plates of both series is nominally naked, or only with 
minute isolated spiniform granules, A large odd interradial marginal plate present at 
Fig. 204 . — Pararchaster jiedicifer, Sla/lcn. 
Abactinal aspect. Natural size. 
