612 
THE VOYAGE OF H.M.S. CHALLENGER. 
“At Stations 44 -and 45 Dytaster is associated with Pontaster and P arar chaster ; at 
the former Station in company with Phoxaster, and at the latter with Porcellanaster 
(fig. 205). Porcellanaster is found in the South Atlantic between Tristan da Cunha and 
the Cape of Good Hope at a depth of 2550 fathoms (Station 137) ; and at Station 346, 
north of Ascension, at 2350 fathoms, is the very remarkable allied genus Styracaster 
(fig. 206). In this form the rays are long and attenuate, with the supero- marginal plates 
meeting in the median dorsal line so as to encase the ray, and bearing long robust 
cylindro-conical spines which form a single series along the median dorsal line. The 
actinal interradial areas are paved with thin smooth imbricated plates arranged in 
columns ; and the ambulacral furrows are narrow and more or less enclosed. 
“At Station 78, in a depth of 1000 fathoms, associated with Pontaster , is an elegant 
form, Aphroditaster, the type of a genus especially interesting on account of its inter- 
mediate character between the Archasteridse and Goniasteridse. The disk is rather small, 
with the rays elongate and tapering ; and the interbrachial angle well-rounded. Marginal 
plates broad, forming a well-rounded margin ; intermediate abactinal area narrow and 
sunken. Superior marginal plates with rounded granules, inferior series with small 
uniform conical, pointed, adpressed spinelets. No prominent spines on either series. 
Abactinal area with large oblong hexagonal paxillse, the major axis in the direction of the 
axis of the ray ; a conspicuous medio-radial series larger than the rest, each of these 
paxil he being well spaced from its neighbours in the series. Papulae regularly distributed. 
Abactinal plates arranged in lines parallel with the axis of the ray. Ventral areas small, 
plates with small conical-pointed spinelets similar to those on the infero-marginal plates. 
Armature of the adambulacral plates in two longitudinal series parallel with the furrow. 
A post-ad ambulacral series of plates present with fascioles ( sensu A. Agassiz) at the margins 
obliquely transverse to the axis of the ray. Madreporiform body small. No pedicellarise. 
“ At Stations 3 (1525 fathoms), 106 (1850 fathoms), and south of the Equator at Station 
125 (1200 fathoms), were dredged representatives of a very handsome Goniasterid genus, 
Nymphaster. The disk is large and flat, with more or less elongate, slender, tapering 
rays, almost square in section. The marginal plates form a broad border to the disk, and 
may either unite along the median line of the ray or admit a single series of medio-radial 
plates. The marginal plates are granulated and bear no spines. The abactinal area of the 
disk is covered with large and regularly arranged hexagonal tabulated paxillse, those in 
the radial area well separated, and each usually furnished with a sunken pedicellaria. 
Large entrenched pedicellarise are frequently present on the marginal plates. Ventral 
plates well-defined, covered with uniform granules, and with occasional pedicellarise. 
Adambulacral armature arranged in longitudinal series. 
“At Station 73, at a depth of 1000 fathoms, in company with Plutonaster, is an interest- 
ing genus, Glyptaster , which seems to unite the characters of Zoroaster and Stichaster. 
Glyptaster has a small disk and comparatively long, subrigid, tapering rays. The disk 
