120 THE VOYAGE OF H.M.S. CHALLENGER. 
pseudo-fascioles, obliquely transverse to the furrow. These are formed of six to eight 
short, flattened, truncate papille or spinelets of equal length, placed in lineal series along 
the adoral and aboral margins of the plate, and directed towards the corresponding series 
of the adjacent plate ; the intermediate area of the plate being occupied by several more 
or less regularly parallel series of papilliform granules, standing perpendicularly, which are 
short, subconical, and not flattened. The innermost plates of the series are subtriangular 
and meet in the median interradial line, their pseudo-fasciole running in continuation of 
the suture of the mouth-plates. Some of the pseudo-fascioles do not correspond to the 
junctions of the adambulacral plates. The remaining actinal intermediate plates are 
comparatively small, and decrease in size as they approach the margin; they are some- 
what indistinctly marked off into columns by the suture lines. The plates bear rather 
widely spaced, short, cylindro-conical, papilliform granules or thornlets, similar to those 
on the infero-marginal plates but not flattened ; their posture is, however, slightly inclined 
to the plate and directed outward. All are fairly uniform in size, though here and there 
one slightly larger than the rest may be seen with a magnifying glass, but is scarcely 
noticeable with the naked eye. 
The mouth-plates are small and rather inconspicuous. The margin which falls in the 
ambulacral furrow bears a lineal series of about ten spinelets similar to the furrow series 
on the adambulacral plates ; four or five short cylindrical spinelets are near the margin 
adjacent to the adambulacral plate and form an angle with the series just mentioned ; and 
a lineal series runs parallel to the margin which unites with the companion mouth- 
plate. Sometimes one or two additional spines may be present on the outer part of the 
plates and some irregularity may occur in the disposal of the spines there, which causes 
the spinulation of that part of the plate to assume a rather grouped appearance. 
Colour in alcohol, ashy white on the marginal plates, with the paxillar area of a 
darker dirty grey ; under side rather more yellow in tint. 
Locality.—Station 78. Between the islands of San Miguel and Santa Maria (Azores). 
July 10,1873. Lat. 37° 26’ 0” N., long. 25°13’ 0” W. Depth 1000 fathoms. Volcanic 
mud. Surface temperature 71°°0 Fahr. 
Subfamily ArcHASTERIN”, Sladen, 1886. 
Genus Archaster, Miiller and Troschel (1840), emend. Sladen, 1886. 
Archaster, Miiller and Troschel, Monatsber. d. k. Akad. d. Wiss. Berlin, 1840, p. 104; System der 
Asteriden, 1842, p. 65. 
Disk small. Rays elongate, broad, tapering more or less abruptly. Interbrachial 
angles acute. 
Supero-marginal plates confined to the margin, where they form a vertical wall. 
