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 papillae 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 7l°"0 Fahr. 



Subfamily Archastereos, 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 jSmall. Eays elongate, broad, tapering more or less abruptly. Interbrachial 

 angles acute. 



Supero-marginal plates confined to the margin, where they form a vertical wall. 



