116 THE VOYAGE OF H.M.S. CHALLENGER. 
series is a line of three short papilliform spinelets parallel to the furrow, rather wide apart, 
and of which the two outside spines often appear as if they belonged to the furrow series. 
Behind these is a second and similar longitudinal series of three spines, the middle one 
being often longer than the others; and these are followed by three or four smaller papille, 
completing the armature of the plate. The furrow series have a decidedly palmo-radiate 
appearance, and the spines of the external series have a tendency to incline at a slight 
angle towards the next adjacent adambulacral plate. 
The actinal interradial areas are comparatively small and are ornamented with short 
papilliform granules, which appear to be arranged rather widely apart round the margins 
of the plates; sometimes one or more papillze are present in the middle of this circlet, 
and occasionally one is slightly larger than the rest. Consequent on this arrangement 
the individual plates are more or less defined, but are not distinct ; the spinulation is by 
no means crowded. 
The pair of mouth-plates form a subelliptical or widely fusiform outline. Hach plate 
bears a straight line of about ten short papilliform spinelets running parallel to the 
median suture, and a similar number on the opposite margin of the plate which con- 
sequently form a curved series ; one or two additional spinelets may be present on the 
intermediate area of the plate. ‘The marginal spines are about equal in length to 
the adambulacral spines, but are rather more robust. 
Colour in alcohol, a yellowish ashy grey. 
Locality.—Station 49. Off the coast of the United States, south of Halifax, Nova 
Scotia. May 20, 1873. Lat. 43° 3’ 0” N., long. 63° 39’ 0” W. Depth 85 fathoms. 
Gravel and stones. Bottom temperature 35°°0 Fahr. ; surface temperature 40°°5 Fahr. 
Remarks.—This species is allied in many respects to Pseudarchaster tessellatus. The 
rays, however, are more tapering, the abactinal area is less inflated, the paxille though 
smaller are composed of more numerous spinelets, the marginal border formed by the 
supero-marginal plates is broader, the covering of the infero-marginal plates is more 
squamiform, and the definite single line of pointed spinelets which occurs in Pseudarchaster 
tessellatus is not present. There is no large prominent spine on the outer part of the 
adambulacral armature as in the South-African species. 
Genus Aphroditaster, Sladen. 
Aphroditaster, Sladen, in Narr. Chall. Exp., 1885, vol. i. p. 612. 
Disk rather small. Rays elongate, tapering. Interbrachial arcs well rounded. 
Marginal plates broad, forming a well-rounded margin; intermediate abactinal area 
narrow and sunken. Supero-marginal plates with rounded granules, infero-marginal plates 
with small, uniform, conical-pointed, adpressed (squamiform?) spinelets. No prominent 
spines on either series. 
