568 THE VOYAGE OF H.M.S. CHALLENGER. 
A. Asterias rubens group: ASTERIAS vera. 
1. Asterias vesiculosa, n. sp. (P]. XCIX. figs. 1 and 2; Pl. CHI. figs. 9 and 10). 
Rays six. R=8lmm.; r=16mm. R>5,r. Breadth of a ray at the base, 15 to 
16 mm.; breadth about midway between the disk and the extremity, 9 mm. 
Rays elongate, subdepressed, tapering from the base to the extremity, the outer part 
of the ray being narrow and rather attenuate. Disk subdepressed, only slightly inflated ; 
abactinal surface of the rays slightly convex, also slightly convex at the base on the actinal 
surface, the disk being marked with depressions in the actinal interradial lines. Inter- 
brachial arcs acutely angular. 
The abactinal plates are entirely masked. The whole area is beset with isolated, widely 
spaced, short, robust, obtuse spinelets, each of which is encircled by, and appears to pro- 
trude through, a widely expanded puffy vesicle. Occasionally one or more rather large 
pedicellarize may be imbedded. No definite order of arrangement can be detected in the 
disposition of the spinelets. The interspaces betw2en the vesicles are closely crowded 
with numerous large papulz, amongst which pedicellariz are occasionally interspersed, 
and sometimes the latter are borne on a vesicle resembling in miniature that of the 
spinelets. Viewed with the naked eye the whole abactinal surface has a coarse, irregularly 
granular and studded appearance. 
The armature of the adambulacral plates consists of two short, robust, cylindrical, 
slightly tapering, obtuse spinelets, which form two regular longitudinal rows. At the base 
of the innermost spine, and quite within the furrow, are numerous very large forficiform 
pedicellariz. External to the adambulacral plates is a rather wide space covered with a 
thick, puffy, wrinkled membrane, through which protrude a single longitudinal series of 
widely spaced and rather large papule, and this space is bounded at the margin of the 
actinal area by a longitudinal series of plates (probably the representatives of infero- 
marginal plates) upon which are borne one or usually two diagonally placed small 
spinelets, almost hidden in an expansive vesicle beset with isolated pedicellariz. Above 
this series of infero-marginal plates is a wide area which occupies the lateral wall of 
the rays, covered with thick wrinkled skin, punctured with rather numerous papule, and 
bearing, at least near the base of the rays, large forficiform pedicellarie. It is bounded 
superiorly by a regular longitudinal series of plates—the representatives of the supero- 
marginal series—upon each of which is borne a single rather small spinelet, surrounded 
by a large, widely expanded vesicle in which are imbedded from three to five pedicellariz. 
Here and there upon the abactinal surface and elsewhere may be seen isolated and very 
large forficiform pedicellarize usually on a vesicular base. 
The madreporiform body, which is situated about midway between the centre of the 
disk and the margin, has its surface grooved with fine convoluted striations. 
