590 



THE VOYAGE OF H.M.S. CHALLENGER. 1 



Chorological Synopsis of the Species. 



1. Calvasterias stolidota, n. sp. (PI. CI. figs. 3 and 4; PL CIII. figs. 11 and 12). 



Pvays five. E = 44 mm. ; r = 11 mm. E=4r. Breadth of a ray at the base, 13 - 5 mm. 

 Kays rather short, tapering slightly from the base to the extremity, which is obtusely 

 pointed. Abactinal surface convex and arched, the lateral wall being nearly vertical. 

 Actinal surface plane, forming an angular junction with the lateral wall. In the present 

 condition of the specimen the rays are curved downward. Interbrachial arcs acute. A 

 more or less clearly defined channel occurs upon the disk in the wrinkles of the membrane 

 in the median interradial lines. 



The whole abactinal surface is covered with a somewhat puffy membrane, very clammy 

 and unpleasant to the touch, marked with constrictions or wrinkles which pass between 

 the papular areas. Midway on the ray in the median line the broad tips of a few obtuse 

 but isolated spinelets may be seen protruding through the membrane, but they are 

 scarcely noticeable. The papulae are arranged in compact little groups of about five 

 or six in each ; the groups are well spaced and fall into six more or less regular longitudinal 

 lines. A few small pedicellariae may be present in the neighbourhood of the papulae of 

 the outer two rows on each side. 



The armature of the adambulacral plates consists of a single robust, cylindrical, 

 obtusely-tipped spinelet, the series of which forms a regular longitudinal line along the 

 ray. At the base of these spines, on the margin of the ambulacral furrow, are a few 

 short, robust, forficiform pedicellariae. The actinal plates, which form the margin of the 

 ray, and are probably the representatives of infero-marginal plates, bear an oblique series 

 of two or three equal, short, robust, obtuse spinelets. In the interspace between these 

 plates and the adambulacral plates, which is narrow, are large isolated papulae, and 

 between these may be a spinelet intermediate in size between those on the adambulacral 

 plates and the marginal plates, and these form an irregular series which, from their 

 position, might at first sight be counted with either one series or the other ; they are 

 found, however, on examination to be not attached to the adambulacral plates. Above 

 the infero-marginal plates just described, in the vertical wall of the ray, is a rather wide 



