267 
the snckels of llie two columns in each radial area are quite distinct 
tVuin each other; the intcrradial ridges on the proximal portion of the 
centrodorsal are low, rounded and short 
d' basals separated from the centrodorsal at the interradial angles (Fiji) wyvillii 
d- basals everywhere in contact with the centrodorsal (Moluccas and 
Phil i lupines) uilcatus 
c- the 10 columns of cirrus sockets are closely crowded on a small sharply 
conical centrodorsal ; the interradial ridges on the proximal portion of 
the centrodorsal are high and sharp 
d' centrodorsal with the sides more nearly parallel at the base than 
further out, and much longer than broad at the base (Carib- 
bean Sea) halanoides^) 
d- centrodorsal sharply conical, very slightly longer than broad at the 
base (western coast of I rela nd) hclga 
zae 
I. Atelecrinus sulcatiis A. H. Clark. 
A. II. Cl,.\RK. Notes from the Leyden Museum, vol. 34, 1912, p. 152. 
Stat. 85. o°36'.5S., II9°29'.5E. Makassar Straits. 724 Metres, i Ex. 
The centrodorsal is sharply conical, 3 mm. broad at the base and 4 mm. in vertical 
height. The cirrus sockets are arranged in ten columns four, more rarel)' five, to a column ; 
the two columns of each radial area are close together; the columns of adjacent radial areas 
are separated l)y shallow furrows which basally are in width nearly equal to the diameter of 
the adjacent cirrus sockets, but become gradually narrower distally ; the interradial .separation 
of the columns of cirrus sockets is always somewhat greater than the 
midradial separation. Each cirrus socket is bordered proximally and 
laterally by a horseshoe-shaped rim which proximally scarcely rises above 
the general surface of the centrodorsal, but on either side .stands out as 
high ridge so that in lateral view the sides of the centrodorsal appear 
strongly serrate, the longer side of the teeth being gently convex, roughly 
parallel with the donsoventral axis, the shorter slightly concave, at right 
angles to this axis. The ridofes on either side of the cirrus sockets 
gradually increase in thickness distally, but terminate rather abruptly just 
after attaining their maximum height and thickness, so that the border 
of the cirrus sockets distal to them is not raised above the general 
surface of the centrodorsal. The basal outline of the centrodorsal as 
viewed dorsally is pentagonal, each side of the pentagon being slightly 
Fig. 16. 
L.iteral view of a specimen 
of Atelecrinus sulcalus from 
"Albatross" Stat. 5619. X 3- 
and evenly concave ; five well marked rounded interradial ridges are (Courtesy of the f. s. Na- 
, tional Museum). 
present which slowly decrease in height and disappear at about the distal 
border of the first cirrus sockets. These ridges mark the angles of the pentagon when the 
l) Synonyms ciibensls P. H. Carpenter and potirtat'csi A. H. Clark. 
