Sladen — Echinodermata from the S. W. Coast of Ireland. 691 
lunate pentagonoid or stellato-pentagonal, with the radial angles 
produced, and tapering to an acute extremity ; interbrachial 
arcs regularly rounded, the curve being that of a part of a circle. 
Margins rather thin, bevelled abactinally, more abruptly rounded 
actinally. Abactinal area capable of slight inflation. Actinal area 
plane. 
The abactinal area is covered with small subcircular plates, closely 
placed, only the three medio-radial series of plates being separated by 
papulae. The abactinal plates do not extend to the tip of the ray, the 
three supero-marginal plates preceding the ultimate, uniting with the 
corresponding plates on the other side of the ray in the median 
radial line. The margin of the tabulum is surrounded by a series of 
small, rather broad granules, moderately spaced, and the surface of the 
tabulum is covered with a small, uniform, well spaced, hyaline 
granulation. I have not detected the presence of pedicellarise upon 
any of these plates. 
The supero-marginal plates, which are eight in number, counting 
from the median interradial line to the extremity, form a well-defined 
border to the abactinal area, of uniform breadth throughout. The 
plates near the interradial line have their length rather greater than 
their breadth, but these proportions gradually become equalized, 
when the fourth or fifth plate from the median interradial line is 
reached ; and the antipenultimate and penultimate plates have the 
breadth slightly greater than the length. The ultimate plate is 
small and wedge-shaped, with the apex directed towards the median 
radial line. The abactinal surface of the supero-marginal plates is 
slightly convex, which causes each plate to be distinctly defined. A 
few small uniform hemispherical granules are present on the lateral 
wall of the plate, which rub o£E with the slightest touch. "Whether 
the whole surface of the plate was during life covered with similar 
granules I am unable to say, but I am inclined to think that such was 
not the case. A few large, isolated, irregularly placed pits are present 
on the surface of the plate, more numerous near the junction of the 
abactinal and lateral areas. A series of small granules surrounds the 
margin of the plate. The odd terminal plate is conical and larger 
than the ultimate supero-marginal plates ; it bears at the apex a 
robust, obtuse, short, papilliform spine. 
The infero -marginal plates are eight in number, counting from the 
median interradial line to the extremity. The three plates on each 
side of the median interradial line have the length subequal to the 
breadth, but in all the succeeding plates the length is greater than 
