'688 
Proceedings of the Royal Irish Academy. 
3. Astropecten irregularis, Linck. 
Depth 345 fathoms. 
Depth 24 fathoms. 
Depth 50 fathoms. 
4. Fsilaster Andromeda (Miiller & Troschel), Sladen. 
? locality. 
5. Luidia ciliaris (Philippi), Gray. 
Depth 52 fathoms. 
6. Luidia Sarsii, Diiben & Koren. 
Depth 5 fathoms. 
7. Pentagonaster halteatus, n. sp. (Plate xxv., figs. 1-5.) 
Eays five. E = 22 mm. ; = 13 mm. ; E, = 1-69 r. The 
minor radius is thus in the proportion of 59 per cent. 
General form flat and moderately thick. Marginal contour penta- 
gonoid with lunate sides, having the radial angles slightly produced, 
and obtusely rounded at the extremity. Interbrachial arcs forming a 
wide, regularly sweeping curve. Margins rather thick and almost 
equally rounded actinally and abactinally. Abactinal area slightly 
inflated in the central and radial regions, and slightly depressed in 
the interradial areas near the margin. Actinal area subplane, with 
slight depressions in the interradial areas. 
The abactinal area is covered with rather large hexagonal plates, 
those in the median radial line being larger than the others, excepting 
only the basal plates, and two or three adjacent plates in the inter- 
radial areas, which are subequal to the largest in the median radial 
series. All the plates diminish in size as they approach the margin. 
The abactinal plates do not quite reach the extremity of the ray in 
consequence of the junction of the penultimate and antepenultimate 
supero-marginal plates of the two sides of the ray in the median radial 
line. The surface of the plates is covered with large, low, uniform 
hemispherical granules, which are not crowded so as to actually touch, 
or at any rate modify the form of the separate granules. The tabulum 
is surrounded by a single series of similarly low granules, the outer 
edge of which is sharply cut in conformity with the contour of the 
hexagon, as if the latter had been "dressed" with a knife. The 
abactinal surface of the tabula in the radial regions is slightly convex. 
Occasional plates (but very few) bear a single small excavate pedicellaria, 
with two short spatulate jaws. 
