REPORT ON THE ASTEROIDEA. Of 
6. Dytaster biserialis, n. sp. (Pl. X. figs. 3'and 4; Pl. XIII. figs. 3 and 4). 
Rays five R=44mm.;7r=10mm. R<4-5r. Breadth of a ray near the base, 
8°5 mm. 
Rays elongate, narrow and tapering; of a more or less rigid habit, comparatively 
thick, subquadrate in section, with vertical lateral walls. Interbrachial arcs widely 
rounded. Abactinal surface plane and level. Actinal surface of disk convex, prominent 
at the mouth-angles, and sloping thence to the margin and slightly along the ray. 
The paxillze of the abactinal surface are very small, simple, and crowded, normally 
composed of four short papilliform or almost granuliform spinelets ; often three only are 
found, and five are but rarely present. They are devoid of a central spinelet or granule. 
On the outer half of the ray the paxille are quite microscopic, more widely spaced, and their 
simplicity is more evident. On the disk and at the base of the rays a great number of 
paxillee are metamorphosed into pedicellariz, the three or four constituent spinelets being 
much enlarged, modified in form, and so placed that the tips are brought together, thus 
forming a large and powerful trivalvate or quadrivalvate pedicellaria. These form a con- 
spicuous feature on the abactinal area, and their distribution amongst the paxille is 
irregular. The pedicle of the paxilla consists of a general tubercular convexity of 
the plate. 
The supero-marginal plates, twenty-eight in number from the median interradial line to 
the extremity, form a narrow and more or less bevelled margin to the rays, the breadth being 
less than the height or the length, and the latter dimension is slightly the greatest. The 
series of plates form a continuous level surface, uninterrupted by individual convexities. 
Each plate bears a short, conical, but blunt spinelet, little more than an elongate tubercle, 
placed on the curved part of the plate and directed at an angle outwards. The surface 
of the plate is covered with very minute, widely spaced conical granules. 
The infero-marginal plates correspond exactly to the superior series, each being directly 
beneath and opposite its companion plate; their line of suture is consequently straight. 
The breadth on the inner part of the ray is a little greater than the length, but on the 
outer part the proportions are reversed. ach plate bears a single short spinelet similar 
in size and character to those on the supero-marginal plates, or perhaps a shade longer ; 
and the surface of the plate is covered with similar minute, conical, widely spaced granules. 
The adambulacral plates are long and very narrow, and with the furrow margin only 
slightly convex. Their armature consists of :—(1.) A furrow series of eight short, cylin- 
drical spinelets, the outermost on each side being shorter than the rest. (2.) Immediately 
behind the furrow series is a lineal series of six similar but rather smaller spinelets, 
running parallel to the median line of the ray. On the outer part of the ray the 
spinelets of both series become extremely short. No other spinelets or granules are 
present on the plates. 
The mouth-plates are large, elongate, narrow, and the united pair are prominently 
