REPORT ON THE ASTEROIDEA. arg 
group, which in posture fancifully resembles the hand when held slightly hollowed as if to 
catch a ball. (2.) A single, conical, tapering, sharply pointed spine, nearly as long as the 
short lateral spines, stands on the actinal surface of the plate. There are also on the 
surface of the plate two or three very small spinelets or thornlets on both sides of this central 
spine placed at each end of the plate, in such a way as to appear to form a continuation 
of the marginal series above described ; and there may be one or two small spinelets, equal 
in size to these lateral ones, or a trifle larger, near the base of the central spine. Beyond 
these there are no other spinelets on the adambulacral plates. The scoop-like groups of 
the marginal series extend over the furrow, and touch the corresponding groups of the 
opposite side, widely separating the pairs of ambulacral tube-feet. 
The mouth-plates are comparatively large and broad, and the united pair are con- 
spicuous in consequence of their subtubercular character, and of a well-defined depression 
at the outer extremity of the pair, in which no plate is present between them and the 
marginal plates. The free margin of the united pair is well rounded and more tumid 
laterally than a semicircle ; its armature consists of six spinelets for each plate, the inner 
one being twice as large as the others, which are nearly equal in length; there is thus a pair 
of prominent but short spinelets at each mouth-angle directed horizontally over the buccal 
membrane, whilst the remaining five mouth-spines of each plate maintain in their posture 
more or less of the scoop-like character of the adambulacral armature. On the actinal 
surface of the plates there is one secondary mouth-spine similar in character to, but 
scarcely as large as, the actinal spines on the adambulacral plates ; a lineal series of about 
six small, uniform, thorn-like spinelets runs parallel to the median suture; and three or 
four similar spinelets also form a lineal series behind the secondary mouth-spine. 
No actinal intermediate (ventral) plates of any kind are present; and the marginal 
plates are contingent on the adambulacral plates throughout. The ambulacral tube-feet 
have a small, but definite and rounded, knob-like tip. 
One large, compound pedicellarian apparatus is situated in each interradium, placed 
between the two innermost infero-marginal plates. It is of oval form, with the length 
about equal to half the breadth of the marginal plates, and its margin is beset with ten to 
twelve small pointed spinelets directed horizontally from the two sides in order to close 
over a central cavity. This organ is placed close to the inner margin of the marginal 
plates, and encroaches equally upon each of the two plates. A similar pedicellarian 
apparatus occurs in the lateral vertical wall of three of the interbrachial arcs, situated 
between the two innermost supero-marginal plates. No other pedicellarize are present. 
The anal aperture is subcentral and very distinct ; and the spinelets of the surrounding 
paxille, which form its margin and close over the aperture, are sensibly more robust than 
any of the others. 
The papule are confined to a small group, which forms a definite papularium at the 
base of each ray, and there are not more than six papulew in each, and sometimes only 
(ZOOL. CHALL. EXP.—PART LI.—1887.) 8 
