REPORT ON THE ASTEROIDEA, 405 
margin of the disk, and its margin prevents the meeting of the lateral series of abactinal 
plates next the median radial series of the two adjacent rays. ‘The striations are fine and 
sharply convoluted, the general trend being more or less regularly centrifugal. The primary 
apical plates on the disk are distinctly discernible. 
The anal aperture is excentric in position, and is closed by a few small, valve-like, 
scutiform plates. 
Colour in alcohol, a light brownish grey on the abactinal surface, mottled with darker 
patches of brown here and there, and with a number of the papular areas marked with a 
much darker shade of brown, the papular areas generally being darker than the plates and 
dissepiments, which gives a very ornate character to the species. The actinal surface is 
a bleached white. 
Locality—Station 186. In Torres Strait, off Cape York. September 8, 1874. Lat. 
10° 30’ 0” S., long. 142° 18’ 0” E. Depth 8 fathoms. Coral mud. Surface temperature 
77°°2 Fahr. 
Remarks.—The nearest ally of this species appears to be Ophidiaster granifer, Liit- 
ken, but it is well distinguished by the six rows only of papular areas, by the great size 
of these and the numerous papule, by the character of the granulation and the presence 
of the large conical tubercles, by the small dumpy pedicellariw, and by the peculiar form 
of the outer spinelets on the actinal surface of the adambulacral plates. The triple series 
of spinelets in the armature of the adambulacral plates recall the same intermediate 
character between Ophidiaster and Linckia as already noted in Ophidiaster granifer by 
Perrier.’ 
5. Ophidiaster helicostichus, n. sp. (Pl. LXIX. figs. 5-7). 
Rays five. R=130 mm.; r=12°5 mm. R=10-47. Breadth of a ray near the 
base, 13°5 mm. 
Rays elongate and tapering gradually to the extremity. Disk small and slightly 
convex. Interbrachial arcs subacute. 
The abactinal and marginal plates, which are arranged with great regularity, form seven 
longitudinal series. The plates of the median series are rather larger than the others, which 
are small in comparison to the size of the starfish, and all are united by broad, sharply de- 
fined dissepiments. The surface of the plates is very slightly convex, and is covered with a 
small, rounded, closely packed, and nearly uniform granulation, excepting round the margin 
of the papular areas where it is extremely small. None of the plates bear large granules 
or tubercles. Smal] entrenched pedicellarie of the figure-of-eight form are occasionally 
present on the plates near the margin of the papular areas, but are not numerous. 
The papular areas, which are large and rather deeply sunken, are subcircular or oval 
1 Révis, Stell. Mus., p. 128 (Archives de Zool. expér., 1875, t. iv. p. 392). 
