REPORT ON THE ASTEROIDEA. 483 



rendering them inconspicuous ; they have, however, the peculiarity of closing the space 

 between their own and the next aboral comb at the margin of the furrow. The aperture- 

 papillae are small and sublanceolate in form, hidden in the general membrane, excepting 

 their adoral side, which alone is free, and closes the aperture, shutting close up to the 

 next aboral actino-lateral spine. 



The mouth and parts surrounding ic are much sunken — a feature further emphasised 

 by the deep wall of the continuous marginal fringe. The mouth-plates are elongate, with 

 their aboral extremities produced into a rather prominent peak, suggestive of that in 

 Hymenaster. About five mouth-spines are borne on the outer margin of each plate, the 

 innermost much longer and more robust than the others, all webbed together and forming 

 an elegant marginal comb conformable to the contour of the plate. The innermost spines 

 of the two adjoining plates stand close together, but are not united by web. On the 

 superficies of each plate, and nearer the mouth than midway, is a long, robust, cylindrical, 

 rapidly tapering secondary spine, standing isolate and perpendicular, covered with mem- 

 brane, but with no web-attachments. 



The actino-lateral spines are short and robust, not more than one-third longer than the 

 outermost spine on the adambulacral plates, and tapering only very slightly. They are 

 united by a close fibrous web, the margin of which and the tips of the spines (as well as the 

 tips of the spinelets in the transverse adambulacral combs) are tipped with dark purple. The 

 lateral fringe thus formed stands perpendicular on the margin of the furrow ; and the spines 

 comprising it would at first sight be thought to belong to the comb-series. The fringe of 

 the adjacent sides of two neighbouring rays is merged together at their adoral extremity, 

 forming a continuous fringe, which runs close past the aboral end of the mouth-plates. 



Localities.— Station 189. In the Arafuia Sea. September 11, 1874. Lat. 9° 36' 0" S., 

 long. 137° 50' 0" E. Depth 25 fathoms. Green mud. Surface temperature 79° - Fahr. 



Station 187. Off Booby Island, Torres Strait, September 9, 1874. Lat. 10° 36' 0" 

 S., long. 141° 55' 0" E. Depth 6 fathoms. Coral mud. Surface temperature 77°'7 Fahr. 



Remarks. — This remarkably handsome form may be distinguished at the first glance 

 from all other species. In fact the superficial differences are so striking that I was at first 

 disposed to accord it subgeneric rank ; the structure of the supradorsal membrane, of the 

 adambulacral armature, and of the actino-lateral fringe appearing to justify that step. 

 Further study has, however, scarcely borne out the morphological importance which I was 

 inclined to place upon these structures, and I now merely mention the circumstance as 

 indicative of the characters by which the species may be readily distinguished. 



Genus Marsipaster, Sladen. 

 Marsipaster, Sladen, Journ. Linn. Soc. Lond. (Zool.), 18S2, vol. xvi. p. 202. 

 Form depressed. Marginal contour pentagonoid. Abactinal area flatly convex. 

 Actinal area plane. 



