202 ME. W. PEECt SLADE¥ OK THE 



aboral side, which alone is free, which closes the aperture, shut- 

 ting close up to the next aboral actino-lateral spine. 



The mouth and parts surrounding it are much sunken — a 

 feature further emphasized by the deep wall of the continuous 

 marginal fringe. Mouth-plates elongate, with their aboral ex- 

 tremities 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, 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, pointed secondary spine, standing isolate and 

 perpendicular, covered with membrane, but with no web-attach- 

 ments. 



Actino-lateral spines short and robust, not more than one third 

 longer than the outermost ambulacral spine, 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 

 ambulacral spinelets in the transverse combs) are tipped with 

 dark purple. The lateral fringe thus formed stands perpendi- 

 cular 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. 



Station 189. Lat. 9° 36' S., long. 137° 50' E. Depth 

 25-29 fms. ; mud. Also ofi" Booby Island. 



Maesipasteb, n. gen. 

 Form depressed, marginal contour pentagonoid, dorsal area flatly con- 

 Vex, aetinal area plane. Supradorsal membrane an irregularly developed, 

 somewhat spongiform tissue. No muscular fibrous bands. No spicules. 

 Paxillse with moderately expanded crowns composed of a great number of 

 fine, long, hair-like spinelets (15-30), their extremities protruding freely 

 through the membrane. Paxillse invested with a well-developed mem- 

 branous envelope. Ambulacral spines webbed together, forming trans- 

 verse combs ; spinelets more or less horizontal in position, overspanning 

 the furrow. Mouth-plates with one secondary surface-spine, connected 



