284 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. 



not clearly marked off. Abactinal surface of rays high, rounded ; actinal surface 

 somewhat flat. Distal end of ray upturned, so that ambulacral furrows terminate 

 on abactinal surface. Supradorsal membrane rather thin with no sign of reticula- 

 tions. Spiracula small but very abundant all over abactinal surface. Paxillae 

 high with numerous spines (8-10 or more) of approximately equal size. About 

 30 of the paxillae have the spines longer and stouter than the others, and these 

 push the membrane up into more or less conspicuous points or ridges, which are 

 irregularly scattered and give the abactinal surface a rough, almost warty appear- 

 ance. Apparently there are no other calcareous particles in the membrane. Os- 

 culum large, surrounded by about 50 closely webbed long spines, which nearly 

 close it. Ambulacra of moderate width ; feet in two rows. Adambulacral plates, 

 each with six (near the mouth there may be seven) spines, the innermost much 

 the smallest, the outermost longest ; as the innermost is situated on the inner 

 aboral corner of the plate and the others are on its adoral side, the series is 

 distinctly curved, with the concavity away from the mouth ; all the spines are 

 united to each other and to the actino-lateral spine by a membrane which reaches 

 nearly to their free ends, but from which they project distinctly. Actino-lateral 

 spines short, only about half as long again as the outermost adambulacral spine; 

 as they are approximately equal except at tip of ray, the actino-lateral "fringe" 

 is narrow and nearly parallel-sided, and is thus completely concealed from above ; 

 aperture-papilla small, free only along its aboral edge. Mouth-plates large, de- 

 cidedly elevated at their aboral ends, where they terminate in a conspicuous point ; 

 the points of the. adjacent plates are closely appressed, so there is only one point 

 for the two plates. Each plate bears on its margin 5-7 (usually 6) spines, of 

 which the first is about as long as the plate, flat, about one-fourth as wide as long, 

 and square-cut at the end ; the second is about two-thirds as long and, although 

 flat, is somewhat more tapering ; the remaining 3-5 spines are very slender, 

 pointed, and about half as long as the first ; the spines are all free, no membrane 

 being developed between them. On the surface of each mouth-plate, at about the 

 centre, is a very conspicuous superoral spine ; it is longer and much stouter than 

 the first mouth-spine, and terminates in a heavy, sharp, triangular point. — Color 

 of alcoholic specimen, purplish pink, lightest on the ambulacra. 



1 specimen from Sagami Bay, Japan; 35° N. x 13S° 48' E., 75 fathoms. 

 Owston collection. 



Pteraster multiporus, sp. nov. 



Rays 5. 11 = 16 mm., r = 10 mm., H = 1.6 r. Breadth of ray at base 11 mm. 

 Interbrachial arcs rather deep and angular. Disc moderately high, vertical 

 diameter 8.5 mm. ; rays not well marked off. Abactinal surface of rays rather 

 high, rounded ; actinal surface flat. Distal end of ray upturned so that ambulacral 

 furrows terminate on abactinal surface. Supradorsal membrane thin, very indis- 

 tinctly reticulated. Spiracula small but exceedingly numerous all over the abac- 

 tinal surface. Paxillae low, with numerous spines (8-10 or more), which are 



