CLARK: JAPANESE AND EAST INDIAN ECHINODERMS. 285 



much longer than the stalk that bears them ; these spines arc slender and approx- 

 imately equal, so that the entire abactinal surface is relatively smooth. Aside 

 from the tips of these spines there do not appear to be any calcareous particles in 

 supradorsal membrane. Osculum rather small, surrounded by 30-40 rather short, 

 closely webbed spines. Ambulacra rather narrow ; feet in two rows. Adambu- 

 lacral plates each with five (sometimes six) 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, 

 little longer than outermost adambulacral spine, flattened and widened at the 

 bluntly-rounded tip ; they are subequal and the actino-lateral " fringe " is accord- 

 ingly narrow and nearly parallel-sided. Aperture-papilla small, free only along 

 aboral edge. Mouth-plates moderate, each with six slender, nearly cylindrical 

 but pointed spines along the margin, the innermost largest, outermost smallest; 

 the entire group of twelve spines is completely united by a thin but conspicuous 

 membrane ; superoral spines moderately stout, cylindrical but pointed, slightly 

 exceeding the longest oral spines. — Color of alcoholic specimen, purplish pink. 



1 specimen from Sagami Bay, Japan; 35° N. x 138° 48' E., 75 fathoms. 

 Owston collection. Although taken at the same station with obesus, it is an en- 

 tirely distinct species. It is closely allied to reticulatus from the Hawaiian 

 Islands, but differs in having webbed oral spines, short, broad, actino-lateral 

 spines, and low paxillae. 



List of the species of Pteraster. 



militaris 0. F. Miiller, 1776. Zool. Dan. Prod., p. 234. North Atlantic and 



Arctic Oceans, 10-618 fathoms, 

 pulvillus M. Sars, 1861. Overs. Norg. Ech., p. 62. North Atlantic and Arctic 



Oceans, 20-80 fathoms. 

 danae Yerrill, 1869. Proc. Bost. Soc Nat. Hist., 12, p. 386. Atlantic Ocean 



off east coast of South America, 30(?)-55 fathoms, 

 affinis Smith, 1876. Ann. Mag. Nat. Hist., (4) 17, p. 108. Royal Sound, Ker- 



guelen Island, 5-28 fathoms, 

 caribbaeus Perrier, 1883. Stell. du "Blake," p. 216. Subtropical western At- 

 lantic Ocean, 151-422 fathoms, 

 aporus Ludwig, 1886. Zool. Jahrb., 1, p. 293. Behring Sea. 

 rugatus Sladen, 1889. Challenger Report, 30, p. 473. Antarctic Ocean, vicinity 



of Heard Island, 150 fathoms, 

 semireticulatus Sladen, 1889. Challenger Report, 30, p. 475. Antarctic Ocean, 



near Marion Island, 69 fathoms, 

 stellifer Sladen, 1889. Challenger Report, 30, p. 474. Antarctic Ocean, near 



Cape Horn, 245 fathoms. 



