JAPANESE ASTEROIDEA. 405 



more conspicuous than in others, and all are more conspicuous adjacent to 

 adambulacrals where they are often roofed by pectinate pedicellariee. j\Iany 

 of the plates bear a central enlarged pointed spinule directed toward margin. 

 The nmnber of plates bearing such spinules is variable. 



" Madrepoiic body small, situated one-third distance from centre to 

 margin ; striations very irregular, the ridges between strise coarse. 



"^w«/owic«? Jiofos.—Superambulacral plates present, extending along ray 

 as far as do the intermediate plates, and absent from first ambulacral 

 ossicle ; they are rather small. Gonads in a single tuft on either side of 

 interradial septum, which is membranous. Anus present. Intestinal cœcum 

 large with ten or eleven radiating, slightly branched divisions. Tube feet 

 with well-developed sucking disks ; no deposits. 



" Variations. — The principal variations have been noticed in the above 

 description. To recapitulate, they concern chiefly the following characters. 

 Rays, Avhicli vary in breadth and length, being a little shorter in Japanese 

 specimens, but also vary in Alaskan examples. Paxillse : more compact in 

 some individuals, with a sHght différence in width of paxillar area on rays, 

 due to the variable width of superomarginals. Superomarginals : variable 

 in width and number, being apparently slightly broader in Japanese speci- 

 mens (but occasional examples, stations 3225 and 3258, from Alaska, also 

 with broad plates) ; in number varying from thirty-three (Japanese) to fortj^- 

 tlnee (station 3258) in examples of same size (R, 70 mm.), the Japanese 

 specimens consequently having longer plates. Inferomarginals : variable in 

 width as superomarginals ; covering either very compact and polygonal or 

 more open and squamiform. Variations in adambulacral armatm-e, mouth 

 plates and actinal intermediate plates, sufficiently treated above. 



" Young. — The t}-pe described by vSladen is a small specimen. The 

 smallest in the collection from station 4792 has the following dimensions : 

 R, 19 mm. ; r, 8 mm. Superomarginals, twenty. The actinal inteiTadial 

 areas are small and lack enlarged spinules, as do the adambulacral plates 

 on the proximal liaK of R. Teiminal plate large, subglobose ; proximal 

 superomarginals with small bare spot ; spimues of inferomarginals only a 

 trifle enlarged beyond gi-anules. 



