ASTEROIDEA OP NOETH PACIFIC AND ADJACENT WATEB8 FISHER. 



343 



Anatomical notes. — Stomach larjjo and ovnrsiblo, tlio hrpatic rorca IxMiifj lar-^e 

 and oxtendiiif^ to end of ray. Intestinal cuciiin ..f nicdiuni size, saccular, dcprcs-sod, 

 slightlj'subdividod on tho periphery intoafcw irre^rular hroad lobes. Gonads on either 

 side of the interradial septum and openinj; on the side of (he ray close to interradial 

 line. Septa partly calcilied. Anijiulhe double. Tul)e feet without calcareous deposits. 



Type.— Cat. No. 22342, U.S.N.M. 



Type-locality.— Albatross station 4410, between Santa Catalina and Santa 

 Barbara Islands, California, ITS to 10.5 fathoms, fine <;ray sand and rocka. 



Distribution. — Southern Berinj; Sea and off southern California, in 57 to 313 

 fathoms. 



Specimens examined. — Forty-sLx, from the following; stations: 

 Spedmem of PeriboUuUr biterialit eaamined. 



Depth. 



Nature of bottom. 



CoUecUon. 



2927.. 

 3317.. 

 4399.. 



4788.. 

 4790.. 

 4791.. 

 4792.. 



00 San Diego, California 



North of I'naloska 



Between San Diego and San Clem- 



ente Island. 

 Between Santa Calalina and Santa 



Barbara Islands. 

 Between Santa Barbara and San 



Nicholas Islands. 



Off Medni, Commander Islands 



Off Bering Island 



313 



165 



264-285 



178-195 



291-298 



green mud 



coarse sand, gravel, rocks., 

 fine gray sand 



gray sand, gravel., 

 gray mud, rm-ks... 



green sand. 



pebbles 



rocky 



pebbles 



C.S.Ntt.Uas. 



Do. 

 .^fhUroft. 1904. 



Do. 



Do. 



iiittUron, 1906. 



Remarks. — One other species of tliis genus is known, P./oRiculatus Sladen. from 

 45 fathoms off Chile (46° 53' S. ; 75° 12' W.). The more striking differences between 

 the two forms are the arrangement of the tube feet in two series in biserialis (four 

 in foUiculatus) , its more open abactinal skeleton, fewer plates, longer paxillar 

 spinules, and less numerous actinal spines (four instead of six in each transverse 

 row). A ])rominent furrow spinelet is present in biseriaUs, the mouth plates have 

 four marginal and no suboral sjiines, the inferomaiginal plates may be ejisiiy 

 distinguished from the adambulacral if dried, and the madreporic body, though 

 variable in size is relatively smaller than in foUiculatus. Judging by Sladen's figure 

 the rays oi foUiculatus are longer and the fascicules of spineiets much more numerous 

 and com]iactly jilaced than in biseriaUs. 



In tlie arrangement of tube feet, hiserialis is not precisely ty])ical of the genus, 

 but in other characters the two known species are essentially similar. 



Family PTERASTERID.Ti: Perrier, 1875. 



Spinulosa with cruciform or lobed plates bearing paxilliform grou]>8 of spineiets 

 which support a supradoi-jial canopy or membrane distinct from the abactinal wall; 

 between the two a nidamental cavity is formed, opening centrally by a valved 

 apeiliire, the osculum ; actinolateral s]>ines (arising from adambulacral plates) jire- 

 sent supporting an actinal wt>b, or merged in actinal lloor; external to adambulacral 

 plates, a series of segmental apertures all along ray, o]>ening into nidanuMital cavity 

 and guarded by a specialized opercular s|)iiielet or ]>apilla; no actinal intennediate 

 plates; mouth plates broad and plowshare-shaped; meinbrauous interradial septa. 



