ASTEBOIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHEB. 

 Specimens examined. — Eleven, from the following localities: 

 Specimens of DiplopterasUr muUipes examitied. 



373 



LocaUty. 



Depth. 



Nature of bottom. 



black sand, Kinvol 



mud, sand, shells 



mud 



ftnc gray sand, gravel. 



green mud, sand 



gray mud 



green mud 



coarse pebbles 



o Bottle broken by earthquake, 1906; some doubt as to label; probably this station. 



Remarks. — The differences between this species and the two others of the genus 



are noted in the foregoing key. 



The c.\plorati<)ns of the Albatross in the North Pacific have more than doubled 

 the known range of this s[)ecics, which was heretofore recorded onh' from the North 

 Atlantic. Some of the Bering Sea examples are very large (R=over 90 mm.), 

 and therefore show a tendency shared by other North Atlantic forms found in this 

 general region; as, for example, Ilcnricia sanguinolfnia, I'lrrastfr inilitaris, Pseud- 

 archaster parelii. These specimens, if not the largest known Ptcni-iti-iiiUv. are at 

 any rate the fleshiest and heaviest. 



Genus HYMENASTER \A'yville Thomson. 



Hymtnastcr Wvville Thomson, The Depthn of the Sea, 1K7:1, p. 12(\. Type, //. pfllunriut 



Wyville Thomison. 

 Diagnosis.— PtcT&&tem]ai in which the armature <>{ the adambulacral plates 

 does not form transverse webbed combs, the spinclets being independent : nida- 

 mental cavity spacious; spinelets of pa.xillie not protruding through, but support- 

 ing the membrane, which contains numerous muscle fibers and few to many spiracula. 



KEY TO THE SPECIES OT HTMENASTER HEREIN nEHCRIBED. 



n'. .\dambula(ral armature consisting of one spinelet; Bize very large; paxillic forming vpeeial raiw>d 



ttrean; spiracula small in definite circuins<'rihed aroaw kahUri, p. 373. 



a'. Adambulacral armature consisting of more than one spinclel; spiracula not in definite rircum- 

 Bcribed areas. 

 6'. Median radial paxillie very much reduced in size; with one to three batnal lobce; five rows of paxil- 



1h> on ray; adambulacral spinelelj<, two or three peritionolwi, p. 376. 



6'. Median radial paxillie not greatly re<luced in size, with four bami lobe*; nine rows of paxillip 

 along ray; very numerous small spiracula; adambulacral spinelets, four or five. 



quadrupinmut. p. 380. 

 HYMENASTER KtEHLERI FUtaer. 



ri. WS. lis. 1; pi 117, lip. -1 

 Hymetuuter hrhteri FiBHEK, Ann. and Mag. Nat. nisi., ser. 8, vol. .S, Feb., 1910, p. 170. 

 Diagnosis. — Very near to //. nobilis Wv-villc Thomson," which it resembles in 

 general appearance, number, and arrangement of paxillar spines ami adambulacral 



"For figures and deivription, Sladen IW9, p IW, pi. 87, fig*. 1-3. 



