186 



BUI.LETIN 76, UNITED STATES NATIONAL MUSEUM. 



The infcromiirginal armature consists of slighth- spaced subpapilliform slightly- 

 flattened spinelets with a transverse series of enlarged lanceolate appressed spinules. 



Adambulacral plates with five or sLx tapering furrow spinelets compressed as 

 in jmrelii but longer and more delicate, as are those of actinal surface. The figure 

 •will show the dilTerences better. 



The aroiature of the mouth plates is composed of terete or slightly compressed, 

 tapering, rather slender spinelets, much longer than in farelii. The arrangement 

 of spinules, however, is not materially different. 



Spinelets of actinal intermediate plates ar(> spaced and of a swollen papiUiform 

 shape. A number of plates bear an enlarged spinule, but these are usually scarce. 

 Compared with a Japanese specimen of j>arelii, the spinelets are longer and less 

 o-ranuliform, and ilecidedly more spaced; the difference is not so obvious, however, 

 when Alaskan specimens are used for comparison. Postadambulacral pectinate 

 pedicellariffi present; but sometimes scarcely more than simple fascioles. 



r;//)f.— C'at. No. 22.334, U.S.N.M. 



Type-locality. — Albatross station 4236, near Yes Bay, Behm Canal, Alaska, in 

 147 to 205 fathoms, rocks, coarse sand. 



Distribution. — Oregon to Queen Charlotte Sound and north, intergrading with 

 Ps. parelii in the region of Kadiak Island. 



Specimens examined.. — Nine from the following localities: 



Specimens of Psevdarchaster parelii alascensis examined. 



a Not typical. , 



Remarks. — Since describing this form in 1905 I have seen considerable material 

 not then accessible, including specimens of Ps. parelii from the Atlantic and the 

 Sea of Japan. The special characters of the present race are exhibited only by 

 specimens from off British Columbia and southern Alaska, but examples from 

 Kadiak and vicinity are intermediate, though a little nearer to parelii. It is 

 impossible to assign tlicni satisfactorily to either form. 



That Ps. pusillus, from Cahfornia, is not a dwarfed variety of this race, or of 

 parelii, becomes very evident when equal-sized specimens are compared. A small 

 specimen (R = 37 mm.) from station 4201 is nearer typical parelii than the adults; 

 the paxillar and marginal granulation is more compact, and the adambulacral 

 spinelets shorter. Compared with pusiUus, this specimen has longer ami narrower 

 rays, very wide superomarghial plates^^ more crowded paxillaj (in view of their 

 variation in pusillus the size is of no importance), much narrower paxillar area, 



