ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER 67 



the largest being 0.34 to 0.39 mm. long. But the main difference is in the struc- 

 ture and in the presence of more numerous teeth (four or five, less often six) in 

 the vertical series of each jaw. Compare figures. The presence of numerous small 

 oral straight pedicellariae (pi. 16, fig. 5) is a feature not found in magister, except 

 sporadically in rather small specimens (station 3500) when only one or two are 

 present. 



Madreporic body very small, situated variably in the outer half of r. 



The gonads, similar to those of magister, open just under the inferomarginals a 

 little less than the length of r from the interbrachium. 



Type.— Cut. No. E. 1420, U.S.N.M. 



Type-locality.— Station 4867, off east coast of Korea, 36° 31' N., 129° 46' E.; 

 150 fathoms, green mud, fine gray sand; bottom temperature 33.4 F.; five specimens. 



Distribution. — This race is probably found throughout the cold western part of 

 the Sea of Japan. 



Remarks. — This form is well marked on account of pedicellarian characters 

 alone. The slighter development of the actinal areas may prove to be a fundamental 

 difference. The skeleton, if anything, is closer knit than in magister. The lobes of 

 the abactinal plates are broader and the spinelets have rather more numerous termi- 

 nal points. 



Genus PERANASTER Fisher 



Peranaster Fisher, Ann. and Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 252. Type Pedi- 

 cellaster chirophorus Fisher (Celebes). 



Diagnosis. — Pedicellasterinae resembling PediceUaster but differing in having 

 spatulate unguiculate straight pedicellariae; only one sort of crossed pedicellariae; 

 the gonads opening dorsally, and the actinal plates in normal longiseries (not reaching 

 and of ray). Carinals, marginals, and actinals + form, monacanthid, in regular longi- 

 series; dorsolaterals Y form in a zigzag longiseries; papular areas in two dorsolateral, 

 one intermarginal, and two actinal series for each side; adambulacrals triplacanthid 

 and diplacanthid (the spinelets longer than the marginals); oral plates relatively 

 large with a longitudinal series of four or five spinelets; postoral pair of adambulacral 

 plates separated interradially ; tube-feet biserial; gonads opening dorsally. 



Remarks. — This group resembles Anteliaster in having the actinal plates arranged 

 in longiseries, and in the form of the straight pedicellariae; but differs in having the 

 gonads opening dorsally at the margin of the abactinal area, and in the different 

 form of the crossed pedicellariae. These have an enlarged tooth on one side of the 

 expanded terminal portion of the jaw. They resemble some of the pedicellariae 

 intermediate between the two types characteristic of PediceUaster, s. s. 



Hydrasterias has no actinal plates on the ray and the crossed pedicellariae are 

 more nearly like those of Anteliaster. 



The genus is known only from the type, taken at station 5656, Gulf of Boni, 

 Celebes, 484 fathoms. 



