JAPANESE ASTEIîOroEA. 251 



lyipsacaster, 



The genus Dlpsacaster was set up by Alcock ['93, p. 87] with 

 the following diagnosis : 



" Disk large, with flat rigid rays of moderate length. Abac- 

 tinal surface of disk and rays with compact definitely arranged 

 paxillce and numerous intervening papulae. 



*' Marginal plates with highly developed ridges and fasciolar 

 channels ; the inferomarginals with enlarged spines. 



" Actinal interradial areas large, with numerous intermediate 

 plates extending far along the rays, and bearing comj^act rosettes 

 of spinelets. 



" Adambulacral plates with a palmate or pectinate furrow- 

 series of spinelets, and actinally with several series of spinelets 

 arranged in rosette-like groups. 



" Madreporiform plate large but concealed. 



" No anus exists, and though a minute pore is present in the 

 centre of the disk, it has no communication with the lumen of 

 the intestine. No pedicellarise." 



There have been described seven species, D. sladeni Alcock 

 [ '92, p. 87], D. identagonalis Alcock ['93a, p. 172], D. eximius Fisher 

 [ : 05, p. 296 ; : 11, p. 86], D. nesioies Fisher [ : 06, p. 1026], D. bore- 

 alls Fisher [ : 10, p. 546 ; : 11, p. 91], D. laetmophilus Fisher [ : 10, 

 p. 546 ; : 11, p. 95], and D. anoplus Fisher [ : 10, p.547 ; : 11, p. 97], 

 the first two from the Indian Ocean and the rest from the Pacific. 



In view of the characters presented by the species described 

 below, it is necessary to modify the original generic diagnosis 

 shghtly by striking out the phrase " the inferomarginals with en- 

 larged spines " and inserting " or more or less soft " between 



