JAPANESE ASTEEOIDEA. 329 



" Remaries. — This species is distinct from any other Pentagonaster with 

 wliich I am acquainted, and is readily distinguished from all the Pacific 

 forms at present known. Its general character points to some alliance with 

 Pentagonaster inter médius, of which Pentagonaster arcuatus is perhaps the 

 the Pacific representative. In some of the structural details Pentagonaster 

 aî'cuatus resembles forms grouped in the genus Nymphaster, of which I was 

 at first disposed to consider it an aberrant species. I am still in some 

 doubt as to whether this form is correctly referred to the genus Pentagonas- 

 ter, but with only a single example for study, that course appeared to me 

 the most justifiable." 



Alcock mentions this species from the Indian seas, and makes the 

 following remarks [ '93, p. 89] : 



" Pentagonaster arcuatus Sladen. 



" I am not quite certain about this determination, although oui- species 



conforms exactly to Mr. Sladen's description, and although the habitat 



' supports it- — the ' Challenger ' specimen being dredged in the green mud of 



the Japanese Sea at 345 fathoms, and our specimen being dredged in the 



green mud of the Andaman Sea at 271 fathoms." 



Vereill refers this species to Medlaster, and there is no doubt that it 

 presents certain resemblances to 3ïediasler œqualis Stimpsox, the type 

 species of the genus, a specimen of which the writer owes to the kindness 

 of Dr. W. K. Fisher. Verrill adds the following remarks, evidently based 

 on Sladen's description [Yerrill, '99, p. 183] : 



" This species has a few small pedicellariœ on the abactinal plates, 

 similar in size to the granules. 



" South of Yeddo, Japan, 345 fathoms." 



Kœhler [ : 09a, p. 70] makes some remarks on this species in connec- 

 tion with liis P. cuenoti, which is no doubt very closely related to it. He 

 says : " M. Alcock a signalé un P. arcuatus provenant des îles Andaman, par 

 271 brasses de profondeur. Je n'ai pas vu ce Pentagonaster, mais celui que 

 je viens de décrire n'est certainement pas un P. arcuatus. Sa forme rapelle 

 bien celle de cette dernière espèce, mais il en diffère par les plaques mar- 

 ginales dorsales et ventrales en grande partie nues, par les plaques dorsales 



