MONOGKATH OF JAPANESE OPHIUROIDEA. 175 



Amphichilus, g. nor. 



Disk covered with fine, imbricating scales. Radial shields 

 small, narrow, usually joined in pairs. One apical and two distal 

 pairs of oral papillie to each oral angle ; the apical pair are 

 infradental, arising from the dental plate ; the inner pair of the 

 distal ones arise from the oral plate ; the outermost pair are very- 

 large, wide, operculiform, arising ù^om the adorai shield. Besides, 

 an additional papilla occurs just above and between the apical 

 and inner distal papillae, so that the oral shts are perfectly closed. 

 Arms long, slender, flattened, inserted ventrally to the disk, only 

 horizontally flexible. Three arm spines. One or two tentacle 

 scales to each pore. 



This new genus includes Amphiura dalea Lyman, 1874, and A. 

 intermedia Kœhlee, 1905, besides the genotype, Amphichilus 

 trichoides, nov. 



Amphichilus differs from Amphioplus in the presence of only 

 three genuine oral papillse, besides an additional one, on either 

 side of each oral angle ; in the very large and operculiform outer- 

 most oral papilla ; and in the usually joined radial shields. It 

 differs fi-om Amphlpholis in the discontinuous arrangement of the 

 genuine oral papillae, and in the presence of the additional oral 

 papilla, which fills up the space between the apical and inner 

 distal papillae. 



Ainphichilus trichoides , sp. nov. 



One specimen ; locality unknown, perhaps Sagami Sea. 

 Diameter of disk 6 mm. Length of arms CO mm. Width of 

 arms at base 0.5 mm. 



Disk circular, rather convex dorsally, covered with very fine. 



