IMONOGKxM'H or JAPANESE OrHIUIlOlDEA, 333 



Opliioplax lamellosa is quite near to both 0. Ijungmani Lymak, 

 1875, and custos (Kœhlee, 1896), as well as to Ophiopeza reduda^^ 

 Kœhlee, 1907. It is distinguished from 0. Ijungmani by the 

 presence of the primary plates, by the coarser disk scales, by the 

 shape of the radial shields, by the disk margin being not so 

 closely granulated, and by the shape of the oral shields ; from 0. 

 custos by the presence of tlie primary plates, by the coarser disk 

 scales, by the shape of the radial shields, by the adorai shields 

 not meeting within, by the shape of the first and second ventral 

 arm plates, by the presence of the lamellar plates at the arm 

 bases, and by the shape of the dorsal arm plates ; and from 0. 

 reducta by the dorsal surface of the disk being free of granules, 

 by the radial shields not being divergent, and by the shape of 

 the ventral arm plates. Kœhler states that, in his specimens of 

 0. custos the dorsal surface of the disk was also closely covered 

 with fine granules during life, but that they subsequently dropped 

 oif. Whether the same holds true for 0. lamellosa can not be 

 ascertained, as I have not been able to examine living specimens. 



Key to genera of OpJnonerekUnœ, 



A — Accessory dorsal arm plates absent ; a row of spines present along 



the brachial borders of the disk, jnsfc above the arm bases 



OpJiiodoris. 



^^— Accessory dorsal arm plates present. 



a — Only two large accessory plates to each dorsal arm plate 



OpJiionereis. 



1)' Opldopeza reducta, which Ci.Ar.ft refers to his genus Bathyjjcctinura, appears to Die to be 

 merely an Ophioplax. The presence of only three long, cylindrical arm spines, and of only five 

 papilLo, the annulation on the arms, and the naked oral plates, are all characters of Ophioplax, 

 and not of the genuine Bothilpectinvra. 



