196 ART. 2. — H. MATSUMOTO : 



g — Disk rather thick, distinctly squamated above ; radial shields short ; 



lower arm spines spur-shaped and rough at the tip euopla. 



gg — Disk very thin, mostly naked, the scales persisting only around the 

 radial shields, which are long and rather narrow ; arm spines 



conical, not rough acryskda. 



aa — Single tentacle scale to each pore. 



Ji — Three arm spines. 



'/ — Disk distinctly squamated both above and below. 



,/ — Disk scales rather fine ; radial shields very wide, widest near the 

 inner end ; oral shields rounded, longer than wide ; adorai shields 

 Avidely separated from each other in the interradial line ; dorsal 

 arm plates separated from one another by the lateral arm plates ; 

 ventral arm plates pentagonal, longer than wide, only slightly in 

 contact with one another ; arm spines subequal acacia. 



jj — Disk scales coarse ; radial shields not very wide, wider outwards 

 oral shields oval, much wider than long ; adorai shields widely 

 meeting with each other in the interradial line ; dorsal arm plates 

 widely in contact with one another; ventral arm plates hexagonal 

 or heptagonal, widely in contact with one another ; middle arm 

 spine longer than the other two pycnodoma. 



a — Interbrachial ventral surfaces naked ; radial shields long and 

 narrow ; oral shields rounded pentagonal, wider than long ; adorai 

 shields not meeting with each other in the interradial line ; distal 

 oral ]3apilla long and spiniform ; dorsal, as well as ventral, arm 

 plates slightly in contact with one another ; arm spines subequal . . 



carcliara. 



hh — Four to seven arm spines. 



k — Four or five arm spines, of which the lowest is the longest and 



the third from below the shortest. 

 I — Four, rarely five, conical arm spines, of which the maximum length 

 does not exceed twice the corresponding arm joint ; disk scales ill- 

 defined, not distinctly imbricated, but pavement-like ; radial shields 

 very long and narrow, bar-like ; oral shields large, much wider than 



