MONOGEAPH OF JAPANESE OPHIUEOIDEA. 167 



In both the Amphiodia- and Ainphipholis-grou-p, on the contrary, 

 such an additional papilla is entirely absent, and the infradental 

 one is the highest in position. In the Amphioplus-gvoxrg, all the 

 three groups of oral papillae are well developed and form a 

 continuous row, while in the Amphiura-gï:o\\^, the second group 

 of oral papillœ is entirely, — or mostly, as in certain species of 

 Ainphiura, — absent. In the Amphiodia- and AmphiphoHs-growp, the 

 third group of oral papillae is absent, the two subdivisions being 

 distinguished by the different development of the outermost oral 

 papilla. 



It must be clear from the above exposition, that the Amphiodia- 

 group is not intermediate between the Amphioplus- and Amphiura- 

 group, but the latter are directly interrelated without the intermedia- 

 tion of the first. In my opinion, those species of Amphiiira s. str. 

 with two distal oral papillœ on either side are rather intermediate 

 between Amphiura with a single distal papilla and Amphioplus, 

 instead of being intermediate between the former and Amphiodia. 



My division of the Amphiurinœ into four groups almost coin- 

 cides with Veekill's subdivision of Amphiura s. ext., but not with 

 Kœhlee's. Most species of Kcehlee's Amphiodia (e.g. those in 

 Res. Siboga Exp.), as well as Amphiodia^ digitula Claek, 1911, 

 appear to me not to be genuine Amphiodia, but to be Amphiura 

 having however two distal oral papillae, of which at least the 

 outermost one arises from the adorai shield. 



Key to genera of A^mpJiiurince. 



AmpMophts-gronp :— Oral papiUae +1+11 +111, four or five on either 

 side, forming a continuous row, so that the oral slits are more or 



