166 ART. 2. — H. MATSUMOTO : 



to be less adapted to the purpose of bringing out the interrelation- 

 ships of the different subdivisions of this subfamily, which is very- 

 extensive and very rich in species and species groups. Therefore, 

 I am obliged to adopt the second way. 



We may also ask if Veeeill's subdivisions of Amphiura 

 s. ext. are sharply distinguishable from one another or not. My 

 answer is affirmative. Unfortunately, Amphiura s. str. and 

 Amphiodia, or Amphiodia and Amphioplus are frequently confused 

 by certain authors. My method of distinguishing them from each 

 other is as follows. 



I distinguish three groups of oral papillae in the present 

 subfamily : the first group is infi-adental, arising from the dental 

 plato^-*; the second arises from the oral plate ; the third arises from 

 the adorai shield. When a papilla arises partly from the oral 

 plate and partly from the adorai shield, it is referred to the 

 second group. Now, let +1 denote the presence of the first 

 group, —I its absence, +11 the presence of the second group, &c. 

 Then, the oral papilla3 of Veeeill's subdivisions of Amphiura s. 

 ext. may be shown by formulae as follows. 



Amphioplus- gvow^ : + 1 + II + III. 



Amjjhiodia-gro'op : + 1 + II — III. 



Amphipholis- gvoM\) : +1 +11 — III."^ 



Amjyhiur a- group : +1 — 11 + III, or rarely +1 +11 +III. 



In both the Amphioplas- and Amiyhiura-group, there is present 



an additional papilla just outside and above the infi*adental one, 



so that the latter is not the highest in position of all the papillae. 



1) The infradental papillic arise from the oral plates, notwithstanding its intimate relation 

 to the dental plate in the adult (H. L. Cjlaek : Growth-changes in Brittle Stars; Publication No. 

 182 of the Carnegie Inst., Washington, 1914.). 



2) The outermost oral papilla of the AmjMpholis-gioup arises from the adorai shield, not- 

 withstanding its partial relation to thel ora plate in the adult (Ci.aek : loc. cit.). 



