120 ART. 1. 1. IJIMA : Hi:XACTINRLLIDA, Hl. 



Äulascus (supposing this to be tenable as a genus distinct from 

 Sympagella), as being the nearest to both, comes in question, 

 since the ci'eation of a new genus for their reception is scarcely to 

 be thought of. The question whether Ca^ycosoma should be 

 amalgamated with either Aulascus or Sympagella, or with both 

 together, seems to be uncalled for at present. 



I completely concur with F. E. Schi lzc (/, c, p. 20 ; vide 

 also my Contrib. I., p. ob) in regarding the onychaster and the 

 oxyhexaster as two hexaster-forms of comparatively trivial differ- 

 ence. At the s^ime time it will be conceded by all that the 

 onychaster is to be considered as a discohexaster with the terminal 

 disc in the most rudimentary state of development, being in fact 

 represented by a whorl of fine claw-like branches. Now in 

 Aulascus {A. johnstoni) the hexasters in question are all disc- 

 ohexasters, in which the terminal whorl of prongs is by no means 

 strongly developed and many of which indeed present a resemblance 

 to typical onychasters (F. E. Sen., '97, p. 527). On the other 

 hand, Calycosoma (as represented by the single species C. validmn) 

 has the corresponding hexaster represented solely by oxyhexasters ; 

 it is of no moment that some of these are in the hexactinose 

 foi'in. Now the new species C gracile shows the same hexaster 

 partly in the form of oxyhexasters and partly in onychaster-like 

 forms ; so that it may be said that in this respect it stands 

 midway between Aulascus and Chlycosoma. It merges into the 

 former through the onychaster-like hexaster and into the latter 

 through the oxyhexaster. Eecourse must then be taken to some 

 other differential indications than the hexaster in order to decide 

 to which of the two genera the new species is more closely allied. 

 So for as tlie spiculation goes, a point that can be utilized as 

 such an index seems to be found in the dermalia and the gastralig. 



