82 ART. 1. — I. IJIMA : HEXACTINELLIDA, III. 



Hyalascus is a genus instituted by me in '96 to receive the 

 single species then known to me, H. sagamiensis Ij. In this 

 species the dermalia are partly pentactins and partly hexactius, 

 the former with the unpaired ray directed proximad and the 

 latter with the distal ray in no way differently characterized 

 from the other rays. In a second species, referable to the same 

 genus which has since become known to me {H. giganteus n. sp.), 

 the dermalia are mostly pentactins with the unpaired ray directed 

 proximad and a distal sixth ray represented by a knob, and 

 occasionally stauractins and simple hexactins. In '96 I was not 

 quite certain as to which family H. sagarniensis should be 

 referred and therefore had to satisfy myself with the remark that 

 it was probably to be considered as a near ally of Ascone7na, 

 without denying at the same time its close affinity to the Ros- 

 sellidœ. I now see, in the nature of the dermalia or in any 

 other respect of the spiculation, nothing that seems to stand in 

 the way of placing the genus under the Kossellids, but much 

 that indicates that it properly should be so placed. 



I think the same may fairly be said of Calycosoma and 

 Calycosaccus. In both, it may be said collectively, the dermalia 

 are either hexactins or pentactins, in the latter case the unpaired 

 ray being outwardly turned, ►^o far the dermalia fall within the 

 range of variability as assigned by me to those of the Rossellidœ 

 {afr. supra). But the one point, which might possibly be consi- 

 dered — as indeed it was considered by F, E. Schulze — to interfere 

 with the introduction of the two genera among the Rossellids, is 

 he fact that the distal ray of the said dermalia shows a spindle- 

 like swelling and exhibits prickles somewhat more strongly 

 developed than those on the other rays, thus causing its resem- 

 blance to a pinular ray. But the resemblance can by no means 



