RHABDOCALYPTUS CAPILLATÜS. 287 



appearance is so vorv characteristic that they constitute a highly 

 important clifferentinl point in the identification of the present 

 species. 



The microdlscohexasters (PL XX IT., fig. 11) are sparsely 

 present. I have met witli them mostly in preparations of the 

 ectosome, but they are not altogether wanting in those of the 

 endosome. Diameter 20-25 /A The figure I have given will 

 suffice to give a good idea of their appearance. 



In the smallest specimen frequently referred to, I have failed 

 to discover a single microdiscohexaster, although the entire body 

 was made into preparations and subjected to examination. 



The basidictyonal plate was found to be represented for the 

 most part by the usual thin and small meshed limiting layer (PI. 

 XXII., fig. 17). Here and there in the sparsely microtubercled 

 beams are seen spicular axial canals in the form of plane crosses. 

 At certain places in the layer the beams are developed, though 

 irregularly, in all the three dimensions ; thus, bringing about in 

 the parts a dictyonal framework of some massiveness. Probably 

 hexactins, and possibly pentactins also, participate in the forma- 

 tion of such parts. I have omitted to determine the disposition 

 of the axial canals contained in those parts. 



Soft Parts. 



Unsatisfactory as is my knowledge concerning tlie histology 

 of the species, I may put down some points from notes taken 

 long ago. I beg to mention here that Plate XXIIL, illustrative 



