E. KOMEYAMAI. SPICÜLAT10N. 259 



and sparsely niicrotubercled ; extreme end rounded, sometimes 

 conically pointed. 



Parenchymal hexactms of small or medium size occur only 

 sparingly in the bundles of the wall proper. It required a 

 study on sections in order to verify this fact. They occur more 

 commonly in the cuff as well as in the parietal prominences 

 (PI. X, fig. 11), in which parts they lie with one axis directed 

 radially and in association with the proximal radial ray of the 

 prostal hexactins soon to be described, into which they seem to 

 merge by a gradational series of intermediate forms. — The paren- 

 chymal hexactins are generally under 1 mm. in axial length. 

 Not infrequently the radially directed axis in those situated in 

 the cuff or in the parietal prominences is much longer than the 

 others. Thickness of rays about 10 !>■ or less ; end generally 

 bluntly pointed and sparsely prickled. 



The coronal spicule (PI. X, fig. 8) is evidently to be considered 

 as a specially developed element of the parenchymalia. I may 

 call it an oxypentactin with unequal rays, the sixth ray being 

 represented by a mere boss. Its shape, position and manner of 

 arrangement are essentially the same as in the corresponding 

 spicule of R. phœnix (PL XÏ, figs, o, G). The same spicules in 

 similar arrangement are also know^n from Dictyaulus elegans 

 (Schulze '95). 



With respect to its longest complete axis the coronal oxy- 

 pentactin is disposed longitudinally. That axis is more or less 

 curved, the concavity facing inwards. The atrophied sixth ray 

 is situated on the concave side. 



The superiorly directed ray of the longitudinal axis is the 

 free coronal ray, the most strongly developed of all. In a large 



