268 I. IJIMA : HEXACTINELLIDA. I. 



rays in R. komeyaiiud, bundles of spicules, similar to the parenchy- 

 mal strands. Their free ends bear unmistakable signs of having 

 been forcibly broken off. Whether a central nodal plate, such 

 as is possessed by Didyaulus elvjavs (Schulze '95), originally 

 existed but had been torn away, can not be ascertained ; but I 

 think this much may be said, tliat the principal beams are in 

 the main radially disposed and that the meshes are comparatively 

 wide with angular corners. How far the radial arrangement of 

 the main beams, consequent upon the strong coronal ray enter- 

 ing into their support, can be verilied in typical specimens of 

 R. phoenix from the Atlantic remains to be seen. 



Parietal oscula (see PI. XI, fig. 2), circular in shape and 

 mostly measuring 3-5 mm. in diameter, perforate the wall at 

 intervals of .3-10 mm, arranged in two intersecting systems of 

 irregular, oblique rows. They are thin-edged as usual and 

 occupy each the center of a flatly depressed area bounded by 

 the main strands of the parenchymal skeleton. 



Both the incumnit and tlie excurrcnt canals arc visible on 

 their respective sides of the wall as small and shallow depres- 

 sions under 1 mm. in diameter. 



The dermal surface had been much abraded, exposing the 

 more superficial parenchymal bundles. However, the occurrence 

 of well- developed ledges or of hillocks with prominent prostalia 

 must evidently be entirely denied. The surface is on the whole 

 even, or more properly, gently undulating on account of the low 

 and broad swellings between the parietal oscula. 



The dermal laj'er was found preserved in patches. In such 

 places I have found the surface studded at intervals of 2-3 mm. 



