250 ART. 7. 1. IJIMA : HEXACTINELLIDA, IV. 



and every principal seems to be generally two, giving twelve termi- 

 nal points in all to the entire rosette. Quite rarely I have counted 

 as many as fourteen terminal points, in which cases I presume 

 one or two of the principals have had more than two terminals 

 each. The hemihexactinose forms show 7-11 terminal points. 



In one specimen I have noticed the presence in the subdermal 

 space of a number of oxyhexasters, wdiich, besides being normal, 

 had appreciably thinner rays than others in deeper situations. 

 Probably this differentiation of the peripheral oxyhexaster obtains 

 in all individuals of the species, but is not ahvays manifest 

 owing to the sparseness of this kind of oxyhexasters in the 

 periphery. 



The discoctaslers (PI. XVIIL, figs. 6, 12) are of about the 

 same size, and occur in nearly equal abundance, as the oxyhex- 

 asters. Diameter, 180-240,«. Large and small discoctasters occur 

 together promiscuously. The central node is either plain or is 

 supplied with the six hump-like prominences, the latter form 

 being especially common in the case of the smaller of the rosettes. 

 Principals smooth ; about half as long as the terminal tuft ; 5- 

 7h /^ thick in the middle and somewhat thicker towards the 

 outer end. Terminals slightly rough; gradually attenuating; nearly 

 straight or just perceptibly bent after the manner of the latter 

 S. Their number is 6-8, sometimes as few as 4, to a tuft, which 

 expands gently towards the outer end. Terminal discs, minute 

 and pinhead-like ; not dentate. 



31icrodiscohexasters of the usual size and shape, most nearly 

 resembling those of E. mollis (PI. XX., fig. 4) or of E. vngui- 

 culatus (PI. XXI., fig. 9), were found exceedingly sparsely in 



