234 AKT. 7. T. T.IIMA : HEXACTINELLTDA, IV. 



pointed microtiibercles in much tlie same manner as in Stauro- 

 calyptus pleorhaphides. 



Special gastralia have not been found. 



Oxyhexasters (/. c, PL III., figs. 12 and 13), very abundant, 

 generally normal and rarely hemihexactinose. Diameter, GS-IH/-«. 

 Terminals, two (at most three) to a principal ; nearly straight ; 

 obsoletely rough ; much thinner in the smaller than in the larger 

 oxyhexaster. 



Discoctasters or rather their representatives were found in 

 quite a limited number, — only two cases in all which were dis- 

 covered after a careful search throughout the entire specimen. 

 They are both shown in /. r., PI. III., figs. 10 and 11. The 

 case of fig. 10 is without doubt that of a malformed discoctaster, 

 — at any rate, one in which some of the primary terminals remain 

 free without uniting into secondary principals, though certain 

 others are united into such for a short distance and situated in 

 proper positions on the central node. This central node is nearly 

 cul^ical and shows the rounded bosses corresponding to the primary 

 principals. Diameter, 122 /-«. The other case, shown in /. c., fig. 

 11, may almost be called a discohexaster, in which the primary 

 pi'incipals are in part still distinct and partly fused together. The 

 terminals are all free and radiate in all directions from the ir- 

 regularly shaped central mass, showing as yet no trace of rearrange- 

 ment into the eight bunches of a discoctaster. I regard the 

 s[)icule, though possibly a case of deformity in itself, as representing 

 an early stage in the transformation of a discohexaster into a 

 discoctaster. Speaking on a priori grounds, discoctasters should 

 have passed through a phylogenetic stage appearing much like 

 the spicule now in question. Diameter, S5 p-. 



Microdiscohexasters, quite like those of aS'. sp. a [I. c, fig. 5). 



