214 I. IJIMA : HEXACTINELLIDA. I. 



meiit of a sixth, proximal ray in the form of a small protu- 

 berance. Paratangential rays 80-II0 11 long and 3-7 /^ thick near 

 the center ; smooth nearly all over. Distal ray somewhat longer, 

 sometimes considerably so ; in the larger gastralia it may be 

 sparingly beset with small prickles near its distal end. 



Of the hexasters, the florlcome measures 75-88 n in diameter. 



The oxyhexaster (PI. VI, figs. "> & (>) is smaller than that of 

 E. marshalU, measuring oO-GO a, sometimes up to 70,", in diameter. 

 It is present in abundance, — decidedly much more so than in 

 either E. imperialis or E. marshallL Compared with the same in 

 either of these species, both the principals and the terminals are 

 somewhat more slender. The principal is 7 /i long (as measured 

 from the center of the axial cross) and 2'/2 p. broad at the 

 middle. It bears usually 3-4, rarely 2 or 5, divergent terminals 

 at the outer end. 



The gmpMocome was recognized to be present in the species 

 for the first time in '95 by F. E. Schulze, although its termi- 

 nals — the rhaphides — were known long before. I find it is 

 common. It may measure 24-5 /^ in diameter, the rhaphides being 

 114 a long, when fully developed. The latter, after they 

 have fallen off from the principals, are still found as usual in the 

 superficial region of the sponge-wall, though not in such great 

 abundance as in E. marshalli nor in such regular arrangement 

 as has been ascribed to their sheaves by Marshall. 



The s'lcve-plate shows the ^''^renchymalia (principalia and 

 comitalia) mainly consisting of thetactins and diactins. The 

 former seem to furnish the principalia more often than do the 

 latter. Occasionally stauractins may occur among the parenchy- 



