36 AKT. T. 1. IJIMA : HEXACTINELLIDA, IV. 



opeclj each short principal bearing 2-4 terminals. Only occasion- 

 ally do hemihexactinose forms occur, especially in the middle of 

 the choanosome. The terminals are only moderately strong ; 

 their surface is rough. The minute processes causing this rough- 

 ness, when examined under a strong i)0\ver of the microscope, 

 are seen to l)e distinctly inwardly directed (lig. lo). 



The discohexasiers (PI. VI., figs. 15 and IG), present like- 

 wise everywhere in the choanosome, are less abundant than the 

 above, though in several parts of the subdermal and subgastral 

 regions they are found lying numerously together side by side. 

 They are mostly of al)0ut the same size as the oxyhexasters or 

 of a larger size, reaching up to 100 //. in diameter. Others are 

 so small as to measure only 35 /y. in diameter ; discohexasters of 

 such small size may be taken as representing the microdiscohex- 

 aster of the species. However, it is important to mention that 

 the larger discohexaster (fig. 16) and the microdiscohexaster (fig. 

 15) in the present species are much the same in general a2:>pear- 

 ance and are besides gradationally linked together l)y intermedi- 

 ate sizes. So tbat, it is also not improper to say that discohex- 

 asters are present in only one form, which is quite variable as 

 to size (35-100 //. dia.), the smallest being less than half the size 

 of the largest as measured by the diameter. Much the same 

 relation seems to ol)tain among the corresponding rosettes (25- 

 100 // dia.) of Scyphidiniib sp. { = Rossella sp. F. E. Sen. '99, \). 

 43) described by F. E. Schulze from the coast of Chile ; where- 

 as, in S. septeiitrionale and S. longispina the microdiscohexaster 

 is clearly distinguished from the larger discohexaster-form not 

 only l)y its smaller size but also by having the terminals in far 

 greater abundance. — In the present species it may be said in 



