290 I. IJIMA : HEXACTINELLIDA. I. 



('g8, p. 433) that the gastralia are sword-shaped hexactins like 

 tlie dermalia is not corroborated hy the facts. 



The hcxnsters of the species are the spherical discohexaster, 

 the oiiychaster and the graphiocome. Remarkable is the absence 

 of floricomes, which should be present in W. flemmingl in addition 

 to all the three kinds of hexasters ahovc-mentioned. 



The spherical discohexaster (PI. XIII, figs. 12-14), which 

 is of great beauty aud closely resembles the same of W. flcmmingi 

 in appearance, is found in great abundance, especially in the 

 periphery inside the dermal paratangentials. Frequently it is 

 found also outside these and sometimes even borne on the tip of 

 dermal hilt-rays after the manner of floricomes in other Euplec- 

 tellids. In deep parts of the sponge the discohexaster is wanting, 

 or at any rate quite scarce. 



In diameter the discohexaster measures 75-90 n. Each short 

 and rather slender principal bears at the outer end a plano- 

 convex or nearly hemispherical disc (fig. 13). From all over 

 the outer arclied surface of this disc spring out numerous termi- 

 nals, which are slender at base but gradually thicken outwards, 

 finally to end with a watch-glass-like or hemispherical, marginally 

 minutely serrated, terminal disc of about 4/^ diameter (fig. 14). 

 It is difficult to determine the number of the terminals. In well 

 developed cases, there must be to each principal thirty or more 

 of them in a diverging bunch. In each bunch the more peri- 

 pherally situated terminals are gently curved at base, while the 

 central ones are straight. All the terminals diverge outwards in 

 such a way that the terminal discs are uniformly distributed over 

 the entire surface of the exquisitely spherical hexaster. 



