ON SOME JAPANESE CALCAREOUS SPONGES. 7 



long and 10 /^ thick. Paired rays nearly equal, curved, gradually 

 tapering and sharply pointed, 70-100,« long and 10/^ thick. 



Subgastral triradiates (textûg. 1, h,i,j). — Sagittal. Basal ray 

 long, straight, gradually tapering, sharp-pointed, about 250 ,« long 

 and 10 // thick. Paired rays nearly equal, widely diverging, lying 

 not in the same plane as the basal ray, shghtly curved, gradually 

 tapering to a point, about 80 /^ long and 12 ,« thick. 



Gastral triradiates (textfig. 1, k, I). — Sagittal. Basal ray much 

 longer than paired rays, quite straight, tapering from base to the 

 sharp point, 140-270,« long and 8-10/^ thick. Paired rays 

 straight, almost equal or slightly differentiated in length, some- 

 what thicker than the basal ray, gradually tapering, sharply 

 pointed, 90-120 /^ long and 10-12 /^- thick. 



Gastral quadriradiates (textfig. 1, m, n). — Almost like gastral 

 triradiates with addition of a short apical ray. Basal ray much 

 longer than paired rays, quite straight, gradually tapering, sharp- 

 pointed, 150-200/^ long and 8-10/^ thick. Paired rays almost 

 straight, subequal in length, slightly thicker than the basal ray, 

 gradually tapering, sharply pointed, 100-120/^ long and 10-12/^ 

 thick. Apical ray much shorter and slender than facial rays, 

 ending sharply, slightly curved and directed upwards, 30-50 /^ long 

 and 8-10 [j- thick. The quadriradiates situated near the osculum 

 have the paired rays curved and more widely diverging than in 

 those of other parts. 



Triradiates of oscular margin (textfig. 1, o, p). — ^Basal ray 

 smooth and straight, gradually tapering, sharp-pointed, slightly 

 longer than paired rays, 100-150 /^ and 10 /^ thick. Paired rays 

 stouter than the basal, widely diverging, almost at right angles to 

 the basal ray, curved, not quite smooth, sharply or bluntly 

 pointed at end, 100-130/^ long and 12/^ thick. 



