ON SOME JAPANESE CALCAREOUS SPONGES. 27 



sharp-pointed, nearly as long as basal ray, 160-200 /-« long and 

 16-24;« thick. 



Oxea (textfig. 5, /,/, A). — Very small, slender, straight, broadest 

 nearer one end than the other, tapering towards both pointed ends. 

 One example measured was 130 ;« long and 4 /^ in the thickest 

 part. 



Triradiates of oscular margin (textfig. 5, /, m). — Basal ray 

 quite straight, gradually tapering, sharp-pointed, 130-250 /^ long 

 and 12-16 fi thick. Paired rays stouter and shorter than basal 

 ray, nearly at right angles to the latter ; straight or slightly 

 curved, 120-220 i« long and 16-20// thick. 



Oxea of oscular margin. — There exist two kinds of oxea. 

 The thicker kind is irregularly curved and rather bluntly pointed 

 at ends ; sometimes provided with a nodiform ring at the free 

 end, 250-470^ long and 16-20;" thick (textfig. 5, ?z, o, ;:»). The 

 thinner kind resembles oxea of dermal cortex, but is longer ; 

 broadest near the inner end, 300-460 /^ or more long and 4-6 /^ 

 thick. 



Note. — This interesting species seems to be closely related to 

 Grantessa sycilloides (Schuffnee)^^ of the Indian Ocean, but can be 

 distinguished from it cliiefly by the external appearance, by the 

 presence of thin dermal oxea, by the flagellate chambers being 

 laterally not fused with one another, and by the basal rays of 

 subgastral sagittal trii^adiates being equally developed as in those 

 of subdermal. The species is named after the late Professor 

 MiTSUKUEi, the collector of the type -specimen. 



Locality. — Koajiro Misaki. 



1) Sycortls sycilloides Schuffxee, 1887 (1), p. 420, Taf. XXV, Fig. 10. 



