248 I. IJIMA : HEXACTINELLTDA. I. 



in variable numbers small groups on the outer surface of chambers 

 (PL VIII, fig. 29). Nuclei like those of the trabeculœ in both 

 size and appearance ; with definitely circumscribed cell-body con- 

 sisting of granular protoplasm. 



Tkcsocytes (PI. VIII, fig. 30 ; th.) found in some numbers 

 scattered on both the outer and inner trabeculse ; 7-1-3// in dia- 

 meter. The contents consist of réfringent, irregular granules or of 

 variously sized spherules. In the same preparation, they are 

 sometimes colored by borax-carmine and sometimes not. In the 

 latter case, they present a yellowish-olive tint ; amongst them 

 the nucleus may be discerned as an indistinct red spot. 



Chambers cup-like or thimble-like ; diameter 45-75 1'- (on an 

 average 57/^). Choanocyte-nuclei small (about l7o/^ in dia.), 

 pale, vesicular, without conspicuous chromatin grains in tlie in- 

 terior ; flattened, when seen in profile ; generally ^-^ /^ apart 

 from one another. Beams of the reticular membrane thin, 

 granular ; meshes distinctly open (!). 



MlSCELLAîs^EOUS NoTES. 



F. E. Schulze (ig', p. 33), when he was describing his 

 R. decora from small fragmentary pieces, was aware of the fact 

 that that species might possibly prove to be identical with my 

 R. olcinoseanaj which was known to him from the preliminary 

 description 1 have given in the Zoologischer Anzeiger in 'g6. 

 If the two species are identical, as I consider them to be, the 

 fault which induced Schulze to create a synonym must be said 

 to have lain chiefly in the brevity of that description of mine. 



Schulze was led to regard the two species as distinct, though 

 very closely resembling each other, from a consideration of the 



