184 ART. 7. — T. TJIMA : HEXACTINELLIDA, IV. 



pentactins, either isolated or in loose tufts, arise from the top of 

 small papilla-like prominences of the dermal surface, situated at 

 intervals of 1-2? mm. The pentactins, wherever they have escaped 

 the influence of abrasion, are so numerous and crowded together 

 that they form a gauzy layer of 3 or 4 mm. thickness over the 

 dermal surface. 



The latter is tolerably smooth except for the above-mentioned 

 papillae. Close beneath the thin ectosomal layer are seen the 

 roundish apertures of tlie incurrent canals, which, in the lower 

 part of tlie sponge, may measure up to Ih mm. in diameter. The 

 smallness of the canals in comparison with those of the first 

 specimen seems to be sufficiently accounted for by the much 

 smaller size of the individual. 



The characters of the gastral surface are essentially the same 

 as in the first specimen. Namely, while most excurrent canalar 

 apertures are freely open, certain others are covered over liy an 

 ii-regularly meshed endosomal latticework. A number of small 

 oxydiactinic parenchymalia are seen to project their fine ends 

 beyond the gastral surface to the extent of about 1 mm. or more. 



Taken all in all, the general appearance of the species is 

 closely similar to that of both ä dowli7igi and S. tubulosus, but 

 especially of the latter. With our present knowledge it would 

 be unsafe to pick out this or that macroscopic character in the 

 above description of the specimens as in any degree distinguish- 

 ing the species from either of the two just mentioned. It may 

 further be stated that the spiculation, so far as the kinds of 

 spicules entering into it are concerned, is to a great extent, if 

 not essentially, the same in all the three species (to which I may 

 add S. entacantliKS n. sp. as a fourth). Nevertheless, there exist 



