ART. 12 HEXACTINELLID SPONGES — OKADA 67 



at its upper end, is laterally compressed, and measures 22 mm by 

 15 mm at the middle, and is nearly as long as the body, T5 mm. 

 It is compact looking throughout, being entirely covered by a 

 dense coating of dermal and hypodermal spicules, which seem to 

 have fallen from the Sagami Sea specimens preserved in the Uni- 

 versity of Tokyo. Internally it is traversed by a system of anas- 

 tomosing excurrent canals. The conspicuous features of this sub- 

 species mentioned by Ijima I have found also in these specimens. 

 They show the irregularities of the external surface, which result 

 from a pronounced thickening of the wall into protuberances in 

 the lower part of the body, and occasionally numerous wrinklelike 

 ridges in the general superior surface. But the agreement does 

 not extend into the spiculation, since these specimens lack hexac- 

 tins among the parenchymalia. In the first specimen, the breadth 

 of the paratangential rays of the hypodermal pentactins is usually 

 50/A to QO/x at the base. They occasionally attain a thickness of 140/ut. 

 In most of the oxyhexasters, the ends of the terminals are some- 

 what curved inward at the tip, and I have observed this feature 

 in the preparations from the Sagami Sea specimens. (I have 

 occasionally found the onychasterlike hexaster in the preparations 

 of the latter. I consider the onychasterlike hexaster to be a varia- 

 tion of the oxyhexaster with terminals curved at their ends because I 

 have found a complete series of intergrading forms from one to the 

 other.) 



A thorough examination of slide preparations revealed a single 

 case of a smaller microdiscohexaster, which is nearly like that of 

 the common form of this spicule included in the tissues of other 

 rossellids. The occurrence of this solitary microdiscohexaster in 

 the slide preparations I believe is due to the contamination of the 

 sponges either in the dredge or by other species that may have been 

 placed in the same bottle at the time of collection. I have observed 

 the presence of this spicule with the same size and shape in prepara- 

 tions of C. meyeri from the Sagami Sea. in the tissues of the basal 

 region of the entire stock. 



The second specimen that I refer to this species has essentially 

 the same spiculation but with some points of deviation. Few of 

 the terminals of the oxyhexaster show a curved end. This, however, 

 I consider to be due to individual variation. The hypodermal pen- 

 tactins are fewer in number and distributed sparsely and irregularly 

 on the superior region of the entire stock. But among the dermalia 

 of the stalk region, there are numerous short and robust-rayed 

 spicules irregularly oriented. The paratangentials usually measure 



