182 AßT. 7. — I. IJIMA : HEXACTIXELLIÛA, IV. 



The external clioanosomal surface (PL XIII., fig. 1) is 

 tolerably even and presents a coarsely fibrous appearance. It 

 exhibits variously sized, roundish, incurrent canalar apertures, tlie 

 laro-est of which mav measure 02 mm. in diameter. The larger 

 apertures are separated from one another by an interspace nearly 

 as wide as themselves or even considerably wider. They lead into 

 deep pit-like canals. 



The gastral surlace (PI. XIII. , fig. 2) is on the whole ex- 

 cellently preserved. On it there open luunerous, closely set, 

 roundish and sharp-edged excurrent apertures measuring not more 

 than 2 mm. in diameter. Most of them open freely and directly 

 into the gastral cavity without a covering endosome, similarly as 

 in several species of the genus (aS'. rœperi, dowlingi, tubulosus, 

 solidus). In many cases the apertures are provided with an iris- 

 like rim. It is, however, a remarkable fact that a covering endo- 

 somal latticework is not entirely undeveloped. Such a structure 

 is iu fact to be fouiid here and there in small irregular areas, 

 some of which are to be seen iti PI. XIII., fig. 2. It consists 

 of irregularly reticulate beams, mainly composed of diactinic hypo- 

 gastralia and inclosing small angulate meshes. These meshes are 

 open, not filled in by a continuous gastral lacework ; they can easily 

 be distinguished from the underlying canalar a};ertures proper l)y 

 their position, small size and irregular shape. The above endo- 

 somal layer, so far as it is distinctly difiërentiated, greatly 

 resembles in appearance that of Acanthascus cactus (PI. XL, fig. 

 10). 



Xo diactins are found that project their ends through and 

 beyond the gastral surface except such occasional cases as may be 

 regarded as due to unnatural displacement. 



The loose feltwork of the parenchyma contains a quantity 



