180 I. IJIMA : HEXACTINELLIDA. I. 



work, in some of the specimens of E. aspergillum examined by 

 Schulze (/. c, p. 67). 



The same investigator also stated that he had discovered 

 numerous sperm balls in various stages of development in several 

 specimens of Farrea occa [1. c, p. 285). 



It is somewhat surprising to me that, although the different 

 Hexactinellid species histologically studied by me are not few 

 in number, yet scarcely a single case, in which either of the 

 sexual products was indisputably developed, came under my 

 observation. In the case of E. marshalll, I have made special 

 search for them in numerous specimens which were obtained at 

 various dates extending over the four seasons of the year ; but 

 the results were quite unsatisfactory, as will be seen in the sequeL 



As regards the viale elements, I must say I am simply 

 quite in the dark. 



I should mention here certain peculiar structurels — small, 

 irregularly rosette-like groups of minute, radially arranged, rod- 

 like bodies (PI. V, fig. 44) — which at times caused me to suspect 

 that they might represent a stage in the spermatogenesis. 

 Exactly the same structures had also been discovered by me in 

 a specimen oî Acanthascus cactus. In E. marshalll I have found 

 them in sections of a single specimen, which was killed with 

 absolute alcohol, Jan. 4, 1896 ; they seemed to be present only 

 in the interior of chambers, sticking to the residue of the flagella. 

 The groups are somewhat variable in size (measuring about 

 o /^ in average dia.) and considerably so in the number of the rod- 

 like bodies in each. The single rod-like bodies are thin and 

 usually somewhat narrowed at both ends ; they are less than 

 2 fi in length, some being appreciably thicker than others. Their 



