')SC) T. TKEDA : 



not refer to the latter author. In exaniiiuDg Roule's figureB (31 

 and 32), eertain nucleated cells are seen dispersed in the hlasto- 

 eœlic cavity. They are said to he the inner ends of some elong- 

 ated l)Iastonieres. In the endnyos of F/iorom's Jjimat, similar 

 ])i'ocesses ai'e indeed discovered protruded from some hlastomeres, 

 hut they nerver contain the nucleus in their distal or inner ends : 

 the nucleus helonuinu' to these elono-ated hlastomeres is situated 

 also jK'ripherally as in other normal hlastomeres. The ])lasmic 

 corpuscles which have, as I have described in the present pajX'r, 

 arisen from suhse(iuent fragmentation of certain elongated Idasto- 

 nieres, exist very distinctly as se])arate bodies disj)ersed in the 

 hlastocœlic cavity. 



In his ])resent pajx^r Houle reiterates his former views al)out 

 the dual origin of the mesenchyme-cells. Upon this point I have 

 alreadv oiven mv own ideas, and here I have to add onlv the 

 following remark : 



Though IvOULE, like Schultze ('97) has i-egarded, the nejdiri- 

 dial ])it as the origin of the ventral ])0uch of Actinoirocha, the 

 suhse(iueut development distinctly shows that the two structures are 

 entirely inde]X'ndent of each other in their origin. 



I can not refrain from douhtino' the correctness of Roule's 

 observation that the larva studied by him j)0ssessed at no time 

 during the swinuning life any septal membrane in the body-cavities. 

 They are structures which in the other forms of Actinoii'ocha 

 have l)een so accurately demonsti'ated hy ])revious oljservers. The 

 techniciue enijdoyed by the author may ]ierhaps be found to be 

 faulty in this respect. The fine threads denoted Ijy " brides 

 mesenteriques " in his figures (."jy, 7'"), and 97) seem to have arisen 

 from the j^ieces of the otherwise continuous postral septum broken 

 hv the knife-blade in microtomizing. 



