ORCAXS OF NUDIP.RAXCHl.VTA. 



341 



round chambers opening into the former ; the smaller, peri- 

 pheral chambers produce the ova. That the conditions are as 

 above, and not so that both spermatozoa and ova are produced in 

 the small chambers, and that the earlier developed spermatozoa are 

 then stored in the central chamber, is proved by the fact that in the 

 central chamber there are spermotozoa in all stages of develop- 

 ment, as in the peripheral chambers there are ova in all stages. If 

 we suppose that such an acinus as Caliphylla possesses were to be- 



Fig. I. 



come Jiiodified so that the egg-production became localised at 

 certain points in its wall, and that, later on, these points grew 

 outwards to form sacs, opening into the old acinus, we readily 

 see that the whole " unit " or grappus (central male chamber 

 plus peripheral female chambers) of Doto- must be homologous 

 with a single acinus of Caliphylla. 



The hermaphrodite gland stretches from the region of the 

 auricles of the heart back to the hinder end of the hsemocoel ; the 



