No. 3.] SPERMATOPHORES. ^05 



address ^ to the Royal Microscopical Society, referring to Plate's 

 account, he says : " It is not necessary to comment further on 

 this strange theory than to say that Gosse has seen intercourse 

 take place at the cloaca in the case of Brachioims pala ; M. E. F. 

 Weber, in that of Diglena catellina ; and Mr. J. Hood, not only 

 in Floscularia ornata, SynchcEta gyrina, Eitchlanis triquetra, and 

 Melicerta tiibicolaria, but also more than a score of times in 

 Hydatina seiita itself." 



"The frequent presence of spermatozoa in the perivisceral 

 cavity" is, however, one of "the doubtful points" for which 

 Dr. Hudson offers no explanation. No opening is known by 

 which they could reach this cavity. " Neither the oviduct, nor 

 the cloaca, is known to have an opening into the perivisceral 

 cavity, and yet the spermatozoa in several species have been 

 seen in that cavity, adhering to the outside of the ovary. How 

 did they get there } " 



Plate's observations answer this question, and it will not do 

 to dismiss them as "a strange theory," since the same strange 

 thing is reported from so many different sources. 



1 On Some Doubtfid Points in the Natural History of the Rotifera. Journal 

 Royal Microscopical Society, February, 1 891, p. 6. 



