306 J. Beard 



of four new species, the sexual conditions are considered for several 

 speeies, and it is concluded that the hermaphroditism of the genus 

 is protandrous in nature. Wheeler on pag-. 277 speaks of this re- 

 sult as affording »a simpler — and I trust also — a more satisfactory 

 explanation of the sexual peculiarities of Myzostoma^ than has been 

 given by preceding authors«. 



For one species [M. pulmnar] the validity of this Interpretation 

 is disputed, as will be seen anon, by Prouiio (7), and ray researches 

 lead me to deny it for another [M. glabnim). The explanation 

 offered by Wheeler is, as a matter of fact, identical with that 

 previously adopted by Naxsen, who was restrained from carrying 

 it to the extremes, which have seemed possible to the former writer, 

 by the hard faets of the anatomy of the complemental males (or, as 

 Prouho aptly terms them, the dorsicolous forms), and by his re- 

 cognition of the dioìcious characters of some of the cysticolous species. 



As Wheeler has been able to prove that in certain cases (for 

 it has not, as will be apparent later, been shown to be invariably so) 

 Nansen's »problematical organs« are ovarian in character, he has 

 obtained a groundwork of fact, which might be of eonsiderable 

 importance, if it really possessed all the bearings he ascribes to it. 

 Nansen's organs were viewed by their discoverer as primordial 

 ovaries, and, with the modification of this phrase to primordial or 

 original sexual organs, I should now like to express agreement 

 with him. 



Before proceding to an examination of the bearings of the 

 resnlts of my own studies of M. glahrum on Wheeler's conclusions, 

 two other points, among those treated of by him, may be referred to. 

 These are the systeraatic position of the genus and the supposed 

 sensory nature of the structures identified by Nansen as glands. 



Although since 1884 von Graff may never have openly declared 

 his Position towards the view of the Chsetopod relationships of the 

 genus — as established in my dissertation and as now adopted by 

 Wheeler — he has recognised in correspondence with myself that 

 his own former opinion would require modification, and by implica- 

 tion he has adopted their Chaitopod affinities in his mouograph on 

 the genus Spinther^ as Wheeler himself notes. It is necessary to 

 call attention to this, for on pag. 269 the latter author writes: — 

 »two of the principal authorities on the Myzostomidse, von Graff 

 and Nansen, bave never accepted this view« (of their Chgetopod 

 affinities). 



