440 



"conjugation of Protophyta" is a phrase that suggests that Dr. Beard 

 means something very ditierent by "Protophyta" or by "conjugation" 

 from what the rest of morphologists mean. The latter suppositions 

 seems the more probable as will be shown. 



2) On page 254 he writes "the primitive form of sexual repro- 

 duction or conjugation, and by either of these terms may be assumed 

 the union of at first like zygotes and afterwards of unlike" etc. But 

 the "union" of "like zygotes" or of "unlike zygotes" is to me an 

 incomprehensible juxtaposition of words. That gametes may unite to 

 form zygotes I am able to understand but the union of zygotes is a 

 new conception , savoring of transcendental morphology. Certainly 

 the definition of conjugation as consisting in the union of zygotes is 

 unique. 



3) And on page 241 I find this statement "the whole of the 

 cells of the gametophyte must be looked upon as morphologically 

 equivalent, some becoming differentiated as vegetative organs by steri- 

 lity, others retaining the primitive character of becoming conjugating 

 gametes". I can not understand how this statement can be reconciled 

 with the well-known facts of the absolutely non-sexual nature of such 

 plants as the Schizomycetes and Cyanophyceae, nor with the facts of 

 the Ulothrix life-history, where gametes are clearly seen to be modifie 

 gonidia. When one knows that the formation of special reproductive 

 cells is not necessary for the perpetuation of the species (e. g. 

 Cladothrix) ^) it is certainly an inversion of the facts to maintain 

 that in gametophytes vegetative cells are always sterilized gametes. 

 To state in the light of known facts that all the cells of an Oedo- 

 gonium filament are either gametes or sterilized gametes seems to be 

 gratuitous. I suppose it would be replied that the condition of Spiro- 

 gyra or Mesocarpus is the original one to be traced back in turn to 

 the Desmidium type where single - celled individuals conjugate. But 

 this remains to be proved and the Ulothrix life-history indicates a 

 very different interpretation as equally probable. And how would it 

 be in Sphaeroplea? I advise any one who is led to accept this in- 

 verted theory — that in the gametophyte — vegetative cells are steri- 

 lized gametes — to observe closely the life-history of this last named 

 plant. 



Furthermore it will be interesting to see how Beard proposes to 

 explain those plants which have a direct segmentation of the syn- 



3) According to Billet this genus is known under peculiar and rare 

 conditions to form spores. 



