106 BOTRYDIUM GRANULATUM. 



regards the author's statement that the membrane is double, one 

 cannot say nay. I did not notice that myself, but I would venture 

 to suppose the possibility that he may have mistaken the boundary 

 of the shrunken-in protoplasmic contents — the so-called " pri- 

 mordial utricle " — for an inner membrane. In several algaa this 

 is seen, and looks very like a membrane. Still, doubtless, many 

 algaa have laminated membranes. That immediately investing the 

 contents remains generally firm, the outer older laminae removable 

 or "dissolvable." The author has seen "zoospores," but while he 

 calls them by that name he seems to regard them functionally as 

 spermatozoids, and that these travel across from certain of the 

 " vesicles" by the under-ground connecting tubes to certain other 

 "vesicles," there to fertilize certain other larger "grains." It 

 would not befit one who has not followed out his observations to 

 say nay again to this ; but the view does not seem to have the 

 ground of analogy. But it would not on that account be untrue. 

 It would seem to be the case where spermatozoids occur that 

 they are themselves generated within a more or less specialized 

 structure, and, from which set free, that they proceed to act 

 upon what the Germans would call a " Befruchtungskugel " — a 

 specially differentiated portion or mass of protoplasmic matter, 

 when fertilised an oospore — and not that in the same or an adjoining 

 cavity one portion of the contents becomes spermatozoids, another 

 the future oospore. Not only is the " oospore " thus a specialised 

 body, but it is enclosed (singly or several) within a specialised 

 " oogonium." But the Conjugates are examples of germ-cell and 

 sperm-cell (if you admit in that group the applicability of these 

 terms), mutually co-operating, whilst the spore is not in a specialised 

 " oogonium " (so as to say), but both factors in the process occupy 

 a common cavity. The author's views may not, indeed, be impos- 

 sible. If true it would degrade Botrydium considerably below 

 Vaucheria, where the antheridia and the oogonia are highly dif- 

 ferentiated. The author says he has not seen anything like the 

 " conjugation" of Vaucheria. This is surely a misapprehension 

 of his, for " conjugation" does not take place there (comparable to 

 Spirogyra or Mesocarpus, &c). The probability, I venture to 

 think, is rather he has seen the zoospores (zoogonidia Aut.), not 

 spermatozoids. Doctor Itzigsolm is stated to have seen zoogonidia. 

 Since I came home I havn't had time to try and work up where. 

 If the author's views were correct the larger grains would, I 

 suppose, have necessarily to be regarded as its " true fruit," for 

 they would be fertilised protoplasmic masses. If, on the other hand, 

 the motile bodies be only zoospores, this plant, as regards our know- 

 ledge of its history, would remain much in the position of several 

 other alg£e — say, for instance, Characium, &c. As, however, the 

 contents have been seen simultaneously segmented into individual 

 portions, if any fertilization occurs it would be more probable that 

 they it is that would be acted upon by spermatozoids. 



