110 MR. H. M. WARD ON THE STRUCTURE, DEVELOPMENT, 
tification, I have been unable to follow out the further steps in the development of these 
cells (or oogonia, as they noware). In so far, however, as very numerous examinations of 
separate specimens are capable of throwing light on the matter, the following appears to 
be the order of events." The author then describes the origin of “ numerous slender- 
branched filaments from the neighbouring cells of the disk. Some of these become dilated 
at the extremity; and the large terminal cell becomes applied and closely adherent to an 
oogonium (pl. xlii. fig. 12). These filaments appear, as a rule, to arise from the under 
surface of the disk ; and those which are developed into pollinodia are usually attached 
to the oogonia towards their bases. The contents of the terminal adherent cell appear next 
to be emptied into the oogonium, and to blend with the oosphere. Owing to the reason 
previously mentioned, this process has never been actually observed to occur.” 
The “ oogonium," containing an **oospore," is then stated to become loose, and to 
remain for some time among the débris of the thallus, and finally give rise to “ zoospores,” 
which produce, eventually, new Algal disks. 
Two views are possible of the above series of events, assuming that Mycoidea and the 
Alga observed by me are generically the same. | Either Cunningham discovered a female 
organ of reproduction which I have not seen, and which becomes fertilized and produces 
zoospores as described by him, or he confounded the organs already described. In offering 
the following criticism, I shall, for the sake of argument, assume that the А1о are 
identical; otherwise the remarks, presented in no captious spirit, are of little value. It 
seems extremely unlikely that such an organism as this Coleochete-like Alga would pro- 
duce three sets of zoospore-like motile bodies agreeing in all essentials of size, colour, 
cilia, &е. ; hence it is not probable that the asexually produced zoospores of my figs. 39 
to 47 play the part of antherozoids towards an oogonium, which again produces zoospores 
of similar size, constitution, &c. My observations confirm those of Cunningham respecting 
the production of zoospores from the ovoid bodies supported on the heads of upright fila- 
ments (figs. 2, 4, 5, pl. xlii. Cunn., & my figs. 21 to 38); and I have seen the zoospores 
from the thallus-cells (my figs. 39 to 47) so frequently, in some instances scores of the 
cells (fig. 12) bursting one after another in the field of microscope, and in no case been 
able to detect any thing like a conjugating process, that I can no longer consider it 
doubtful. 
At Pl. XIX. fig. 19 a, I have drawn one of these zoospore-containing cells of the 
thallus, seen from the under side, together with several of the rhizoid-like outgrowths of 
the same order as those of figs. 12 and 17 & 18; and it might be suggested that these are 
possibly of the nature of Cunningham's “ pollinodia ;” but it is obvious that the contents 
of the zoospore-producing cell have already commenced to form the zoospores at a period 
when the rhizoids are certainly not emptying anything into the cell; the attachment of 
the * rhizoids " cannot, therefore, be regarded as of a sexual character. Moreover in most’ 
cases I find no such production of rhizoids so close to the cell, and the latter produces its 
zoospores without any approach of such bodies. 
It is sometimes very difficult to determine exactly the nature of the basal cell of the 
* fertile hair," when examining the surface of the thallus; from the thickness of its walls, 
dense orange-red contents at first, and other circumstances it might possibly be mistaken 
