FRUCTIFICATION OF CHOANEPHORA. 421 
Phycomyces, we find it stated :—** Si la spore jeune n'avait pas acquis de double contour, 
il ny a pas d'exospore percée par le tube, et le contour externe de la spore est seule- 
ment plus noir que celui du filament qui en procède ; mais si la membrane s'était déjà 
séparée du protoplasme par un contour interne, la spore, en se dilatant, brise un exospore, 
qui se décolle souvent sur tout le pourtour et continue à l'envelopper en partie." If we 
compare this description and the illustration accompanying it with those referring to the 
phenomena occurring in the case of the so-called sporangia of Chetocladium, it is evident 
that the difference in the two cases is one of degree and not of kind. 
In regard to the phenomena presented by Piptocephalis, it is evident that further 
observation is yet wanting. To those not already convinced of the necessary absence of 
eonidia, neither the descriptions nor illustrations furnished by M.M. Van Tieghem and 
Le Monnier afford satisfactory evidence of the sporangial nature of the fructification. 
That the sporoid cells are not formed successively by continuous budding, like the conidia 
of Penicillium and Aspergillus, but by the segmentation of previously continuous rod-like 
bodies, all observers are agreed; but that this affords definite proof of the sporangial 
nature of the fructification is certainly not a fair conclusion. A very similar process 
occurs in the filaments of Oidium lactis and in the ascal spores of certain Spheria, 
where the filaments or cells breaking up into a series of conidia or secondary spores, as 
the case may be, can in no sense be regarded as sporangia. There is another difficulty, 
moreover, in the way of accepting the interpretation proposed by MM. Van Tieghem and 
Le Monnier. This lies in the fact that they affirm that the spores are held together by 
a substance similar to that occupying the interspaces between the spores in the spo- 
rangia of other Mucorini. It is somewhat difficult to realize in what the similarity 
lies, seeing that in other Mucorini the special function of the material appears to be 
to ensure the separation and diffusion of the spores due to its property of swelling up in 
contact with water, whereas here it is supposed to hold them together although immersed 
in a globule of water. 
The same tendency to insist on the impossibility of the occurrence of conidial fructi- 
fication appears more or less in the account given by the same authors of the phenomena 
observed by them in JMortierella and Syncephalis. The difficulties in the way of 
accepting their conclusions regarding the nature of the fructification in the latter genus 
are precisely those alluded to in connexion with Piptocephalis. With regard to both 
genera it may, moreover, be remarked, that even if the observers be correct in denying 
the conidial nature of the fructification, it is not clear on what grounds they distinguish 
it as sporangial rather than chlamydosporous. As to Mortierella, the doubtful inter- 
pretation does not refer to sporangia, but to certain bodies which they regard as aerial 
chlamydospores. No doubt their observations regarding the occasional formation of 
such bodies beneath the termination of the parent filament would, if confirmed, be 
practically conclusive. Confirmation is, however, certainly required, as the whole 
character and history of the development is otherwise strongly suggestive of the conidial 
nature of the bodies in question. It is in this respect very significant that the aerial 
. . ehlamydospores are described as occurring under conditions of high nutrition, not on the ` 
|. same mycelium with the other recognized form of chlamydospores, and even, to a certain. — 
. SECOND SERIES.— BOTANY, VOL. I. 3M 
