NOTES AND MEMORANDA. 
343 
existence of the aiithericlia — medium, light, temperature — only one new 
influence could have affected them, that of the air. M. Cornu reported 
several years ago an analogous fact * amongst the aquatic fungi. The 
result of his observations is, that the conditions sufficient to allow of 
the complete and definitive development of the antheridia and spo- 
rangia may be insufficient to allow of the dehiscence. This dehiscence 
is not a violent result of endosmose, since it remains suspended 
during long intervals, the prothallus being immersed in a liquid ; it 
is not determined by the variations of temperature or the intensity of 
light, for no change of this nature was produced in the experiment. 
If the zoospores of the Algm escape in the early hours of clear 
days in sj^riiig or summer, it is because the water which contains them 
becomes richer in oxygen under the action of the chlorophyll when 
exposed to the light. 
We are thus led to conclude that the aeration of the water gives 
to the already formed agile corpuscles a sufficient energy to enable 
them to free themselves. Heat produces analogous effects. The 
CEdogonia, which, placed in a room at 7 or 8 degrees, do not emit their 
spores, produce them abundantly when they are transferred to an 
atmosphere of 16 or 18 degrees. 
M. Cornu thinks that air or heat acts by increasing the activity of 
the plasmatic movements, and that it is in consequence of an activity 
natural to the protoplasm — which is destitute of membrane, and, in 
spite of that, capable of utilizing oxygen — that the wall of the zoo- 
sporangium is perforated.! 
CEcistes pilula . — In the ‘ Monthly Microscopical Journal,’! 
Cubitt refers to this species under the name of Melicerta pilula, which 
he gave to it “ from the fact that she fortifies the gelatinous basis of 
the theca with her own excremental jDilules.” Mr. A. W. Wills, who 
has very recently had opportunities of observing the rotifer, says : — 
“ Mr. Cubitt’s description of the singular habit of this animal is 
quite correct, but he does not appear to have observed the 2 )recise 
manner in which the remarkable operation is performed, from which 
it derives its name. It is self-evident that only a minority of the 
excrementary pellets discharged by the creature can be required or 
used to fortify its theca. Tlie larger part are whirled away from the 
vicinity of the animal, in the manner familiar to all who have ob- 
served the thecated Rotifers or the fresh-water Polyzoa ; but those 
which are utilized for building purposes are ejected between the 
rotifer and its tube or theca, and received under the lower margin of 
the ciliated trochus, where they remain for a few seconds, as if the 
animal were making sure of its proper hold, and then, by a sudden 
retraction of its body, it dabs the pellet into a proper position on the 
margin of the theca, and instantly resumes its usual condition. The 
amount and regularity of the pellets with which the tube is fortified 
varies very much. One finds occasionally an individual in which they 
* See his “Monogvaphie des Saprolcgniees (‘Ann. Sc. Nat.,’ 1872, vol. xv. 
p. 117). 
t ‘ Bull, de la Soc. Bot. de France, ’vol. xv. p. 89. (From ‘ Comptes Rendns.’) 
X Vol. viii. p. 5. 
