xlvi 
Journal of Proceedings. 
“ The water contained a considerable number of Rotifers, mostly of the 
species I took to be Pleurotrocha gibba, and a few Rotifer vulgaris. 
“In a specimen of Vauclieria dillwyni, Ag., gathered from a damp cart- 
rut on March loth, I found a few capsules si mil ar to those described also 
containing Rotifers, having the same appearance as those found in the 
pond. On placing the plant in water I found it on the following morning 
discharging motile spores from the extremity of its threads, a character 
common probably to all the species of Vauclieria. Xow the question that 
puzzled me extremely was, how did the Rotifers gain admission into the 
vigorous green Alga 1 and what gave rise to the remarkably large capsules 
Fig. 2.—The Rotifer Parasite on Vauclieria * 
invariably tenanted by these creatures ? Is it possible that the Vauclieria 
is selected as a favourable nidus, and the abnormal growth produced by 
some stimulating action on the same principle as Cynips occasions the 
galls on the oak-leaf ? though in this case it would be impossible for the 
large eggs to be inserted into the plant, not to mention the fact that the 
eggs are apparently all produced by the animal after its inclosure in 
the capsule; for I should mention that in the youngest capsules the 
creature is much more slender in form than it afterwards becomes, and 
the eggs are quite rudimentary. If the plant is really selected as a fit 
* The Club is indebted to Mr. Lister’s kindness for this cut, engraved by Messrs. West, 
Newman & Co., from bis own drawings.—E d. 
