Proc. Roy. Socy. of Edin. ] 
[Yol. XXIII., 1901. 
Fig. 1. — Overfed Stylonichia pustulata (see text). It is black with 
excretory granules. 
Fig. 2. — Paramecium aurelia ( x 80). Cf. with fig. 3. 
J. Y. Simpson. —Plate I. 
