Proc. Roy. Socy. of Edin. ] 
[Vol. XXIII., 1901. 
Fig. 3. — Paramecium caudatum, dorsal aspect ( x 80). Cf. witli fig. 2. 
*• 
x o 
Fig. 4. — Double Paramecium monster at interval of 3 days. Observe elongated 
cilia in the anterior region, c.v., contractile vacuole ; n., nucleus ; 
o., oral aperture. 
J. Y. Simpson.— Plate II. 
