TRANSACTIONS OF MICROSCOPICAL SOCIETY. 
DESCRIPTION OP PLATE VIL 
To illustrate Mr. Hogg's Paper on the Development and Growth 
of the Water-snail. 
Fig. 
1. — A magnified representation of the increase and change of situation 
occurring to the yolk of egg of Limneus on the fourth day. 
2. — The change observed on the sixth day, showing the transverse fissure 
or divisional line in the mass. 
3. — The formation of the shell proceeding more rapidly, it appears on the 
sixteenth day as the larger portion of the embryonic mass. 
4. — The embryo performing its heliacal windings around the shell. 
5. — The embryo, or young animal, seen soon after it has issued from the 
shell. 
6. — The tentacles, with cilia, seen under a i-inch object-glass ; the arrows 
indicating the course of the current produced by the cilia. 
7. — The natural size and form of the shell of a full-grown Limneus. 
8. — Parasitic animal found on the body of Lim7ieus, magnified 100 
diameters. 
