EXPLANATION OF PLATE III. 
Shells of Lake Riwa. 
Lithotis japonica, Preston. 
Fig. r. — Shell of the type-specimen photographed from above, x 4. 
From Chikubushima, L- Biwa. 
Melania multigranosa, Boettger. 
2. — -Shells from L. Biwa. 
A — C. Normal shells from shallow water. 
D. Large, much eroded shell from a depth of 250 feet. 
E. Dwarfed shell taken on a sandy bottom with much weed in the Oki- 
no-shima channel at a depth of between 12 and 20 feet. 
Melania niponica, Smith. 
3. — Shells from L. Biwa. 
A. Normal shell from near Otsu. 
B. Shell of large, heavily sculptured type from Chikubushima. 
Melania biwae, Kobelt. 
4. — Shell from Chikubushima. 
Valvata biwaensis, Preston. 
5. — Shell of type-specimen from deeper parts of L. Biwa, x 4. 
Valvata annandalei, Preston. 
6. — Shell of type-specimen from deeper parts of L. Biwa , x 4. 
Cristaria plicata (Leach). 
Figs. 7, 8. — Young shells from L Biwa. 
The shell shown in fig. 7 is unfortunately cracked. 
Anodonta woodiana (Lea). 
,, ga, gb. — Right valve of specimen from vSeta, L- Biwa. 
Corbicula viola, Pilsbry. 
Fig. 10. — Typical shells from comparatively .shallow water. 
A. Full-grown shell. 
B. Half-grown shell. 
,, II.— Dwarfed shell taken in the northern part of the lake at a depth of over 
260 feet. 
Corbicula sandai, Reinhardt. 
12.— Small shell from the Oki-no-shima channel. 
Sphaerium heterodon, Pilsbry. 
13- — Shell from a ditch at Hikone, x 2. 
Pisidium casertanum (Poli). 
,, 14. — Shell of the form lacustris from the deeper parts of L. Biwa. 
Except when it is otherwise stated, the specimens have been photographed of the natural size. 
Tn the case of specimens of Melania chalk was rubbed on the surface before the shell was photographed, 
iu order to show up the sculpturing. 
