316 
ZOOLOGY OF THE FAR EAST. 
The following measurements are those of a number of freshwater specimens of 
Modiola from China, Corea and Cambodia : — 
Modiola lacustris. 
Length. 
Breadth. 
Thickness 
Tung-Ting Lake, 
22-3 
8-5 
Hunan (co- types). 
lyo 
7'5 
6-5 
Tai-Hu, Kiangsu. 
135 
6-0 
I'^"0 
/ J 
=; ■ c; 
/ D 
D D 
7 " 
5 0 
13 5 
7 I 
D 0 
6-8 
J ^ 
J 
11 75 
JO 0 
11 5 
22-5 
975 
875 
18-5 
875 
7-0 
i8-6 
8-7 
6-4 
17-25 
8-2 
6-0 
Modiola camhodjensis. 
Cambodia (? co- types). 
26-25 
12-25 
9-6 
2375 
II-5 
25-20 
11-3 
The average length-breadth index of the two co- types of M. lacustris is, therefore, 
43-36, that of the Tai-Hu specimens 5017 and that of the Corean specimens, 45-38, 
while that of those of M. camhodjensis is 46-41. In each lot there is considerable 
variation in outline. The Tai-Hu shells are much the smallest. These shells vary 
considerably in colouration and four colour-forms may be distinguished, though they 
fade one into another. Some shells are uniform or almost uniform pale greenish yel- 
low, in some a dark purple colour predominates, in others the yellow is marked with 
broad longitudinal streaks of purple, while in a few the upper half of the shell is 
purple and the lower half yellow. The Corean shells are all of a dark olivaceous 
brown with a tinge of purple. 
M. lacustris is common at the edge of the Tai-Hu on small stones and on the 
roots of willows, on which it often forms large masses. We dredged a few living speci- 
mens from the middle of the lake. Colonies of the hydroid Cordylophora lacustris 
and the Ctenostomatous polyzoon Paludicella elongata were found attached to the 
masses of shells. 
Family UNIONIDAE. 
Genus Anodonta, Lamarck. 
Anodonta -woodiana (Lea). 
1834. Symplynot.i woodiana, I^ea, Trans. American Phil. Soc, V, p. 42, pi. v, fig. 13. 
1876. Anodonta woodianu, Clessin, Anodonta in Chemnitz's Conch.-Cab. ed. Kiister, p. 146, 
pi. xlviii, figs. 1,2. 
1900. Anodonta woodiana (in part), Simpson, Proc. U.S. Nat. Mus., XXII, p. 637. 
1916. Anodonta woodiana, Aunandale, Mem. As. Soc. Bengal, VI, p. 49, pi. iii, figs, ga, gb. 
