3i8 
ZOOLOGY OF THE FAR EAST. 
The following are the measurements of three specimens : 
Thickness. 
975 
77 
12-8 
1375 
The epidermis varies in colour from pale olivaceous to almost black. The inner 
surface is tinged with violet. 
The shells from the Tai-Hu perhaps represent a dwarfed phase of the form figured 
by Heude under the name C. largillierti var. A, which also came from a lake in the 
Yangtse delta. I have examined a series of small shells from the Tung- Ting lake in 
Hunan named, apparently by von Martens, " Corbicula fluminea, Miill." These 
shells are hardly larger than those from the Tai-Hu, from which they differ only in 
being on an average a little broader in proportioft, and in having the ridges on the 
external surface a little more regular. They differ from the normal C. fluminea in 
their smaller size, thicker shell and stronger teeth, but the eastern species of Corhicula 
are still in great confusion and so far as those of China are concerned, Pilsbry {op. 
cit., supra, p. 153) says with justice, " In dealing with the Chinese species Pere 
Heude has attempted to name every local form, a task I believe to be practically 
impossible, and if accomplished the result would be absolutely useless to any other 
zoologist from the impossibility of again recognising the forms." 
The species occurs in great abundance on the muddy bed of the Tai-Hu, where 
it is markedly gregarious. It is widely distributed in the southern part of Japan and 
has been recorded from Tonquin. 
Two small shells (living) of this genus were dredged off the island Si Dong Ding, 
but as both are broken I do not attempt to name them specifically. 
Note on the Supposed Occurrence of the Genus Arc a with Freshwater 
Neumayr ' in his account on the freshwater molluscs collected in China by Count 
Bela Szechenyi describes a true Area under the name Area granulosa var. minuta. 
Apparently granulosa is a slip for granosa. He states that a single shell of this form 
was found, with specimens of Bithynia, Vivipara, Melania and Corbicula, in a recent 
deposit 50 miles inland from the mouth of the Yangtse. Area granosa, Linn, is one 
of the commonest and most characteristic molluscs of brackish water on the coasts 
of India and other parts of south-eastern Asia and is always more or less dwarfed 
when living in water of low salinit}^ In the sea it attains a large size. There are 
specimens from the Nicobars in the collection of the Indian Museum over 75 mm. 
broad. In the inner parts of the Chilka Lake on the eastern coast of India, on the 
other hand, where the water is never more than slightly salt, Mr. Kemp and I found 
no living shell more than 26 mm. in breadth. We have discussed the living and sub- 
Genus Sphaerium, Scopoli. 
MOI,I.USCS IN THE YaNGSTE. 
Wiss. Ergebn. Raise. Bila SzSchenyi I, Sussw.-MolL, p. 641, pi. i, fig. 4 (1887). 
