44 
ZOOLOGY OF THE FAR EAST. 
Choanomphalus japonicus. Preston. 
1916. Choanomphalus japonicus, Preston, op. cit., p. 160, pi. ix, figs. 2, 2a-2c. 
igi6. Choanomphalus japonicus var. perstriatulus, Preston, op. cit., p. 161, pi. ix, figs, i, la-ic. 
This species and its variety perstriatulus are apparently not uncommon on the 
lower surface of stones at the south end of I.,ake Biwa. They are not known from 
any other locality. 
Genus Planorbis, Guettard. 
Planorbis (Gyraulus) biwaensis, Preston. 
1916. Planorbis (Gyraulus) biwaensis, Preston, op. cit., p. 161, pi. ix, figs. 3, 3a-3c. 
Planorbis {Gyraulus) biwaensis also occurs in considerable numbers, but not very 
abundantly, on the lower surface of stones at the south end of Lake Biwa and is not 
yet known elsewhere. 
Family MELANIIDAE. 
Genus Melania, Lamarck. 
Melania libertina, Gould. 
1879. Melania libertina, Kobelt, op. cit., p. 412, pi. xviii, figs. 2-8 ; pi. xix, figs. 2-5, 8. 
1879. Melania retifera, id., op. cit., p. 416. 
1874. Melania libertina, Brot in Chemnitz, Syst. Conch. Cab, {ed. Kuster) I, pt. XXIV (Mel- 
aniaceen), p. 59, pi. vi, fig. 14. 
1874. Melania retifera, id., op. cit., p. 60, pi. vi, fig. 16. 
1902. Melania libertina, VWshxy , Proc. Acad. Nat. Sci. Phil. LIV, pp. 119, 120. 
At least two colour-forms of this species occur in the neighbourhood of Lake 
Biwa. One of these, which corresponds both in colour, in sculpture and in size with 
M. retifera, Tryon, is fairly abundant on stones in shallow water at the south end of 
the lake. A much larger but otherwise similar form occurs in ditches near Sakamoto 
on the hills above the western shore. In ditches and irrigation channels near the 
fishery station at Hikone on the eastern shore I found a large and very dark form, 
apparently the forma typica of the species. Young specimens of this form differ in 
colour from retifera, being not only darker but lacking all trace of reddish bands. 
The species appears to be distributed throughout Japan, from Hokkaido to 
Formosa. It has many phases and varieties. 
Melania multigranosa, Bttg. 
(PI. Ill, fig. 2, A-E.) 
T874. Melania niponica, Brot, op. cit., p. 338 (in part), pi. xxxiv, fig. loa {not 10). 
1879. Melania niponica, Kobelt, op. cit., p. 415, pi. xix, figs. 5-7, 10-14. 
1886. Melania {Semisulcospira) multigranosa, Boettger, Jb. d. Malak. Ges. XIII, p. 7. 
1902. Melania multigranosa, Pilsbry, op. cit., pp. 119, 120. 
This species is one of the commonest molluscs in the lake and occurs both among 
weeds and on a clean sandy or muddy bottom at practically all depths. We took two 
large and much eroded .shells at a depth of about 41 fathoms; these were the stoutest 
examples I saw. At some places in the lake, for what reason I am unable to say, 
