Japanese Species of the Genus ('orbiciUa. 
527 
Corbicula leana Prime. 
(Plate XXII, figs. 8-1 1.) 
i}Sf)4. Corbicula Lcaiia, Prime, op. oil., p. 68, fig. 14. 
1870. Corbicula Leana. rrimc, op. cil., p. ij2. 
1877 Cyrena [Corbicida) Leana, von Martens (in pt.) op. cil. p. iii). 
1878. Corbicula pexata, Reinhardt {nec Prime) op. cil., p. Kjj, pi. \-, fig. (). 
1878. Corbicula Leana, Clessin, op. cit., ]). 169 pi. XXX, figs. 5, b. 
1879. Corbicula Leana, and Cyrena pexata, Kobelt, op. cit., pp. 443, 440, pi. XX, fig. 2. 
1907. Corbicula leana, Pilsbry, op. cit., j). 15-5. pi. vii, figs. 5, 6. 
1907. Corbicula orthodonla, id., ibid., p. 15O, pi. vii, figs, i, 2. 
With a paratype of C. orthodonta Pilsbry and a large series of specimens from 
Yokohama, Yodogawa, Osaka, Hinga, Kiushiu Island and Lake Biwa near Otsu, 
Omi, I can find no differences between Prime's C. leana and Pilsbry's C. orthodonta. 
Prime's description was apparently drawn up from medium-sized shells, while Pilsbry 
described his new species from large, full-grown shells. In the large series before me 
I have shells which correspond to both, and the shells of intermediate sizes bridge 
over the gap between them. In Reinhardt' s collection I have also seen shells 
identified as C. pexata Prime and referred to under this name in his paper cited ; 
these are also specimens of C. Leana. 
Prime's and Pilsbry's descriptions are very detailed, and I have nothing furthei 
to add to them. 
Relationships: — C. leana Prime is closely allied to C. fiuminea (Miill.), and is 
probably an insular form of this Chinese species, but the large size, the truncate 
posterior side and the sculpture are quite sufficient to distinguish it as distinct. Of 
the other Japanese species it is allied to C. atrata Reinhardt. 
Pilsbry's inclusion of ('. reiniana and C. stvaminea in the .synonymy of this 
species is certainly incorrect. 
var. sadoensis (Pilsbry). 
(Plate XXII, figs. 12-14.) 
igoi. Corbicula sadoensis, Pilsbry, Proc. Acad. Nat. Sci. Philadelphia, p. 40!). 
1907. Corbicula sadoensis. Pilsbry, op. cit., p. 158, pi. vii, figs. 15, 16. 
With a paratype and large series of Pilsbry's sadoensis from Sado Island 
collected by Messrs. Faber and Voigt, in 1894 and now preserved in the Hamburg 
Museum, before me I find that this is only an insular variety of C. leana. 
The external striations on which Pilsbry lays so much stress are very variable, 
and in shells from the same locality one finds shells having the striae either 
very densely arranged as in the type of sadoensis, or more widely apart as in leana. 
The umbones also are, in unworn specimens, similar, and so are the hinge and 
the nymphs. The shells are slightly smaller, and this along with the somewhat closer 
striae are the only two distinguishing characters of the variety. The species is 
somewhat variable in form, shells from the same locality often vary considerably 
in outline. 
