NOTES ON THE PALUDINA-SPECIES OF JAPAN. 



S5 



and must therefore be looked upon as varieties of the latter. 



In identification I have found it of great importance to bring into 

 consideration the form of young shells in different stages of growth, 

 either found free or taken from within the body of mother shells. 

 For, the young have characteristic shape for each species and are very 

 persistent in their characters in comparison with adults. 



I. Paiudina stelmapliom (Bourgnignat). 

 Pl. V, figs. 1—4. 

 The specimens which I refer to this species, have characters essen- 

 tially agreeing with the original diagnosis of Boqrgnignat and with the 

 description given by Kobelt (loc. cit.. p. 122). The principal characters 

 are as follows : 



Shell swollen, egg-shaped, thin, smooth, with a greenish epidermis, 

 umbilicated. Spire low, with an obtuse apex usually worn out in old 

 specimens. Whorls quite roundeil, separated by deep sutures ; each 

 whorl wound round with three punctured lines, which, though some- 

 times extremely fine, are always present and easily visible to the naked 

 eye. In young individuals the lines are often beset with fine hairs. 

 These punctured or haired lines seem to be peculiar to this species ; they 

 are not found in any other Japanese species of Paiudina, in which we find 

 raised lines instead. They were described by Kobelt but were omitted 

 in his figures. Aperture nearly round, obtusely angled at the upper end. 

 Edge of outer lip turned out, consisting of a thin epidermis which is 

 connected with the inner lip by a thin callosity, margined with a black 

 band: In fully grown specimens, the surface of the body- whorl is 

 provided, especially close to the outer lip, with some elevated ribs 

 besides the several lines of growth Interior of the aperture bluish- 

 colored. Height 43 — 58 mm. Diameter 26 — 36 mm. Aperture 22 — 

 30 mm. long, 19 — 23 mm. wide. 



Specimens of this species very often present hammered-like sculp- 

 ture on the surface (P. umiliata, Beeve). As was correctly re- 

 cognized by Kobelt, these should not however be made into a distinct 



