Leptoplax doederleini (Thiele, 1909)

(Figs 19–21)

Notoplax döderleini Thiele 1909: 39, pl. 5, figs 32–38; Kaas & Van Belle 1980: 40; 1998: 64; Xu 2008: 458.

Notoplax (Notoplax) doederleini; Van Belle 1982: 478, fig. 4.

“ Notoplax ” doederleini; Saito 1998: 160, fig. 2N; 2000a: 102.

Leptoplax doederleini; Saito 2000: 21, pl. 10, fig. 6; 2001: 200, fig. 14; 2006: 217; 2017: 54, 737, pl. 10, fig.8; Sirenko & Saito 2017: 460, figs 9–12, 43D. Type material. Holotype ZMB Moll. 102017.

Type locality. Kajiyama (=? Katsuyama, Tokyo Bay), Japan .

Material examined. South China Sea, Hainan, Xincun, corals and Zostera sp., 0.5 m, 1 spm, BL 10.5 mm, 21.04.1958.

Distribution. From Pacific coast of central Japan to Okinawa, Hong Kong, Hainan and northern Vietnam, 0– 20 m.

Remarks. Van Belle (1982) reported this species from Hong Kong for the first time. Specimens from Hainan (Fig. 20D, this study) and from Vietnam (Fig. 11, Sirenko & Saito 2017) differ from specimen from specimens from Hong Kong (Fig. 4, Van Belle 1982) by the shape of the central tooth of the radula. The studied specimen (BL 10.5 mm) has a radula that is 3.5 mm long with 37 transverse rows of mature teeth and 11gills extended from valve V to valve VII. Slit formula of this specimen is 5/1/8.