1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 159 . 
1. Columella toothless. Shell strongly compressed dorsoventrally, the lip more or 
less expanding and winged above and below in the fully developed form. 
Leneticl 3d to. 28 ities cet autre mies She ee eee Neritina oweniana (Wood). 
Columella having an inwardly directed tooth above the middle, visible in an 
oblique view in the mouth. Shell small, subglobose.................... pA 
2. Spire extremely low; about 144 whorls visible. Suture in form of a semicircle 
ending in an apical pit. Greatest length about 7 mm. 
Neritina glabrata Sowerby. 
Spire slightly raised; about 2 whorls visible. Suture in form of a spiral around 
the apical pit. Greatest length about 9 mm. | 
Neritina adansoniana (Récluz). 
Subgenus Virra Mcerch 
Neritina subgenus Viita “ Klein’? Marcu, 1852, ‘Cat. Conchyl. Yoldi,’ I, p. 166. 
Type by designation of H. B. Baker (1923): Nerita virginea Linneus. 
Scapha “ Klein’? Marcu, 1852, ‘Cat. Conchyl. Yoldi,’ I, p. 166. As asynonym 
of Vitta. Type: Nerita virginea Linneus. 
Shell with prominent spire, the aperture not enlarged; in the African species 
known to us the columellar margin of the aperture toothed or serrulate. 
Radula: unpaired central with a thickened rim; inner lateral roughly triangular, 
not especially large or broad, with well-marked indentation at outer edge for articula- 
tion with the innermost of the two small, middle laterals; of the two fused outer 
laterals, the inner one is well developed, while the outer one has shallow reflections 
and well-marked, heavy major and minor cusps; all marginals with prominent serra- 
tions on outer side and at the tip. | 
Neritina (Vitta) glabrata Sowerby 
Plate X, Figures 1-40 | 
Neritina glabrata SowERBY, 1849, ‘Thesaurus Conchol.,’ IT, p. 535, Pl. cxv1, figs. 
256-263 (described from an unknown locality). Tryon, 1888, “Manual of Conchol.,’ 
X, p. 56, Pl. xviui, figs. 2-5. Daurzenpere, 1812, Ann. Inst. Océanogr. Monaco, 
¥,-3; p. 74; 
Neritina (Smaragdia) glabrata Sowerby. E. v. Martens, 1879, in Martini and 
Chemnitz, ‘Syst. Conch. Cab., II, 10, Neritina,’ p. 253, Pl. xx11t, figs. 32-34. 
Neritina (Vitta) glabrata Sowerby. H. B. Baker, 1923, Proc. Ac. Nat. Sci. 
Philadelphia, LX XV, p. 187, Pl. x, fig. 4 (radula). 
Neritina webbet Ri&kciuz, 1850, Journ. de Conchyl., I, p. 151 (as a synonym of 
glabrata Sowerby). 
Neritina glabrata var. senegalensis ‘Duclos’ H. B. Baker, 1923, Proc. Ac. Nat. 
Sci. Philadelphia, LX XV, p. 137 (as a synonym of glabrata Saket 
Creek of Kitompo [=Kitombe] and entrance to the HAPBOE of Banana 
(Gruvel Coll.). 
The species is known Alsi the coast of West Africa from Gambia to Angola. 
San Antonio: collected in very large numbers at Pt. Padréo upon 
sand banks, also on the shore where it is only slightly exposed to the 
waves (H. Lang Coll.). 
