1927] Pulsbry-Bequaert, The Aquatic Mollusks of the Beigiin Congo 161 
black tones render them rather conspicuous. It is only on closer investi- | 
gation that one notices their extremely delicate and diversified patterns.” 
(Hi), 
Neritina (Vitta) adansoniana (Récluz) 
Plate XIII, Figures 1-15 
Nerita adansoniana R&civz, 1841, Rev. Zoolog. Soc. Cuviér., p. 313 (type lo» 
cality: estuary of the Senegal). 
Neritina adansoniana Récluz. REEvn, 1856, ‘Conchol. Iconica,’ IX, N erttina, 
Pl. xxx11, figs. 145a-b. Tryon, 1888, Manual of Conchol.,’ X, p. 40, Pl. x11, figs. 
50-51. 
Neritina (Neritxa) adansoniana Récluz. E. v. Martens, 1879, in Martini and 
Chemnitz, ‘Syst. Conch. Cab., II, 10, Neritina,’ p. 129, Pl. xrv, figs. 22-23. C.R. 
Batresr, 1913, Ann. Soc. Zool. Malacol. Belgique, XLVII, (1912), p. 108. 
Neritina (Vitta) adansoniana Récluz. H. B. Baxer, 1923, Proc. Ac. Nat. Sci. 
Philadelphia, LX XV, p. 137. 
Neritina sangara MORELET, 1848, Rev. Zoolog. Soc. Cuviér., p. 355 (type locality: 
rivers of the coast of Senegal). 
Banana (P. Hesse Coll.). 
The species is known along the West Coast of Africa from Senegal to Angola. 
Banana: these snails were found in abundance crawling on alge- 
covered banks of the creek of Banana toward Moanda, near the “Ile des 
Pécheurs”’ (H. Lang Coll.). 
This species is far dess variable in color pattern than JN. anita 
The ground color is either light mineral gray or light pinkish cinnamon, 
the markings black. Most of the specimens seen may be assorted thus: 
(a) Ground tint light mineral gray 
i 1. Fine axial lineolation strewn with black-shaded spots of the ground. 
Pl. XIII, figs. 1-3, 6. : 
2. Spots coalescent into oblique stripes. Pl. XIII, figs. 4, 5. 
(b) Ground tint light pinkish cinnamon; usually no lineolation. 
3. Spots and bands of the light ground at periphery and base, elsewhere 
black markings. Pl. XITI, figs. 7-11. 
4. Blackreduced to bandsaboveand below periphery. Pl. XIII, figs. 13, 14. 
Sometimes pattern No. 1 has pinkish ground color. There are also 
a few transitions between each contiguous pair of color forms. 
The usual length is 9 mm. | 
“The much darker and more inconspicuous Neritina (Vitta) adan- 
soniana is found only on the right, or Belgian, shore of the Congo, just 
as the slightly smaller and brighter N. (V.) glabrata occurs apparently 
on the left, or Portuguese, bank. N. (V.) adansoniana is evidently 
more adaptable to different degrees of salinity, as well as to the more or 
less strong action of the waves. It seems remarkable that it should thrive 
equally well on the muddy shores of the Ile des Pécheurs at the very 
