HOMORUS, WEST AFRICA. 147 



23. II. PATTALUS Pilsbry, n. sp. PI. 59, figs. 65, 66, 67, 68. 



Shell turrited, with rather straight spire, only very slightly 

 attenuated above, terminating in a large, very obtuse apex; 

 thin but moderately solid; yellowish olive, profusely and 

 irregularly, obliquely streaked with brown and blackish- 

 brown, the embryonic 3% whorls clear olive. Surface some- 

 what glossy showing a weak, coarse striation in places, and 

 when highly magnified a dense, wavy spiral striation, weakly 

 and shortly plicate below the sutures. Whorls 9%, weakly 

 convex, the first forming the rounded, half-globular summit; 

 first 3y 2 to 3% whorls smooth and glossy, with only faint 

 subsutural crenulation, cylindric, terminated by an oblique 

 dark streak. Last whorl sharply angular in immature shells, 

 becoming rounded in adults, the angle still noticeable in front 

 of the aperture, but continued merely as a dark line. Aper- 

 ture acutely ovate, the columella very concave, very narrow, 

 truncate ; parietal wall not at all calloused. Length 37, diam. 

 9 mm. ; length of aperture 9, diam. of third whorl 3 mm. 



West Africa: Cape Palmas, Liberia, (A. N. S. P.). 



Distinguished by its large smooth embryonic shell, obsoles- 

 cence of the peripheral keel in adult shells, and for the small 

 number of whorls in its length. 



24. H. NIGELLUS (Morelet). PI. 57, fig. 34. 



Shell subulate, slender, finely striolate, glossy, dark brown. 

 Spire elongate, the apex rather mucronate ; suture impressed, 

 in places denticulated by the strias. Whorls 12, plano-convex, 

 the last one small, obtusely angular below the middle, nearly 

 one-fifth the total length. Columella arcuate, obliquely trun- 

 cate. Aperture small, semioval, whitish within; peristome 

 simple, thin, unexpanded. Length 17, diam. 3 mm. (Morel.) 



West Africa : Presidio of Pungo-Andongo, in moss on the 

 banks of the Rio Casabale (Welwitsch). 



Achatina nigella MOREL., Voy. Welwitsch p. 80, pi. 5, f. 

 3 (1868). PFR., Monogr. viii, 287. 



The shell is engraved with fine, oblique, irregular striae, 

 which become more emphatic and even pliciform near the 



