TRICHODINA. 185 



Whorls 9%, rather flat, the last less than one-third the total 

 length; columella very arcuate, obliquely truncate. Aper- 

 ture oblong-oval, dirty whitish inside; peristome simple. 

 Length 33, diam. 10 mm.; aperture 11 mm. long, 5.5 wide 



(P/r.). 



S. Thome : stony slopes at 2500 ft. alt. and the coffee plan- 

 tations 500 ft. lower (Welwitsch) ; Monte Cafe (Greef et 

 Castro) ; almost the whole island, between 200 and 1400 

 meters alt. 



Achatina clavus PFR., Symbols iii, p. 20 (1846) ; Monogr. 

 ii, p. 260. REEVE, Conch. Icon, v, pi. 16, f. 75 (1849). 

 MORELET, Voy. Welwitsch, p. 76. Homorus clavus Girard r 

 Jornal de Sci. Math. Phys. e Nat., Acad. Real Sci. Lisboa, (2), 

 hi, p. 95 (1893). KOBELT, Conchyl. Cab. p. 97, pi. 26, f. 5, 6. 



According to Girard, this is the commonest Homorus on 

 S. Thome, reported from the shore up to 1400 meters. Like 

 H. barbiger, it presents several varieties of form and con- 

 vexity of the whorls, and the color varies from light yellow 

 to brown, the general tint being intensified on the last whorl. 



The apex is conic, acute, the early whorls being closely 

 sculptured with fine curved riblets. The later whorls are 

 densely striate, with slight traces of decussation. The striae 

 are stronger and curved below the suture. The aperture is 

 quite oblique. Fig. 11 represents Pfeiffer's type, after Reeve. 

 Figs. 9, 10 are drawn from a paler specimen measuring 32 

 mm. long, 9 wide. 



Pfeiffer in the Monographia iv, p. 608, has included an 

 Achatina inflecta Gld., from Liberia, in the Luders collec- 

 tion, as a synonym of clavus. Girard, with good reason, 

 states that confirmation of the continental occurrence of 

 H. clavus is still wanting. 



4. T. ARATISPIRA Pilsbry, n. sp. PL 56, figs. 16, 17. 



Shell olivaceous-yellow with the spire fading to whitish 

 above, rather thin but solid, glossy. Whorls 6!/2, the first 

 half whorl smooth, glossy, projecting and minute, the follow- 

 ing whorls flattened, slightly convex, all but the last two 

 closely, regularly costulate; the riblets gradually diminish- 



