266 Bulletin American Museum of Natural History [Vol. LUI 
INCERT& SEDIS 
*Melania tanganyicensis E. A. Smith 
Melania tanganyicensis E. A. Smitu, 1880, Ann. Mag. Nat. Hist., (5) VI, p. 427; 
1881, Proc. Zool. Soc. London, p. 291, Pl. xxxtv, fig. 25. H. Crossz, 1881, Journ. de 
Conchyl., X XIX, p. 115. E. v. Martens, 1897, ‘Deutsch Ost Afr., IV, Beschalte 
Weichth.,’ p. 197. E. A. Smirxu, 1904, Proc. Malacol. Soc. London, VI, 2, p. 100. 
ANCEY, 1907, Bull. Scientif. France et Belgique, (5) IX, (1906), p. 250. 
Horea tanganikana BouRGuiIGNat, 1888, ‘Iconogr. Malacol. Tanganika,’ PI. 
XI, figs. 28 and 29; 1890, Ann. Sc. Nat. Zool., (7) X, p. 161, footnote, Pl. x1, figs. 28 
and 29. 
Lake Tanganyika (Thomson Coll.). Originally described without indication of a 
more definite locality. 
This species does not appear to belong to either Potadoma or Melanoides. In 
case it should prove sufficiently distinct, the generic or subgeneric name Horea Bour- 
guignat (1888, ‘Iconogr. Malacol. Tanganika,’ p. 28) might perhaps be retained for 
it.! 
PACHYMELANIA EH), A. Smith 
Claviger HALDEMAN, 1842, Silliman’s Am. Jl. Sci., XLII, p. 216. Monotype: 
Nerita aurita O. F. Miller. Not Claviger Preyssler, 1790. 
Vibex Gray, 1847, Proc. Zool. Soc. London, p. 153. Monotype: Nerita aurita 
O. F. Miller. Not Vibex Rafinesque, 1815, nor of Oken, 1815. 
Pachymelania E. A. Smrru, 1893, The Conchologist, II, p. 142. Substitute for 
Claviger Haldeman. Not Pachymelania White, 1895. 
Hemipirena RovERETO, 1899, Atti Soc. Ligustica Sc. Nat., X, p. 109. Substitute 
for Claviger Haldeman. . 
Clavigerina E. v. Martens, 1903, ‘Wiss. Ergebn. Deutsch. Tiefsee-Exp.,’ VII, 1, 
p. 14. Substitute for Claviger Haldeman. 
Itameta H. v. Tnerine, 1909, Journ. de Conchyl., LVII, p. 297. Substitute for 
Claviger Haldeman and Vibex Gray. 
The shell is solid, turrited, with sculpture of axial folds sometimes obsolete in the 
adult stage, and spiral threads, carine, or series of tubercles or nodules. Aperture 
small, the outer lip sigmoid, retracted above and at the base ; columella thickened. 
The operculum (Fig. 44) is narrow, with straight columellar margin, on which the 
nucleus is marginal near the base. Scar of attachment shaped like the operculum and 
occupying more than half its width. 
The radula resembles that of Melanoides. 
The genus Pachymelania is strictly West African, being found along 
the coast and on the islands of Upper and Lower Guinea, from Senegal 
to Angola. It prefers brackish water of rather high salinity and is often 
extremely abundant in the mangrove swamps and on the mud-flats within 
reach of the tide, in the lagoons and river estuaries, in company with 
certain species of Potamides. There appear to be only three distinct 
1Bourguignat’s Horea (type: Horea tanganikana Bourguignat = Melani } } i 
: na B gnat = Melania tanganyicensis BE. A. Smith 
has precedence over Horea FE. A. Smith, 1889, which is a synonym of Lechaptoisia Ancey. 
