150 HOMORUS, WEST AFRICA. 



28. H. INVOLUTUS (Gould). PI. 59, figs. 70, 71. 



Shell turrited, elongate, the apex mamillate; imperf orate, 

 brownish ; whorls 12, lightly striate, the upper four subequal, 

 the last whorl carinated; suture impressed, very minutely 

 crenulated. Aperture ovate, a sixth the length of the spire ; 

 columella arcuate, involute, forming a tube. Length 1.1, 

 width .25 inch. (Gld.) . 



West Africa: Cameroons at Bonge and Itoki (d'Ailly) ; 

 Cape Palmas, Liberia; on the banks of the Nun river (Fraser, 

 type loc. of A. fraseri) ; Sierra Leone at Freetown (Wel- 

 witsch) ; Togoland at Bismarckburg (Buettner). 



A slender, club-shaped shell, brown with irregularly-spaced 

 narrow darker streaks, the apex obtuse, rounded, rather large, 

 several whorls following not increasing in diameter. The 

 first whorl is smooth; the second has sharp, narrow, short 

 and widely spaced folds below the suture. On the third 

 whorl these folds are somewhat reduced. The whole pro- 

 toconch consists of nearly 3 l / 2 whorls. At the beginning 

 of the post-embryonic growth the surface becomes somewhat 

 dull, contrasting with the glossy protoconch, and at the suture 

 it is rather finely crenulate or puckered (pi. 59, fig. 70). 



Achatina involuta OLD., Proc. Bost. Soc. N. H., i, 1843, 

 p. 158. REEVE, C. Icon, v, pi. 17, f. 88. PFR., Monogr. iii, 

 p. 500; Conchyl. Cab. p. 343, pi. 37, f. 21, 22.Pseudo- 

 glessula involuta d'AiLLY, Bihang, p. 109. Achatina fraseri 

 PFR., Symbols? iii, p. 90 (1846) ; Monogr. ii, p. 263 

 PHILIPPI, Abbild. ii, p. 216, pi. 1, f. 6. REEVE, C. Icon, v, 

 pi. 16, f. 71. Subulina involuta MARTS. Mittheil. aus d. d. 

 Schutzgeb., vi, Heft, 3 (1893). 



Gould's description is given above. Adolf d'Ailly has 

 more fully described this species thus : ' ' Shell turrited-subu- 

 late, the apex cylindrical, rather obtuse, subpapillar; irregu- 

 larly striate, polished, whitish-greenish, here and there 

 streaked with darker, under a corneous-brown cuticle, usu- 

 ally worn off of the apertural side; under the lens hardly 

 visibly striate spirally and very densely. Spire-subconcave 

 towards the apex, the rest subcylindric, whorls 13, the first 

 and second subglobose, smooth, the suture regularly and dis- 



