10 ACHATINA, WEST AFRICA. 



narrow columella and smallness of the notch at its base are 

 prominent features. The acutely conic spire, small apex 

 and thin lip distinguish A. achatina from marginata. The 

 young shells are often more boldly marked than the adults, 

 on a lighter yellow ground. 



The egg 25 x 17 mm. attributed to this species by von 

 Martens ( Sitzungsber. Ges. naturforsch. Freunde, 1891, p. 

 33) must belong to the large form of A. marginata. A large 

 egg-capsule is always associated with a dome-like summit in 

 the shell, which A. achatina does not have. Its egg will be 

 found to be comparatively small, probably less than half the 

 dimensions given above. 



Mr. Ancey states that "several forms have been con- 

 founded under this name (variegata), which are worthy of 

 distinction; one of them, from Assinie, always smaller in 

 size, has been named by me A. chaperi" (Bull. Soc. Malac. 

 de France, v, 1888, p. 70, footnote 4). I have been unable 

 to find any further description of this form. 



la. Var. MONOCHROMATICA, n. v. PI. 32, fig. 3. 



Shell somewhat smaller, white under the smooth and glossy 

 olive-yellow cuticle, which is uniform except for some faintly 

 darker streaks marking growth-stages, and a faint peripheral 

 belt. Suture distinctly margined. Aperture smaller than 

 in achatina, colored the same. Length 120, diam. 65, aper- 

 ture 66 mm. 



West Africa: Angola (A. N. S. coll.). 



A. variegata Roissy, RVE., C. Icon., v, pi. 5, f. 3c. DESH., 

 in Fer. ? Hist, pi. 124, f. 3, 4. 



It is usually smaller than the type, Reeve's figure measur- 

 ing about 96 mm. long. This shell meets the requirements 

 of Bruguiere's Bulimus fulvus better than the East African 

 forms which authors have associated with that name. 



2. A. BUCHNERI Martens. PL 6, fig. 11, 12. 



Shell subturrite oblong, obsoletely decussate; buff, painted 

 \virli rather wide black-brown streaks, generally lightning- 

 zigzag and narrow above. Whorls 7, nearly fiat, the suture 



