ACHATINA, WEST AFRICA. 5 



A. achatina, A. purpurea and A. zebra groups. I propose 

 to restrict the name to species of the bicarinata type, that 

 being the first species of Albers' list. 



Bourguignat, in 1889, made an ineffective attempt to dis- 

 member Achatina. He denned the following groups: 



1. Tripachatina for A. vignoniana Morel. This group is 

 a synonym or section of Limicolaria. See vol. xvi, p. 254, 

 no. 10. 



2. Parachatina for A. thomsoni Sm., dohrniana Pfr. and 

 welwitschi Morel., species characterized by the want of colu- 

 mellar truncation, which is replaced by a tuberculiform 

 eminence. These species belong, by their apical characters, 

 to Achatina s. sir. The columellar structure varies widely 

 and is of only minor systematic value. In many species of 

 diverse groups of Achatina the amount of columellar trun- 

 cation is reduced by the tapering of the lower end of the 

 columella. A similar process has resulted in the condition 

 reached by Burtoa. 



3. Serp&a for small globose species with the shell thin 

 and transparent. A. hortemic? Mor., dammarensis Pfr., 

 knori Jonas, varicosa Pfr. (the young only), obesa Pfr., 

 pintoi Bgt. This list includes species of several of the most 

 diverse groups of Achatina. 



4. Achatina including all the other large species of West, 

 South and East Africa. A heterogeneous group. 



4a. Pintoa for slender, elongate species, such as A. pfeif- 

 feri Dkr. 



WEST AFRICAN SPECIES. 



The West African Achatinae are usually more richly col- 

 ored than the East African, and they are more diversified 

 in form, size and coloration. No species are yet known to be 

 common to the West and the Lake region or east coast. 



LITERATURE OF WEST AFRICAN SPECIES. The larger Acha- 

 tinae of the coastal region from Sierra Leone to Gabun were 

 among the first known, and were figured and described in 

 the works of Seba, Linnaeus, Chemnitz, and other early 

 authors. Many of them are beautifully illustrated in Reeve's 

 Conchologia Iconica, and have been well described by Pfeiffer 



