6 ACHATINA, WEST AFRICA. 



in the Monographia Heliceorum. Adolf d'Ailly, in his Con- 

 tributions a la connaissance des Mollusques terrestres et d 'eau 

 douce de Kameroun, in Bihang till K. Svenska Vetenskaps- 

 Akad. Handlingar, xxii, Afd. iv, no. 2 (1896), has treated 

 the Achatinida occurring in Kamerun with the ability of a 

 master. Further southward, our knowledge of the species 

 of the Portuguese territory, Angola, etc., is very largely due 

 to the work of Arthur Morelet, in the Voyage du Dr. Fried- 

 erich Welwitsch dajis les Royaumes d 'Angola et de Ben- 

 guella, Mollusques terrestres et fluviatiles (1868). The 

 species of the vast Congo basin are still known by only a 

 few descriptions by Dupuis and Putzeys in the publications 

 of the Royal Malacological Society of Belgium. 



Key to West African Ackatina. 



I. Shell small (alt. less than 50 mm.), thin, ovate, the 

 diam. more than half the length. Whorls 6 to 6%. 

 a. Greenish-buff or greenish-brown with dark streaks ; 

 spire short. 



b. 45 x 24, apert. 26 mm. ; Damaraland. 



dammar ensis, no. 17. 



bb. 32x19 mm.; Angola. hortensia, no. 18. 



aa. Pale fulvous with zebra stripes, whorls 6, 18 x 

 12 mm. mollicella, no. 27. 



aaa. Broad chestnut stripes confluent at base, broken 

 or reduced on the spire; suture with brown mar- 

 gin ; 33 x 17 mm. sylvatica, no. 26. 

 II. Shell rather small, length 35 to 65 mm., narrow, the 

 diam. of shell and length of aperture much less than 

 half the length of the shell ; usually streaked or striped ; 

 whorls 71/2 to 9. Species 110. 21 to 25. 

 III. Shell ovate or oblong, the diam. half the length or a 

 little less; shell of moderate or large size. 



a. Shell granulate or spirally striate throughout; 

 spire long; aperture and columella pale. 



b. Thick; finely plicatulate and densely gran- 

 ulate throughout; 108-140x49-67, apert. 57- 

 75 mm. balteata, no. 29. 



