MANUAL OF CONCHOLOGY. 



Family ACHATINIDJ3. 



Holopod, sigmurethrous snails with the central tooth of the 

 radula very narrow (with few exceptions), its cusp small or 

 absent, the side teeth tricuspid or bicuspid. Jaw generally 

 striated. Genitalia with no accessory organs. Kidney two or 

 three times the length of the pericardium. Pulmonary vein 

 without large branches. S'hell ovate, turrited or cylindric, 

 well developed and capable of containing the entire soft parts ; 

 the columella frequently truncated below. 



Distribution, tropical and subtropical regions throughout 

 the world. 



These snails differ from Bulimulicke by the long kidney, 

 from Acwuida by the very diverse venation of the lung and 

 the different dentition, and from the multiform group Heli- 

 cidce chiefly by the narrow central tooth of the radula and 

 the structure of the shell. Up to this time no Heliciform or 

 slug-like Achatinidce have been made known, but such types 

 probably exist in so large and varied a family. 



While widely distributed in the tropics, most of the genera 

 are confined to Africa and middle America. In tropical 

 Africa the number and variety of species is very great, and 

 they occupy that region almost to the exclusion of other groups 

 of Holopod snails, excepting the carnivorous Streptaxida. 

 The African Achatinidce fall into three groups which may be 

 rated as subfamilies, although the absence of full anatomical 

 data at the present time renders any classification provisional. 



I. Subfamily ACHATININ.E. Mostly capacious shells, ovate 

 or rarely subcylindric, usually decorated with zigzag 



(vii) 



