354 



CENTRAL AMERICA 



CHAP. 



The land operculates are but scanty. Tomocyclus and Amplii- 

 cyclotus are peculiar, and Schasicheila^ a form of Heliciiia^ occurs 

 elsewhere only in the Bahamas. Ceres (see Fig. 18, C, p. 21) and 

 Prose?79meZ?a, two remarkable forms of non-operculate Helicinidae 

 (compare the Chinese Heudeia)^ are quite peculiar. Pacliycliilus^ 

 one of the characteristic fresh-water genera, belongs to the S. 

 American (Melaniidae) type, not to the N. American (Pleuro- 

 ceridae). Among the fresh-water Pulmonata, the Aplecta are 

 remarkable for their great size and beauty. In the accompany- 

 ing table " Mexico " is to be taken as including the region from 

 the United States border up to and including the isthmus of 

 Tehuantepec, and "Central America" as the whole region south 

 of that point. 



Land Mollusca of Central America 



(3) The Colombian Sub-region includes Colombia, New 

 Grenada, Venezuela, Guiana, Ecuador, Peru, and Bolivia. It has 



