468 Bulletin American Museum of Natural History [Vol. LIII 
studies the mollusks show more distinct faunal features in these highlands 
than any other group of animals, and are as peculiar as the vegetation. 
Of course, much of the distinctiveness of the molluscan fauna of moun- 
tainous regions is traceable to the formation of life zones with increasing 
altitude. , 
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Map 9. Orographic map of the Belgian Congo. 
genre under the direction of J. P. Chapin from map No. 2895, Geogr. Section, Brit. Gen. Staff, 
191 
But little is known at present of the ecological relations of Congo 
land mollusks with other organisms, and this is especially true of their 
feeding habits. ‘The Helicide, Achatinide, Zonitide, Urocyclide, Eni- 
de, Vaginulide, and land operculates are mostly. vegetarians, at least 
under normal conditions, but which species commonly attack living 
parts of plants we are unable to tell at present. It is certain that many of 
the Zonitide, Vaginulide, and Cyclophoride are merely scavengers, 
feeding upon decaying vegetable matter. Some of the large Achatinide, 
