1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo A473 
as their shell only affords protection against their weaker or less astute 
enemies.’’! , 
Among the amphibians, frogs and toads in Europe are said to 
devour considerable quantities of snails and slugs, so that they may 
conveniently be employed to clear gardens of such pests.2 Terrestrial 
mollusks were found by Kirkland? to constitute one per cent of the total 
contents of 149 stomachs of the American toad, Bufo americanus Hol- 
brook, both slugs and snails being taken. The amphibians of tropical 
Africa do not appear to be very efficient mollusk-hunters, as may be seen 
from the data contained in the subjoined table, based upon Mr. G. K. 
Noble’s dissections of a considerable number of frogs and toads collected 
in the Congo by Lang and Chapin. More than 550 stomachs belonging 
to some 45 species were examined, but mollusks were only recognized in a 
few cases, namely in certain species of Bufo, Rana, Leptopelis, and 
Arthroleptis. 
Number of 
Stomachs Total Number 
with Number of of 
Recognizable. | Animals | Mollusks 
Food Eaten 
Bufo regularis Reuss | 31 982 4 
‘“  polycercus Werner 53 aoa * 1 
Arthroleptis variabilis Matschie 17 425 5) 
Rana occipitalis Giinther 25 65 2 
‘‘ albolabris Hallowell 19 48 3 
‘“ mascareniensis Duméril and Bibron 24 50 Za 
‘“ -ornatissima Bocage 14 38 3 
‘“ christyt Boulenger 6 11 i 
“ oxyrhynchus A. Smith ohne 11 2 
Leptopelis aubryi (A. Duméril) | 25 36 a 
It would appear from these figures that mollusks are only a very 
secondary item in the diet of Congo amphibians. This is, we believe, to 
be attributed to the poverty of the land snail and slug fauna. The abun- 
dant insects offer a supply of food so readily accessible at all times that 
vA W. Taylor. 1894-1900. ‘Monograph Land Freshw. Moll. Brit. Isl., Struct. Gen. Vol.,’ (Leeds) 
416 
2Noél, P. 1891. ‘Destruction des limacons par le crapaud et la grenouille.’ Rev. Sc. Nat. Ouest, 
I, pp. 261-262. 
31904, U. S. Dept. Agric. Farmers’ Bull. No. 196, p. 8. 
4See also Noble, G. K. 1924. ‘Contributions to Hate herpetology of the Belgian Congo based on 
the collection of the American Museum Congo Expedition, 1909-1915. Part III.’ Bull. American Mus. 
Nat. Hist., N. Y., XLIX, pp. 147-347, Pls. xx1I—XLi. 
