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96 Bulletin American Museum of Natural History [Vol. LIII 
regard to their correct naming in medical publications, we present a 
summary in table form (p. 95) of the known host relationships. A 
point of interest brought out by this table is that the mollusean host is 
not, as a rule, specific, but that even diffierent genera may be involved 
in the history of the same parasite. Of the genera listed, Blanfordia, 
Hemibia, and Bulimus (= Bithynia) belong in the family Amnicolide; 
Bulinus, Physopsis, Planorbis, and Segmentina in the Planorbide; and 
Lymnza in the Lymnzide. The specific identity of the snails referred 
to “‘Melania” lbertina by Japanese workers is still open to question, 
since they have apparently not yet been studied by a malacologist. 
The common Japanese Melania libertina belongs to the genus Semzsul- 
cospira. 
In tropical and South Africa, where blood flukes are by far the most 
important trematode parasites from a sanitary point of view, the 
Planorbide (Planorbis, Bulinus, and Physopsis) which chiefly act as 
intermediate hosts are, fortunately, but seldom abundant. Furthermore,. 
as these snails prefer stagnant to running water, their control, resulting 
in the eradication of bilharziosis, may be comparatively easy in densely 
populated regions.? Copper sulphate, where it may be used without 
danger, is very effective in clearing ditches of snails. In many cases, too, 
domestic ducks have been found of great value in keeping down the snail 
population of ponds in the neighborhood of human habitations. Wild 
ducks, on the other hand, contribute rather to the dispersal of dangerous 
fresh-water mollusks from pond to pond.’ 
‘See Milton, F. 1923. ‘Note on the molluscan hosts of the human schistosomes.’ Journ. Trop. 
Med. Hyg., XXVI, pp. 211-213. Although this paper is a praiseworthy attempt to elucidate molluscan 
nomenclature as applied to medical problems, it still contains a number of misleading statements. 
?Chandler, A. C. 1920. ‘Control of fluke diseases by destruction of the intermediate host.’ Journ. 
Bare. aa XX, pp. 193-208. 
aker, F. C. 1922. ‘Fluke infections and the destructi f the int i : 
Parasitology Vi oe tie 10n o e intermediate host.’ Journ. of 
4 awston, F, G. 1923. ‘Some practical means of dealing with the menace of fresh-wat il 
in Natal.’ South African Med. Rec., X XI, pp. 514-515. 3 ore ee 
‘Cawston, F G. 1920. ‘The value of domesticated ducks in preventing diseases.’ The Natal 
Poultry Journ. 
Fah birds a cause of the spread of Bilharzia infection.’ Journ. Trop. Med. Hyg., XXIV 
pp. 109-110. : 5; 
