1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 93 
hematobium and could be experimentally infected with the parasite. 
Furthermore, in Portuguese localities where the outbreaks occur in man, 
specimens of this snail were found infected with cercariz agreeing 
in every respect with those of S. hematobium. 
A second species of Schistosoma, S. mansoni Sambon, differs from the 
foregoing in the shape of the eggs, which bear a lateral instead of a 
terminal spine, and in the fact that the eggs are voided in the digestive 
tract and are eliminated with the feces instead of with the urine. The 
disease it produces is therefore usually designated as intestinal bilharziosis. 
S. mansoni occurs together with S. hematobium in many parts of Africa 
and was formerly thought to be but a form of that species. In the 
Belgian Congo it appears to be the most frequent agent of bilharziosis, 
being common in certain parts of the Katanga district and elsewhere 
outside of the rain forest belt. It is the only species of Schistosoma known 
from tropical America, where it was probably introduced from Africa. 
The life-cycle is similar to that of S. hematobium, but the intermediate 
hosts are species of Planorbis: P. boissyz Potiez and Michaud, in Egypt, 
according to Leiper; P. guadelupensis Sowerby, in Venezuela, according 
to Iturbe and Gonzalez’; P. olivaceus Spix and P. centrimetralis Ad. Lutz, 
in Brazil, according to Ad. Lutz; and P. antiguensis Gould, in the West 
Indies, according to 8. B. Jones. In Central Africa the intermediate 
host is but imperfectly known. Recent experiments by W. H. Dye? 
have shown that, in Nyasaland at least, a species of Planorbis related 
to P. sudanicus must be incriminated. In South Africa Annie Porter 
found that S. mansoni produces cercarie in at least three mollusks, 
namely Planorbis pferfferr Krauss, Physopsis africana Krauss, and Bult- 
nus tropicus Krauss.° 
Schistosoma japonicum (Katsurada) is an endemic blood fluke of the 
Orient (Japan, China, Philippine Islands, etc.), where it is most common 
in cats and dogs, but also frequently infects man. ‘The life-history is 
similar to that of S. mansoni. Miyairi and Suzuki,* in 1913, first succeeded 
1Schistosoma hematobium (Bilharz) originally included both forms. In 1864, Harley described the 
form with eggs havinga terminal spine as Distomum capenseand in 1907 Sambon named the form in which 
the egg has a lateral spine Schistosoma mansoni. If one wishes to adhere strictly to the rules of nomen- 
clature, S. mansoni is a synonym of S. hematobium, but we have followed the general usage in calling 
S. hematobium the form in which the egg has a terminal spine (Harley’s D. capense). ‘y 
2Iturbe, J. and Gonzalez, E. 1917. ‘Theintermediate host of Schistosomum mansoni in Venezuela.’ 
(Caracas), 10 pp., 2 Pls. 
Reported by J. B. Christopherson, 1923, Nature, CXII, p. 436. ; 
41921, Med. Journ. South Africa, XVI, pp. 75-76. See also Porter, Annie. 1922. ‘Some modern 
developments in animal parasitology.’ South African Jl. of Sci., XIX, pp. 64-94. 
5A comprehensive account of Schistosoma mansoni is given by Ad. Lutz. 1919. ‘O Schistosomum 
mansoni e Schistosomatose segundo observac6es feitas no Brazil.’ Mem. Inst. Osw. Cruz, XI, 1, pp. 
121-155, Pls. xxxvut-xtiu (English translation, pp. 109-140). Iturbe and Gonzalez’ experiments have 
been doubted by Faust (1918, Journ. of Parasitology, IV, p. 109). See alsoS. Kemp and F. H. Gravely. 
1919. ‘On the possible spread of schistosomiases in India.’ Indian Jl. Med. Research, VII, 1, pp. 251- 
264 
“61913, Tokio Med. Journ. (in Japanese); see 1914, Tropical Disease Bull., ITI, p. 289. 
