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XLI] and who had never visited Africa, I found in his fæces numerous schistosomum eggs all bearing a lateral spine. Repeated examination of the urine proved negative, and the patient stated that he had never at any time suffered from hæmaturia. This case, together with the absence of endemic hæmaturia in the West Indies, led me to think that probably the lateral-spined ova indicated a distinct species of schistosomum, and I suggested this in a previous edition of this manual and elsewhere. Since then a considerable amount of information has accumulated in favour of my conjecture. A new species of schistosomum (S. japonicum), with what are practically spineless ova, and affecting the intestine only, has been discovered in Japan, and careful examinations for helminths in the Congo Free State (Broden) and in Porto Rico (Gunn and others) have shown the absence of urinary schistosomum disease and the frequency in these regions of a rectal schistosomum infection in which the ova of the parasite bear invariably a lateral spine. Finally, Sambon (Proceedings of the Zoological Society, March 9th, 1907), having had the opportunity of comparing specimens of the type characterized by lateral-spined ova with S.hœmatobium and other schistosomidæ, and taking into consideration its peculiar geographical distribution and distinct pathogeny, proposed that it should be ranked as a distinot species, and paid me the compliment of naming it S. mansoni in recognition of my suggestion. Since that time many cases of lateral-spined rectal bilharziosis have been reported from America by Flu (Surinam) and others. So far as I am aware, not a single case of terminal-spined bilharziosis of indigenous origin has been observed on that continent. The available material being very badly preserved, Sambon was unable to furnish the exact dimensions and the anatomical details of the new species, which closely resembles S. hœmatobium in general appearance and structure.*