SCHISTOSOMA MANSONI 277 



consider them as indicative that the miracidium has developed into 

 a sporocyst, but Looss considers them to be degeneration products. 



The Bilharzia mission, under R. T. Leiper, sent to Egypt by the 

 War Office early in 1915, reports that cercariae of bilharzia type were 

 recognized in four of the commonest fresh-water molluscs around 

 Cairo. 



With material obtained from naturally infected Planorbis boissyi 

 acute bilharziosis was experimentally produced in rats, mice, and 

 monkeys. Infection takes place experimentally through the skin and 

 also through the mucous membrane of the mouth and oesophagus. 

 The miracidium, after entering the mollusc, develops into a sporocyst. 

 This gives rise not to rediae, but to secondary sporocysts, which, in 



Schistosoma haematobium, Bilharz, 1852. 



"Male, four or five large testes. Gut forks unite late, so that the 

 single gut stem is short. Female, ovary in posterior half of body. 

 Uterus very long, voluminous, with many terminal-spined eggs, some 

 lying in pairs. Vitellaria in posterior fourth of body. Cercariae in 

 Bull Inns contortns and Bullinus dybowski (syn. : Physa alexandrina) in 

 Egypt. 



Schistosoma mansoni, Sambon, 1907. 



Male, eight small testes. Gut forks unite early, so that the single 

 gut stem is very long. Females, ovary in anterior half of body. Uterus 

 very short ; usually only one lateral-spined egg at a time /// utero. 

 Vitellaria occupy posterior two-thirds of body. Cercariae in Planorbis 

 boissvi in Egypt. 



The above morphological descriptions are founded on worms of 

 each species, derived from experimentally infected mice (Leiper, R. T., 

 Brit. Med. ^onrn., March 18, 1916, p. 411). 



To Binder : face p. 276 



>yn. : 5T cattot, Blanchard, 1905. 



Male. Eight to 19 mm., but extreme limits are 5 to 22-5 mm. Con- 

 sists of a short fore-body, separated by the ventral sucker from the 

 hind-body. The ventral sucker is stalked and somewhat larger than 



