100 Beport of the Billiarzia Mission in Egypt, 1915 



Pallary records specimens from the canals at Alexandria, at 

 Samanoud and Cairo — "in a word, throughout Lower Egypt." 

 From our experience, however, it certainly appears to have a very 

 limited distribution as compared with BullimLS and other common 

 forms in the Delta. 



919 



Fig. 62. — Planorbis buissiji. (x 1.) 



In the Sudan, where intestinal schistosomiasis is fairly common, 

 this species has a wide distribution. Mrs. Longstaff has recorded 

 finds at the following places on the course of the White Nile : 

 north and south of Lake No; at Abba Island, Hillet Abbas, Gebel 

 En, Bahr-el-Zarafa, and Hillet-al-Nuwer. The Swedish Expedition 

 collected numerous young examples at Gebel Ahmad Aga. These 

 places are shown on the accompanyiiig map. 



Planorbis laurenti, Bourguignat, reported from Lake Timsah and 

 from marshes near Ismailia, appears to be the same as P. boissiji. 



P. hoissyi is the intermediate Host of Bilharzia mansoni in man 

 in Egypt. The Gercaria of Bilharzia mansoni is shonm in fig. 45. 

 It harbours also the developmental stages of a second species of 

 bilharzid tvorm believed to attain maturity in an aquatic bird. 



Planorbis (segmentina) angnsta, Jickeli, 1874. 

 A single shell of this species was given to us by Dr. Innes, from 



I 



Fig. G3. — Planorbis {scgvicntina) angvsUi. (x 3.) 



his collection made on the White Nile. We have found dead 

 specimens in our field work. It is recorded from the shore of 

 Lake Mariout, near Mex, Alexandria. 



