MOLLUSCA FROM THE SOUTHERN SUDAN. 243 



Planorbis cosmius, Lines. 



Plajiorbis cosmius, 1884, Walter lunes, Bull. Soc. Malac. France, vol. i. p. 335. 



I took but a single specimen of this small form at Kanisa, which I sent to 

 M. Pallaiy, as I thought it might be the same as some examples from the 

 White Nile referred to by him in Bull. Inst. Egypt, p. 90, which he did not 

 name. He replied that it was conspecific and suggested my comparing it 

 with P. cosmias, Lines. It agreed with the description by Dr. Lines Bey, who 

 considers the species to be the Egyptian representative of P. spirorhis. I 

 therefore compared it with British specimens of that species, and found that 

 it comes nearest to the variety ecarinata, Jeffr.; it is, however, lower, and the 

 last whorl is wider. Jickeli * writes of a new species o^ Planorbis having very 

 narrow flat whorls which was found by Prof. Schweinfurth in the Bahr el- 

 Grliazal. This also may possibly be P. cosmius. 



Dr. Innes Bey had previously found other specimens near Ramleh. 



Subgenus Segmentina^ Fleming. 



Segmentina angusta, Jickeli. 



Four specimens were met with. Bahr el-Zarafa (one living), Hillet al- 

 Nuwer (one dead), Kanisa (two living). The largest has a diam. of 3*5 mm. 

 Jickeli states that this species is ver}'- rare ; he reports it from the White 

 Nile, Bahr el-Ghazal, and Abyssinia. Dr. Boettger received one example 

 only from the Bahr el-Ghazal. 



Segmentina kanisaeinsis, sp. nov. 



Five examples taken in marshy pools near the river at Kanisa. 

 A description by Mr. Preston is given in Appendix I., p. 265. 



Grenus Isidora, Ehrenherg. 



IsiDORA BROCCHii, Elirenh. 



Jsidora brocchii, Elireuberg, 1831, ' Symb. Phys.' No. 2. 



Phi/sa brocchii, Bourguignatj 1862, ' Pal^ontol. Alg.' p. 84, pi. 5. fig. 20. 



Two examples from Gebel En. The largest measures, alt. 7*5, diam. 

 4'75 mm. Bourguignat gives alt. 8-10, diam. 6-7 mm. 



This species is chiefly distinguished from /. truncata by its higher spire 

 and narrower body- whorl. 



It has been reported from Egypt, Algeria, and Syria.. 



* ' Fauna der Land- u. Siisswasser-Mollusken N.O.-Afrikas,' Nova Acta der K. Leop.- 

 Carol. Deutsch. Akad. d. Naturf. vol. ii. 1874, p. 217. 



