236 MRS. JANE LONGSTAFF ON NON-MARINE 



The fourth collection was made by Dr. Otto le Roi, o£ Bonn, and described 

 by Dr. 0. B. Boettger and Dr. F. Haas in Proc. Make. Soc, Sept. 1913. 

 Twenty-four species are recorded ; as five of these occurred in the Bahr el- 

 Ghazal exclusively, and two in the Nile further north, we are only con- 

 cerned with seventeen. Of these one form, Limicolaria koenigi, is regarded 

 as a new species. 



Of course these collections have many species in common ; allowing for 

 this we have a total of forty-four in all. 



I obtained fifty -three species, as well as several varieties, on the White 

 Nile — thirty-four species of Gasteropoda, and nineteen of Lamellibranchiata. 

 Two are new, both Gasteropods, which occurred in the Bahr el-Gebel ; one 

 is a species of Streptaxis, > the other of Segmentina. In the Blue Nile, in 

 addition to several common molluscs, I found a new species of Nodularia. 

 Four species of Gasteropoda from the Bahr el-Gebel are too imperfect to 

 name. Six or seven other species appear to be new records for the White 

 Nile, viz. : — Ltmieolaria turriformis, v. Marts., L. smitJii, Preston, Limnaea 

 cailliaudi, Bourg., Isidora dybowskii, Fischer, Sph(erium teilhardi, Pallary, 

 Eupera letourneuxi, Bourg., and jDerhaps Yeronicella nilotica, Cock. It is not 

 clear whether the last-named species occurred on the White Nile previously 

 or not. The only record of the habitat of the holotype is " by the Nile 

 above Khartum.''^ By Nile is probably meant Bahr al-Abyad, and the 

 mollusc may well have been brought down from above by floating Sadd. 



I have in addition six or seven species which have been previously 

 recorded by earlier collectors, as well as thirty-three of the same species as 

 those in the four recent collections just quoted. These contain also twelve 

 species * which I did not meet with, making a grand total of sixty-five 

 species for the White Nile exclusive of the region to the west of Lake No 

 and south of Pejaf. Since authorities differ in opinion as to what should 

 be regarded as a species, any numerical statement must be regarded as 

 approximate only. 



On our voyages up the White Nile our fellow-passengers were most kind 

 in bringing me all the land-shells they found, and I must especially mention 

 Messrs. Backhouse, Gwynne, and Wallace. I am greatly indebted to 

 M. Pallary for naming specimens, and to Mr. E. A. Smith and Mr. Pobson 

 for their courtesy in affording me facilities for studying in the British Museum 

 (Nat. Hist.), and to Mr. Preston for valuable assistance in many ways. 



* These are Cleojjatra verreauxiana, Bourg. (Hjigg), Bithynia hoissieri^ Charp. (Hao-g}, 

 Lanistes ovum, Peters (Boettger), Hydrobia schioeinfurthi, Jickeli (Hagg), Planorbis fcbteli, 

 Jickeli (Pallary), Isidora sericina, Jickeli (Hiigg), Physa subopaca, Lam. (Pall.), Physopsis 

 sp. ? (Pall.), Succinea rngulosa, Morelet (Hagg), Limicolaria hordofana, Shutt. (Pall.), and 

 L. connectens, von Marts. (Boettger). I liave not counted Corbicula radiata, Parr, and 

 C. pusilla, Parr., as Pallary considers them merely immature forms. 



