265 

 A COLLECTION OF MOLLUSCA FROM THE BELGIAN 



CONGO. 



By G. C. SPENCE. 



(Read before the Society, gth June, 1920). 



Through the courtesy of Mr. J. VV. Jackson the above Collection, 

 made during 1918 and 19 19 by our member, Mr. F. M. Dyke, has been 

 entrusted to me for investigation. The number of specimens is not 

 large, but they are mainly in fine condition. It soon became apparent 

 that there was a number of novelties and these were being worked up 

 when, most opportunely, Dr. Pilsbry's work on Congo Mollusca^ was 

 issued. It was then found that all these novelties were therein 

 described and figured. Mr. Dyke has made full and careful notes, 

 and the particulars given hereafter are from information kindly 

 supplied by him. 



Collections were made at the following places : — • 

 (i) Leverville, District du Kwango, at the junction of rivers Kwenge 

 and Kwilu. Approximate situation, 5°io'S ; i8°4o'E. 



(2) Tango, Dt. du Kwango, on right bank of Kwilu some 40 km. 

 north of Leverville. 4°4o'S ; t8°35'E. 



(3) Boteke, Dt. de I'Equateur, a small native village on R. Ruki. 

 o°i2'S; 18055'E. 



(4) EHzabetha, Dt. d'AruwJmi, on R. Congo opposite Basoko. 

 1^12' N; 23^40' E. 



(5) Iboro Island, a long narrov/ island (some 20 x i/ii km.) about 

 15/20 km. above EHzabetha and opposite Yalemba on right bank 

 of Congo. About i^S' N; 23*^55' E. 



(6) Alberta, nr. Bumba, Dt. de Bangalas. Bumba's position 2'^10'N ; 

 22*^30' E. 



Boteke "was the best by far for collecting ... the position is of 

 some interest ; near the Equator, there is an equable temperature and 

 well distributed rainfall throughout the year." 



" I have been very struck with the paucity of molluscs in palm 

 forests and have wondered whether the dryness of the soil had 

 anything to do with this. The palm is essentially a surface feeder 

 and one rarely finds real forest trees in quantity growing with the 

 palms. At all events, the shells taken in palm growing districts were 

 usually found under leaves, &c., in patches of undergrowth away from 

 the immediate neighbourhood of the palms {Elceis guineensis). I have 



I "A Review of the Land Molluscs of the Belgian Congo, chiefly based on the collection, 

 the Amer. Mus. Congo Expedition, 1909/15," in Bull. A.M.N.H., vol. xl, 1919. 



