110 Transactions of the Royal Society of South Africa. 



In some cases, therefore, I have not given the earliest reference to a species, 

 when no figure was presented with it, but have given the original date of 

 its description, and a later reference, usually by the same author, to a 

 work in which both description and figure may be found. The letters 

 D, F, L, N, A, R, appended to references, denote respectively Description, 

 Figure of shell or slug. Locality, Note, Anatomy, and Radula. 



The rough map on p. Ill shows nearly every locality mentioned in 

 Lorenzo Marques ; the few in Mozambique are easily found in any atlas. 



Unless otherwise mentioned, the types of all species described by the 

 present author are in his collection. 



GASTROPODA. 



Family STREPTAXIDAE. 



The arrangement v/hich follows of this family is that adopted by Pilsbry 

 in his work on the Belgian Congo, 1919 (Bull. Amer. Mus. N. H. xl.). 



Subfamily STREPTAXINAE. 



Genus Gonaxis, Taylor, 1877. 



Gonaxis gwandaensis (Prest.), 1912. 



1912. Streptaxis gwandaensis Prest., A.M.N.H. ix, p. 69, f. 1. D.F. 

 Hab. L. Marques. Wanetsi River, Magude District (Bell Marley). 

 A very typical example of this rare species, only known hitherto from 

 its original locality in Southern Rhodesia. It is perfectly figured by Preston. 



Gonaxis kirki (Dhrn.), 1865. 



1865. Streptaxis kirki Dhrn., P.Z.S., p. 232. D. 



1905. ,, (Gonaxis) kirkii Dhrn., Kob., Conch. Cab., p. 8, pi. 42, 



f. 14-15. D.F. 



Hab. L. Marques. Mtisherra R. Valley (Cressy). 



A well-sculptured shell of moderate size, with extremely distorted axis. 

 It was described from Mumba I., Lake Nyasa, and is the first of several 

 species from Nyasaland to be noticed in the following pages. 



Gonaxis cressyi Conn., 1922. 



(Plate IV, fig. 1.) 



1922. Gonaxis cressyi Conn., A.M.N.H. x, p. 113. D. 

 Hab. L. Marques. Mtisherra R. Valley (type) ; Dondo ; Zangwe Basin 

 (Cressy). 



