the Sonth-Aj'i'ican Sicii>);^}iiiiio. 2.jl 



placed at pro.sput ; but wliilc ho much uticertiiiiity exiitn 

 rcijjarilin^ tlic hahlts and anatomy of many of the animah, I 

 think it iiiadvisahlc to further complicate matters by a possibly 

 erroin'ous recLissitication. 



ItJ the following notes, every shell of wliich I have counted 

 the whorls and taken the measurements has been so dealt 

 with lyiuj; flat on its back, aperture upwards. The very 

 important moiisuremcnt which I call length of last whorl is 

 that taken from the extreme base of the aperture to the centre 

 of the suture immediately above it. 



I have usually taken as type the largest specimen available. 

 Nearly all Stonogyrinaj begin to reproduce before attaining 

 full size, though, as a general rule, the presence of eggs in 

 the ovary may be taken as proof that the shell is at least 

 two-thirds grown. Some species, however, certainly begin 

 to reproduce before their shells attain half the size of typically 

 large specimens. Whether these individuals would, in ordi- 

 nary course, continue growth to large dimensions, or whether 

 their growth at the time of reproduction is almost completed, 

 has not, I believe, yet been determined. 



In the present survey I have taken as my northern geogra- 

 phical limit the Tropic of Capricorn, thus excluding the genus 

 Sulixdina, which is a tropical rather than a South-African 

 form. 



With the exception of Enonyma unicornis, the types of all 

 the new species have been presented by Messrs. Ponsonby, 

 Farquhar, or myself to the British Museum. 



Heference List, with Notes. 



Family Achatinidae. 



Subfamily SrsyooTRiy^. 



Genus Euonyma, M. & P., 1906. 

 (Ann. & Mag. Nat. Hist, xviii. p. 310.) 



Proposed by Melvill and Ponsonby for the sinistral form 

 l^Bocochlis, and extended by Pilsbry to embrace the South- 

 African group of " rather large, f*lendor Stenogyroid snails" 

 which he consiilcrs to differ from Opens chiefly in their larger 

 size and getieral a.'*pect, and to be kept separate from Stcnu- 

 <7y;a solely by the diverse geographical distribution, Stenogyra 

 in the restricted sense comprising only tropical American 

 species. 



It rests with son)e future student of anatomv to decide 



17* 



