Notes on South African Mollusca. 125 



of the family ever reached South America. Only the Bulimiform 

 genera, Strophocheilits (including Boms) and Gonyostomus, are 

 found in that region, and Plate has emphasized the very primitive 

 character of these snails.* The researches of Semper, | von IheringJ, 

 Plate,;; and Pilsbry || have shown that, besides retaining an elongate 

 shell, these South American genera have a very simple kidney with 

 no ureter, a radula in which the ectocones are usually still present 

 on the marginal teeth, and a free oviduct which is swollen or pro- 

 vided with an appendiculurn at its junction with the duct of the 

 sperrnatheca. 



But although these snails retain many primitive characters, they 

 have undergone a considerable development under the favourable 

 climatic conditions of Brazil. In some species the jaw has developed 

 stout ribs. Many of the forms attain a great size, and have very big 

 eggs. A large number of species have arisen, and they have spread 

 over the greater part of South America, though they are still most 

 abundant to the east of the Andes. To this subfamily Pilsbry has 

 given the name of StropJiocheilinaa. 



The subfamily which inhabits Australia and some of the neigh- 

 bouring islands contains far fewer species ; but so diverse are these 

 that they are assigned to at least twice as many genera as the South 

 American forms. Probably the group was once much commoner in 

 the Australian region than it is at the present day. 



The south of Australia is nearly as far from the centre of 

 evolution as is Brazil, and, with the exception of Anoglypta launces- 

 tonensis, all the species from this region are more or less Bulimiform. 

 Further north, however, we find the greatly depressed genus 

 Pedinogyra in Queensland and New South Wales ; while in the 

 most northerly species of HcdlcijcUa, instead of the spire having 

 been flattened, the entire shell has become reduced, so that it can 

 no longer contain the animal. The teeth of the radula have almost 

 entirely lost their secondary cusps in this group, ^ and a primary 



* Sitz.-Ber. Ges. naturf. Freunde, Berlin, 1896, p. 149. 



t Reis. im Archip. Philippin., 1874, iii. p. 150. PI. XIV, f. 10, PI. XVI, f. 25, 

 PI. XVII, f. 1, PI. F (1894), f 5. 



I Zeitsch. f. Wissensch. Zoologie, 1884, xli. p. 270. PI. XVII, f. G, and Bull. 

 Scientifique, 1891, ii. p. 213. PI. V, f. 11. 



Op. cit. 



|| Man. Conch., 1895, x. p. 1, and 1902, xiv. pp. iv-viii. PI. XLIX, f. 8, 

 PI. LI, f. 10, PI. LII, f. 26, 27, PI. LIII, f. 35, PI. LIV, f. 37, PI. LVII, f. 59, 

 65-68. 



H The ectocones, however, can still be distinguished in the marginal teeth of some 

 specimens of Anoglypta 



