Mr. E. A. Smith on African Mollusca. 317 



Neuqucn, Patagonia*. Mr. ]\Iawson's discovery of tlie 

 Pterodactyl seems to be the first of the kind in the Southern 

 Hcmispliere ; tliat of the Plcsiosaur adds another important 

 locality to the known distribution of an order that has an 

 equally wide geograj)liical range in both Hemispiieres. 



XLII. — Notes on African Mollusca. By Edgar A. Smith. 



I. UNiomDJE OF South Africa. 



At present nine species of this family have been described from 

 the southern extremity of the African continent, namely seven 

 so-called species of the genus Unio and two species of Mutela. 

 Five, if not six, of the forms of Unio really belong, I believe, 

 to one and the same species. They have been separated on 

 account of slight differences of form and sculpture, which, 

 when a large series of specimens is examined, prove to be 

 very unreliable and inconstant. Intermediate forms both in 

 respect of outline and sculpture are met with, showing that 

 the separation of these various forms cannot be maintained. 

 The synonymy is as follows : — 



1. Unio caffer^ Krauss. 



1848. Unio coffer, Ki-au?s, Siidafr. Moll. p. 18, pi. i. fig. 14. 



1856. Unio cc^er, Kiister, Conch.-Cab. p. 143, pi. xlii. figs. 2, 3. 



18G0. Unio caffer, Sowerby, Couch. Icon. pi. xli. fig. 226. 



1850. Unio Verreauxiamis, Lea, Proc. Acad. Nat. Sci. Philad. vol. viii. 



p. 94. 

 1858. Unio Verreauxianus, id. Jourii. Acad. Nat. Sci. Philad. vol. iii. 



p. 301, pi, xrvii. fig. 16. 

 1868. Uiio Verreauxianus, Sowerby, I. c. pi. Ixix. fig. 352. 

 1850. Unio africanus, Lea, Proc. Acad. Nat. Sci. Philad. vol. viii. 



p. 94. 

 1858. Uiiio africanus, id. Journal, vol. iii. p. 300, pi. xxvii. fig. 15. 



1865. Unio africanus, Sowerby, I. c. pi. xxii. fig. 100 (wrong locality 

 given). 



1864. Unio natalensis, Lea, Proc. Ac. N. Sci. Phil. vol. xxii. p. 113. 



1866. Unio yiafalensis, id. Jom-nal, vol. vi. p. 59, pi. xx. tig. 57. 

 1868. Unio natalensis, Sowerby, I. c. pi. Ixxi. fig. 362. 



1885. Unio vaalensis, Chaper, Bidl. Soc. Zool. France, vol. x. p 480, 

 pi, xi. figs. 1-3. 



Hah. Eivers of Natal and Cape Colony. 



This species has the surface ornamented with concentric 



* F. P. Moreno, " Le Musee de La Plata " (in ' Revista de Museo de 

 la Plata,' vol. i., 1890), p. 18. 



