274 Annals of the South African Musewm. 
Genus UNIO, Retz, 1788. 
(Dissert. Nov. Test. Genera, Lund. p. 16.) 
Type of Genus, U. pictorum (Lin.). 
The four species which follow are left in Unio, to which they 
were originally attributed, pending further investigation. I have 
Dr. Haas’ authority for stating that they do not really belong to 
that Genus, but that it is doubtful whether either of them can be 
placed in Cafferia. 
579. UNIo FISSIDENS, Bottger. [S.A.M.] 
1886 Unio (Hyridella) fissidens, Bttg., Ber. Senckenb. Naturf. Ges. 
Frankfurt, p. 27. pl. 2,f.6,7. Df. 
1910 = Bttg., Abh. Senckenb. Naturf. Ges. 
Frankfurt, xxxil. p. 463. N. 
Type in Senckenburg Mus. Frankfurt. 
Hab. BrivisH BECHUANALAND. Nosob-Hygap watercourse, east 
of Kebeum (subfossil, Nolte). Witkop (subfossil, Schultze ; Rogers). 
580. Unio HYGAPANUS, Béttger. 
1886 Unio (Hyridella) hygapanus, Bttg., Ber. Senckenb. Naturf. 
Ges. Frankfurt, p. 26. pl. 2, f. 5. DF. 
Type in Senckenberg Mus. Frankfurt. 
Hab. British BrecHuaNALAND. Nosob-Hygap watercourse, east 
of Kebeum (subfossil, Nolte). 
Described from a single left valve; possibly only a less highly 
sculptured form of fissidens. 
581. UNIo KUNENENSIS, Mousson. 
1887 Unio kwnenensis, Mouss., J. de C. xxxv. p. 300. pl. 12, f.10. DF’. 
1891 FF » Smith, A.M.N.H. viii. p. 319. N. 
1904 * » von Mts., Die Kalahari, p. 758. N. 
Type in Zurich Museum. 
Hab. OvamponaANnD. Kunene River (Schinz). 
BECHUANALAND. Okavango and Botletle District, and in the salt 
pans of the Makarrikarri brook (fossil, Passarge). 
“Nearly allied to U. hauttecoeuri, Bgt., and other species from 
the East African Lakes ”’ (von Martens). 
582. UNIO ZAMBESIENSIS, Preston. 
1905 Unio zambesiensis, Prest., Proc. Mal. Soc. vi. pp.300,f.1 ; 301. DF. 
Type in British Museum. 
Hab. Ruopesta. Victoria Falls (Morrell). 
