315 



1925. A freshwater snail, Physa zionis, living under unusual conditions. 



Proc. Acad. Nat. Sci. Phila. 77: 325-328. PL 11. 

 Pilsbry, H. A., and J. Beqtjaert. 



1927. The aquatic molluscs of the Belgian Congo, with a geographical 



and ecological account of Congo malacology. Bull. Amer. Mus. Nat. 



Hist. 53: 69-602. PL 10-77, 15 maps, 93 text fig. 



SOWERBY. G. B. 



1822. The genera of recent and fossil shells, Limnea, 4 p. London: G. B. 

 Sowerby. 



SOWERBY, G. B. 



1873. Conchologia Iconica, Physa. London: L. Reeve and Co. 

 Suter, H. 



1913. Manual of New Zealand Mollusca. xxiii + 1120 p. 72 pi. Welling- 

 ton: John Mackay. 

 Turton, William. 



1807. British fauna. 230 + viii p. London: J. Evens. 



