136 REV. A. H. COOKE ON THE [ Mar. 19, 
1. On the Generic Position of the so-called Physe of Aus- 
tralia. By the Rev. A. H. Cooxz, M.A., F.Z.S. 
[Received February 25, 1889.] 
The freshwater Mollusca of Australia, regarded as a whole, present 
only one feature which can be considered at all remarkable, namely 
the extraordinary development of the genus Physa. In a valuable 
paper “On the Freshwater Shells of Australia” *, Mr. E. A. Smith 
enumerates no less than 52 species of this genus. It is true he 
admits that some of these are undoubtedly synonymous with others? ; 
but even if we were bold enough to reduce the number by half, 26 
would still remain a large proportion. This is especially evident when 
we recollect that only eight or nine species of Australian Limnea 
are known, and only about seven of Planorbis. Professor Tate and 
Mr. Brazier, in their ‘Check-list of the Freshwater Shells of 
Australia ’*, enumerate 54 species of Physa*, “ more than half [the 
number | for the whole world.” 
These Australian Phys present, as a group, certain well-marked 
characteristics. They are, as a rule, remarkably large, thick shells, 
sometimes gibbous, sometimes much acuminated, sometimes sur- 
rounded with sharp ridges or keels. The columellar fold is 
generally strong, and in many cases there is present a stout epi- 
dermis. 
It does not appear that the animal of many of these species has 
been examined in order to see whether they had anything in com- 
mon with Physa besides the possession of a sinistral shell. One 
would have thought that the presence or absence of the tongued 
mantle, reflected over the shell, would have been noticed whenever 
the animal had been examined. 
This group of Physa is not peculiar to Australia, though it finds 
its most extensive development there. Shells of exactly the same 
facies occur in New Caledonia’ (14 species), Tasmania® (12 species), 
New Zealand” (8 species), Tonga Islands® (2 species), Viti Islands® 
(2 species), New Guinea’ (3 species). This fact confirms the close 
* Journ. Linn. Soe., Zool. xvi. 1883, pp. 255-317. 
* I have noted the following as probable:—proteus, Sowb.,=pyramidata, 
Sowb., +dispar, Sowb., +-pectorosa, Conr., +-breviculmen, Sm., +-badia, Ad. and 
Ang., +-concinna, Ad. and Ang., +¢exturata, Sowb. : gibbosa, Gld.=producta, 
Sm., +deddomei, N. and T., +fusiformis, N. and T.: reevei, Ad. and Ang.,=ca- 
rinata, H. Ad., +-obesa, H. Ad., +truncata, H. Ad., +bonus henricus, Ad. and 
Ang., +cumingii, H. Ad. 
* Proe. Linn. Soc. N. 8. Wales, vi. 1882, pp. 552-569. 
* Including Tasmanian species. 
° Various papers in the ‘Journal de Conchyliologie.’ 
° R. M. Johnston, Proc. Roy. Soc. Tasm. 1878, pp. 19-29. 
* Tenison-Woods, Proc. Linn. Soc. N. 8. Wales, iii. 1879, p. 159. 
® Mousson, Journ. de Conch. 3rd ser. xi. 1871, pp. 17, 18. 
® Mousson, Journ. de Conch. 3rd ser. x. 1870, pp. 130, 131. 
ao aaeparcns ee Ann. Mus. Gen. xix. 1883 (two species common to Aus- 
tralia). 
