1889. ] SO-CALLED PHYS OF AUSTRALIA. 137 
relationship between these groups of the South Pacific, which is 
already indicated by the distribution of Rhytida, Janella, and 
Placostylus. 
The object of this paper is to show that these so-called ‘ Physe,’ 
the sole claim of which to the title is that they are sinistral fresh- 
water-shells, are not Physe at all, buta group of sinistral Limneide, 
characteristic of the geographical area above indicated, and also of 
another part of the world, where their presence is of extreme interest. 
This view rests primarily upon an examination of the radula of 
some of the species concerned. 
As is well known, the radulee of the Physidee and the Limneide 
are essentially different, and tend to remove Physa much further 
away from Limnea than are either Planorbis or Ancylus. Fischer 
describes them as follows* :— 
Puysip. LIMN2ID&. 
Radula composed of teeth ob- Teeth of the radula in hori- 
liquely arranged ; central tooth zontal rows, bi- or tricuspid [cen- 
multicuspid; laterals and mar- tral tooth bi- or tricuspid, never 
ginals pectinate or serriform, and multicuspid]; marginal teeth 
provided with a special narrow _ serriform’*. 
appendage on the upper and ex- 
terior edge. 
In the ‘ Journal of Conchology,’ v. 1887, pp. 241-243, I described, 
under the name of Limnea physopsis, a new species of these Aus- 
tralian ‘ Physe.’ The reasons given for believing the species to be 
Limnezidan and not Physidan were based on (1) a consideration of 
the radula, and (2) the general facies of the shell. It was suggested, 
purely on grounds of general similarity of shell, that two other 
Australian species of ‘ Physa,’ viz. P. hainesii, Tryon (=Jatilabiata, 
Sowb.), and P. newcombi, Ad. and Ang., were also Limneide. 
Since that date several other species of this group of ‘ Physa’ 
have been examined, and with similar results. It may at once be 
asserted that, in spite of the 52 or 54 species enumerated, Physa has 
yet to establish its claim to be an inhabitant of Australia. Every 
species as yet, which has been examined anatomically, turns out not 
to belong to that genus; and I am strongly of opinion that further 
investigation of the animals of the species as yet known only by the 
shells will afford more evidence of a similar kind. 
The note of suspicion has already been sounded more than once 
with regard to these Australian Physe. Mr. R. M. Johnston has 
noticed a ‘‘ peculiar arrangement ” of the lingual teeth in P. tas- 
manica, the mediais of which are 2-cuspid, the laterals 4-, -, and 6- 
cuspid, the extreme ones having a resemblance to the closed digits 
of the hand’. 
? Manuel de Conchyliologie, pp. 503, 510. 
* It may be remarked that this description is inadequate, so far as Ancylus 
proper is concerned. 
* Proc. Roy. Soc. Tasmania, 1878, pp. 19-29: he uses the term laterals to 
include marginals as well, 
