1889. ] SO-CALLED PHYS OF AUSTRALIA. 141 
p- 139) with the same teeth of these Bulini will make this clear. 
In Planorbis the central tooth is broad-based, bicuspid, while the 
laterals are tricuspid; in Limnea the central tooth is long and 
narrow, unicuspid, while the laterals are bicuspid. A Bulinus, there- 
fore, is not so much a sinistral Limnea asa spiral Planorbis. Further 
research, as the animals of more species are investigated, may, per- 
haps, bring out some points of difference leading to division into 
subgenera of the Australian and Austro-Polynesian species. It is 
pessible that the somewhat wing-shaped form of the central tooth 
in some cases (see figs. 2, 3,5, 7, 8, p. 139), as compared with its 
more regularly square shape in others (see figs. 1 and 4), may indi- 
cate a basis of subdivision; but at present there does not seem 
sufficient material to work upon. 
Finally, as regards nomenclature. 
Adanson, in 1757, described and figured* under the name of 
Le Bulin or Bulinus a small sinistral freshwater shell from Senegal, 
length 12 lines, breadth 3 line. The shell is evidently not adult, 
but the description and magnified drawing of the animal, which 
shows none of the produced mantle-lobes of a true Physa (indeed, 
Adanson fortunately remarks, “le manteau tapisse tout l’intérieur 
de la coquille sans sortir au-deli des bords de son ouverture’’), are 
sufficient to enable us to recognize it as belonging to the genus now 
under investigation. Fischer, therefore, is quite right im adopting 
Bulinus as the generic name’. 
Tsidora (Ehrenb. 1831) is a synonym, see Jickeli, loc. supr. cit. 
Fischer, in his ‘ Manuel,’ goes on to enumerate five subgenera, 
viz. Pyrgophysa, Plesiophysa, Ameria, Glyptophysa, and Physopsis. 
Pyrgophysa was proposed by Crosse* for Ph. mariei, Crosse, 
from Nossi-Bé, on the ground of its turreted spire. But this sub- 
genus is of little value, as the Australian species present every 
variety of stich formation. Crosse’s description of the shell (“ haud 
nitens, vestimento opaco induta”’) makes it plain that it belongs to 
this genus. 
Plesiophysa (Fischer, 1883) includes the remarkable Ph. striata, 
d’Orb., from Guadeloupe. This must be the ‘ Physa sp.’ from Point 
4 Pitre*, the radula of which is described by Bland and Binney’ 
as follows :—“ Central tooth 5-cusped, central of these the largest ; 
laterals 4-cusped, one inner, large, stout ; marginals a reproduction 
of the laterals.’” This description at once removes the species from 
1 Sénégal, pp. 5-7, pl. fig. G. ii. 
2 Yet he remarks: ‘“‘Etymologie inconnu.” Adanson, however, J. ¢., seems 
to make it fairly clear when he says:——“ Cette dénomination m’a paru lui con- 
venir, parce que l’animal pendant sa vie nage presque continuellement a fleur 
d'eau, et qu’aprés sa mort la coquille flotte comme une petite bulle d’air trans- 
parente.” 
ry Journ. de Conchyl. 3° sér. xix. 1879, pp. 208-209 ; xx. 1880, pp. 141-142, 
pl. iv. fig. 5. 
* Mazé (Journ. de Conchyl. 3° sér. xxiii. 1883, pp. 30-31) records Plesiophysa 
striata from Point 4 Pitre. 
5 “ Note on a curious form of lingual dentition in Physa,” Ann. Lye. N. 0 
N. York, x. 1873, pp. 255-257, pl. xi. figs. 2, 3. 
