358 On thè genus Poìnphólyx and its Allies, 
Tandon, aiidGray, wlio figure tliem as continnons. The great- 
est care and experience in observ'ation is reqnired to make reli- 
able notes on thè dentition. 
Limneria, H. & A. Adanis, belongs to thè Otinidce. 
Choanomjyhalus, Gerstfeldt, in thè present state of onr knowl- 
edge, cannot be positively placed ; bnt, if not a Trojgidina^ is 
closely allied to Pompholyx and Carinifex. 
Brondelia, Bonrg., froin its peculiar habitat, thè impressed 
radiations and rounded ribs of thè shell, as well as thè polished 
periostraca, ditfers, in niy opinion, snfficiently froin thè Ancyli 
to talee rank as a genus. Tire type, which is fi’oin Algerian 
forests, is figured by Binney, L. and F. W. Shells of N. A., 
Part II., p. 146. 
It is with great hesitation that I bave followed Menke and 
Troschel in separating thè Ancylidm as a faniily. The difier- 
ence in thè mode of coition seems to be chiefiy mechanical, 
caused by thè forni of thè shell. This patelloid shape is thè 
strongest character. 
On thè other band, thè form of thè foot, thè jaws, and den- 
tition agree closely with thè typical Limnmdae. At any rate, 
thè characters which separate them are far less valuable than 
those which distinguisi! thè Physidoi from thè LimnmidcB. 
The sub-family Camptocerinoì seems necessary, from thè 
very distinct characters which separate it from thè other 
groups. I feel justified in separating it provisionally until 
more is known. 
No one who has read thè acconnt of thè growth of Gund- 
lachia, by Dr. Stimpson (in Proc. B. S. N. H. 1863), can bave 
mneh doubt that thè genus Poeyia, Bourg., is a .young Gund- 
lachia, and there is much probability that Ancylics Cumin- 
gianus, of thè same author, from Tasmania, is an immature 
Latia. There is a possibility that thè lattei* genus (if thè posi- 
tion of thè eyes be correctly reported) may belong to thè group, 
characterized by a rudimentary operculum, of which Navicella 
