354 
On ihe genus Pompholyx and its AlUes, 
Family AlsCYLIDJE. Meuke, 1828. 
Faterai jaws present. Teeth resembling Ziìnncea. Shell 
patelliform, Hermaplirodite, but not capable of simultaneous 
reciprocai ìmpregnation, as are thè Limngeans, 
Group A. Shell siraple. 
Genus Acroloxus. Beck. 1837. 
Faterai plates not continuous with thè jaw. Mantle margin 
simple, thè pulmonary orifice closed by a small lobe. Tenta- 
cles subulate, stout, short. Genitalia on thè right side. Shell 
with tlie apex inclined to thè right. 
Type Acroloxus lacustris — Patella lacustris. Finn. 
Genus Ancylus. Geoffr. 1776. 
Faterai plates fused with thè jaw. Tentacles and mantle 
margin as in Acroloxus. Genitalia on thè left side. Apex in- 
clined to thè left. 
Type Aìicylus fluviatilis. Miill. 
Genus Brondélia. Bourg. 1862.* 
Soft parts nnknown. 
Shell shining, with an undulated margin, caused by rounded 
ribs which radiate from thè summit. Apex mammillated, 
slightly inclined to thè left. 
Type Brondélia Prouetiana = Ancylus Drouetianus. Bourg. 
f Genus Yalenciennius. Rousseau. 1842 (= Valencien- 
nensis Rouss. 1842, et Valenciennia, Bourg. 1855.) 
Shell large (125 mill. long, 72 broad, 77 high), thin, fragile. 
* This genus inhabits thè forests of Algiers, where two species are found on 
damp rocks away from thè water. 
f This remarkable genus is admitted bere in deference to thè opinions of 
MM. Deshayes and Bourguignat. It somewhat resembles Camptonyx, which 
Fischer has united with it, perhaps withont snfScient cause, under thè fourth 
generic name Valcncienntsia ! 
