."..'4 On ihc genua Pompholyx and its Alios, 



Family ANCYLIDJE. Menke. 1828. 



Lateral jaws present Teeth resembling LimncBa. Shell 

 patelliform. Hermaphrodite, but not capable of simultaneous 

 reciprocal impregnation, as arc the Limnseans. 



Group A. Shell simple. 



Genus Acrploxus. Beck. 1S37. 



Lateral plates not continuous with the jaw. Mantle margin 

 simple, the pulmonary orifice closed by a small lobe. Tenta- 

 cle- subulate, stout, short. Genitalia on the right side. Shell 

 with the apex inclined to the right. 



Type AcrcloxvtA laewt/ris = Patella lacustrie. Linn. 



Genus Anoylut* Geoffr. 1770. 



Lateral plates fused with the jaw. Tentacles and mantle 

 margin as in Acroloxit*. Genitalia on the left side. Apex in- 

 clined to the left. 



Type AncijJ us jfuviatilis. Miill. 



(imus Urn/, (!,!!<(. Bourg. L862.* 



Sofl parts unknown. 



Shell Bhining, with an undulated margin, caused by rounded 



rib- which radiate from the summit. Apex mainiuillate<l. 

 slightly inclined to the left. 



Type Brondt lia Drouetiana Aneylus Drouetianvs.l&oxirst, 



+ Genus Vdlenciennius. Rousseau, L842 (=Valencien~ 



neneie Etouss. L842, el Valenoiennia^ Bourg. L855.) 

 Shell Large (125 mill, long, l'l broad, 77 high), thin, fragile, 



• Thia genux inhabit* tin- forchts of Al^iirs, where two species arc found on 

 damp rock* away from the water. 



f Thifl r< -inarkahlc genu \h admitted here In deference to Che opinions of 



MM DcxhaycH and Bourguignat. it ■omewhat raeemblei ( 'atnptony^ which 



I • Iim unit-'] witli it. p< rhaps without sufficient cause, under the fourth 



■ rio name \'<tt< nr,< ititr*i>l ! 



