4 

 Planorbis nautileus, Z. 



Planorbis nautileus, v crista, L. 

 Planorbis albus, Aliill. 



Planorbis albus, v Draparnaldi, Shepp. 

 Planorbis parvus, Say, (P. glaber, y^/f^) 

 Planorbis dilatatus, Gould. 



Planorbis dilatatus, v compressa, Lloyd. 

 Planorbis spirorbis, Mull. 



Planorbis spirorbis, v ecarinata, Jeff. 



Planorbis spirorbis, v albida, Nelson. 

 Planorbis vortex, L. 



Planorbis vortex, v compressa, Mich. 

 Planorbis carinatus, Midi. 



Planorbis carinatus, v disciformis, Jeff. 

 Planorbis complanatus, Z. 



Planorbis complanatus, v rhombea, Tnrt. 



Planorbis complanatus, v albina, Jeff. 



Planorbis complanatus, m sinistrorsum, Taylor. 



Planorbis complanatus, m terebrum, Ti(i\ 

 Planorbis corneus, Z. 



Planorbis corneus, v albinos, Moq. 

 Planorbis contortus, Z. 



Planorbis contortus, v albida, y^j^ 

 Genus II. — Physa, La7n. 

 Physa hypnorum, Z. 



Physa hypnorum, v major, Charp. 



Physa hypnorum, m decollatum. Nelson. 

 Physa fontinalis, Linn. 



Physa fontinalis, v inflata, Moq. 



Physa fontinaUs, v curta, Jeff. 



Physa fontinalis, v oblonga, Jeff. 



Physa fontinalis, v albina, Jeff. 



Genus III. — Limnaea, Brugiere. 



LlMN^A GLUTINOSA, Mull. 



Limnasa glutinosa, v mucronata, Jeff. 

 LiMN^EA INVOLUTA, Tkonipson. 



LiMNiEA PEREGRA, Miill. 



