HISTORICAL SKETCH. XXI 



Heltceen, edited by von Martens, marked a period closed, and a new 

 epoch begun. 



As the classification given in this work has been the basis of nearly 

 all subsequent systematic arrangements, it is here quoted in full 

 The brackets indicate that groups so united are supposed to be 

 closely allied. For purposes of comparison I have given in Roman 

 type the names of the super-generic groups of this volume, under 

 which each of the Albers Martensiau subgenera falls, these groups 

 being as follows : 



EndodonlidcE : Haplogona, Polyplacognatha. 



Helicidce : Protogona, Teleophallogona, Epiphallogona, Belogona 



(with two divisions, Bel. Euadenia and Bel. Siphonade- 



nia), Macroogona. 



Vitrinea. 



Genus SAGDA Beck (Teleophallogona). 



Hyalosagda, Proserpinula, Odontosagda. 

 Genus LEUCOCHROA Beck (Belogona). 



Helicacea. 



Genus HELIX L. 



( Amphldoxa, H aplogona. 





Microphysa, Teleophallogona. 

 Aerope, Rhytididse. 



Acanthinula, Belogona. 

 Vallonia, Belogona. 

 Petasia, Belogona. 



I yao/wy^c/, \ii>j tuaiucc. i j. c/i/we ni, jjcivjguiio. 



l^Pella, Haplog. & Zonitidse, etc. ] Fruticicola, Belogona. 

 f Patnla, Haplogona. Z>orcosia,Protogona&Belogona. 



j Charopa, Haplogona. {^Rhagada, Epiphallogona. 



"} Stephanoda, Haplogona. C Xerophila, Belog. Siphonadenia. 



(^Rhytida, Rhytididse. -< Tum'cula, Belog. Siph. 



Jamilug, Zonitidse. (_ Cochlicella, Belog. Siph. 



Endodonta, Haplogona. ( Ochthephila, Belogona. 



Sesara, Zonitidse. -< Actinella, Belogona. 



Pelia, Zonitidse. ( Tectula, Belogona. 



Gonostoma, Belog*. si phonadenia. f Plectotropis, Belog. Euadenia. 



Ophiogyra, Protogona? ( Aegista, Belog. Euad. 



| Polygyra, Protogona. ( Aglaia, Belog. Euad. 



i{ Stenoirenia, Protogonii. j Campylcea, Belog. Siph. 



J Triodopsis, Protog. & Belog. j Eurycampta Belog. Euad. 



{ Mesodon, Protogoaa. [Arionta, Belog. Siph. & Euad. 



Laoma, Polyplacognatha. Eurystoma, Epiphallogona. 



