HISTORICAL SKETCH. Xxi 



Heliceen, 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 

 -fill 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 Martensian subgenera falls, these groups 

 being as follows : 



Endodontidce : 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. 



( Amphidoxa, Haplogona. 

 J Microphysa, Teleophallogona. 

 j Aerope, Rhytididse. 

 ^ Pella, Haplog. & Zonitidse, etc. 

 f Patula, Haplogona. 

 Charopa, Haplogona. 



' Acanthinula, Belogona. 



Vallonia, Belogona. 



Petasia, Belogona. 



Fruticicola, Belogona. 



Dorcasia, Protogon a & Belogon a. 

 ^Rhagada, Epiphallogona. 



j Stephanoda, Haplogona. f Xerophila, Belog. Siphonadenia. 



(Rhytida, Rhytididse. -< Turricula, Belog. Siph. 



Jattulus, Zonitidse. (^ Cochlicella, Belog. Siph. 



Endodouta, Haplogona. ( Ochthephila, Belogona. 



Sesara, Zonitidse. < Actinella, Belogona. 



Pelia, Zonitidse. (_ Tectula, Belogona. 



Gonostoma, Belog. si phonadenia. ( Plectotropis, Belog. Euadenia. 



Ophiogyra, Protogona ? | Aegista, Belog. Euad. 



JPolygyra, Protogona. f Aglaia, Belog. Euad. 



Stenotrenia, Protogona. J Campy Icea, Belog. Siph. 



j Triodopsis, Prolog. & Belog. 1 Eurycampta Belog. Euad. 



\ Mesodon, Protogona. [^Arionta, Belog. Siph. & Euad. 



Laoma, Polyplacognatha. Eurygioma, Epiphallogona. 



