XXII 



HISTORICAL SKETCH. 



Euparypha, Belog. Siph. 

 ( lachea, Belog. Siph. 

 < Macularia Belog. Siph. 

 (^Iberiis, Belog. Siph. 



Coryda, Belog. Euadenia. 

 f Hemicyda, Belog. Siph. 

 I Plebecula, Belog. Siph.? 

 (_ Leptaxis, Belog. Siph. 



Pomatia, Belog. Siph. 

 ( Thelidornus, Epiphallogona. 

 j Cysticopsis, Belog. & Teleoph. 

 j Plagioptycha, Belog. Euad. 

 j Polymita, Belog. Euad. 

 j Liockila, Epiphallog. & Belog 

 ^ Enrycratera, Epiphallogona. 



Polydontes, Epiphallog. 



Helicophanta, Macroogona. 



Panda, Macroogona. 



Stylodon, Macroogona, Belog. 

 { Erepta, Zonitidse. 



Dentellarla, Epiphallogona. 



Cepolis, Belog. Euad. 



Pleurodonta, Epiphallogona. 



Ahostoma, Pupidse. 



( Labyrinthns, Epiphallog. 

 j Isomeria, Epiphallogona. 

 [ Caracolus, Epiphallogona. 

 IPhania, Macroogona? 

 f Thersites, Epiphallogona. 

 ] Merope, Epiphallogona. 

 f Obbu, Epiphallogona. 



Traehia, Epiphallogona. 

 (^ Planispira, Epiphallogona. 



Phasis, Haplogona ? 



Chlor it-is, Epiphallogona. 



Pedinogyra Macroogona. 



Ampelita, Macroogona. 



Solaropsis, ? 

 ( Camena Epiphallog., & Belog. 

 -< Hadra, Epiphallog., & Belog. 

 [Papuina, Epiphallog. 

 f Leptoloma, Belog. Euadenia. 

 | Geotrochus Epiphallog. & Belog. 

 (_ Cymotropis, Epiphallogona. 

 ( Ch/onea, Belog. Euadenia. 

 ! ( Vm/.sm, Belog. Euadenia. 

 | AxiiKt, Belog. Euadenia. 



Callicochlias, Belog. Euadenia. 

 Genus COCHLOSTYLA Fer. Belogona Euadenia. 



The general plan of this arrangement is to establish a series lead- 

 ing from Zonitoid to Bull moid shells; and the characters mainly 

 depended upon in the formation of groups are texture, form of lip, 

 and general contour of shell. In the appreciation of that indefin- 

 able something, which counts for so much in classifying Helices, the 

 authors of Die Heliceen are far beyond all previous work ; and it is- 

 this quality this accurate feeling for subtle affinities for which no 

 good reason can be given in words that has rendered this work the 

 basis of classification for three and a half decades, a long period in 

 so changeable a science as malacology. 



It would be obviously unfair to criticise this great work by stand- 

 ards of the new anatomical classification, for excepting the Haplo- 

 gona, Protogonaand Belogona, the Helices were practically unknown 

 anatomically in 1860. Compared with the new system, it is note- 

 worthy that the Haplogona are mostly grouped together near the 

 Zonitidse, where they unquestionably belong; and many other felic- 

 ities of grouping will be obvious to one looking over the list, besides 

 the genius shown in forming natural suhgenera, already referred to. 

 For the rest, the Epiphallogona, Belogona, Teleophallogona, Proto- 



