XXXVI CLASSIFICATION OF HELICES. 



bb. Penis retractor inserted on epiphallus ; Old World. 

 c. Penis with a feather-shaped appendix ; jaw 

 smooth Obba, p. 107. 



cc. No such appendix. 



d. Apex or whole shell with points in 



quincunx ; jaw ribbed Chloritis, p. 117. 



dd. Genitalia unknown ; jaw ribbed ; shell 



imperforate, with columella wide above 



Albersia, p. 124. 

 ddd. Not so sculptured. 



e. Solid, capacious, rough sculp- 

 tured ; embryonic shell rather 

 large Camcena, p. 101. 



ee. Rather solid, depressed, depress- 

 ed-globose or keeled Thersites, 

 p. 125 ; Planispira, p. 110. 

 eee. Trochoidal, thinner and mostly 

 light colored Papuina, p. 136; 

 Ganesella, p. 168. 

 em. Epiphallus or flagellum more or less obsolete. 



b. Epiphallus more or less obsolete, flagellum present 



Polydontes, etc., p. 87- 



bb. Epiphallus and flagellum obsolete Cristigibba, 



p. 112. 



Tribe V, BELOGONA. 



a. Mucus glands sacculated, club-shaped, bulbous or flattened, 

 glandular, inserted on dart sack or at its base, never on vagina 

 above dart sack (except in Lysinoe, p. 191, in which there are 

 3 club-shaped glands on vag.) Belogona Euadenia, p. 175. 

 aa. Mucus glands tubular or finger-like (except in Elona, p. 307), 

 and always inserted on vagina, never on dart sack or accessory 

 sacks Belogona Siphonadenia, p. 235. 



KEY TO GENERA BY SHELL CHARACTERS. 



A key to groups of Helices based upon shell features only, cannot 

 be made without numerous double entries, and even then to be 

 exhaustive if would be extremely complicated, probably too com- 

 plex to be of use to beginners in the science, for whom alone it 



