XXXIV CLASSIFICATION OF HELICES. 



b. Whorls rounded at periphery; South American 



Polygyratia, p. 81. 



bb. Whorls carinated at periphery; Papuan region 



Coxia, p. 83. 



aaa. Jaw solid, smooth ; penis sack continued slightly beyond 

 insertion of vas deferens ; duct of spermatheca long; shell 

 globular or depressed-globose; S. African, Dorcasia, p. 172. 



Tribe II, MACROOGONA. 



a. No blind sack or appendicula on vagina or spermatheca duct. 

 Eggs or young at birth very large, about one-third the 

 diameter of adult shell. ; shell with more less reflexed lip, the 

 embryonic whorls distinctly demarked from after growth. 



b. Shell keeled, at least when young, imperforate, 

 finely wrinkled, the embryonic 3$ whorls spirally 

 grooved or decussate ; columella short, vertical, its 

 inner edge with a convex lobe or acute fold. Vivi- 

 parous, Seychelles Is. Stylodonta, p. 149. 

 bb. Shell capacious, not keeled ; embryonic whorls 

 over one-third diameter of adult, post-embryonic 

 growth 1 whorls or less. Aperture large, lip nar- 

 row, dilated at columellar insertion ; columella 

 concave, toothless. Madagascar 



Helicophanta,p. 151. 



bbb. Shell imperforate, globose-depressed or trochoidal, 



not carinated, solid, bright colored; embryonic 



shell about i diameter of adult. Lip broadly 



reflexed, vividly colored Acavus, p. 153. 



aa. No blind sack on vagina or spermatheca duct ; junction of 



nuclear shell with after growth not distinct ; lip expanded or 



reflexed. 



b. Shell acutely keeled, at least when young; lip 

 usually bright colored, the columella widened into 

 a flat plate. Moluccas Pyrochilus, p. 154. 



bb. Shell umbilicate (except in Poacilostylus), the lip 

 not bright colored, not widened at columella. 

 Madagascar Ampelita, p. 155. 



aaa. Vagina or spermatheca duct bearing a blind sack. Lip of 

 shell narrow or simple. Eggs and embryonic shell smaller. 

 b. Shell Helicoid, umbilicate, wider than high. 



