576 



MOLLUSCA 



PHYLUM VI 



traced back to tlie Eocene. Subfamily and generic characters are based largely upon 

 the genital System, and hence are of little practical importance to the paleontologist. 



Polygyra Say. Globose or depressed, 

 Oligocene to Eecent ; North America. 



Sagda Beck. Glossy, with many close 



Fig. 1087. 



A, Ilelix (DniiorplioptycMa) arnouldi Michaud. Lower 

 Eocene ; Rilly, near Rheims. B, Helix (Campylaea) inflexa 

 Klein. Upper Miocene ; Mörsingen. C, Helicodonta osculum 

 Thoni. Lower- Miocene ; Hochheim, near Wiesbaden. 



with the lip reflected, often toothed. 



whorls, the last usually with internal 

 laminae and a sharp lip. Oligocene to 

 Eecent ; Antilles. 



Pleurodonta Fischer von Wald. 

 Solid, large, depressed and generally 

 keeled ; aperture often toothed. Oligo- 

 cene to Eecent ; Antilles, Florida. 



Helix Linn. (Fig. 1087, Ä, B). 

 Shell semi-globose, conical to discoidal, 

 manifesting great variability of form. 

 Aperture oblique, crescentic or rounded, 

 with disconnected margin s. Very pro- 

 fuse in the Tertiary and Eecent of Europe and adjacent regions of Asia and Africa. 



Helicodonta Fer. (Fig. 1087, G). Similar to Helix, but with thickened or 

 denticulated lip. Oligocene to Eecent ; Europe. 



Other allied genera occur in European Tertiary deposits. 

 Eecent Helicidae reproducing by extraordinarily large eggs are 

 the foUowing : Helicophanta of Madagascar, Acavus of Ceylon, 

 Panda of Australia, and Strophocheilus of South America. 



Family 2. Bulimulidae Fischer. 



Shell elongated, ovate, with narroio umhilicus or none. Ter- 

 tiary and Eecent. 



Bulimulus Leach. Oligocene to Eecent ; America. Amphi- 

 dromus Alb. Tertiary ; Europe and Asia. 



Family 3. Pupidae Albers. 



Shell small, cylindrical or oval, with narroio whorls. Tertiary 

 and Eecent ; also in the Carboniferous. 



Glausilia Drap. (Fig. 1088). Shell turreted to 

 Aperture pyriform, with usually continuous peristome. 



lOSS. 



A, Glausilia hulimoides 

 A. Braun. Lower Miocene ; 

 Eckingen, near Ulm. B, C. 

 antiqua Schübler. Same 

 locality. 



fusiform, slender, sinistral. 

 Inner lip bearing two folds ; 

 outer margin somewhat reflected ; the aper- 

 ture usually closed by a movable calcareous 

 plate. Occurs sparingly fossil from the 

 Eocene onward, and represented by about 

 400 Eecent species. 



Pupa Lam. (Fig. 1089, B). Shell small, 

 cylindrical- ovate. Aperture semicircular, 

 usually constricted by teeth on the colu- 

 mella and inner and outer lips. The outer 

 margin reflected. Tertiary and Eecent. 



Dendropupa Dawson (Fig. 1089, Ä). 

 Like the last, but aperture without teeth. 

 Upper Carboniferous ; Nova Scotia. 

 Vertigo Müller. Tertiary and Eecent. 

 Buliminus Ehrb. (Fig. 1090). High conical, solid, turreted. Eocene to Eecent. 



Fig. 1089. 



vetusta 



A, Dendropupa 

 Dawson. Goal Measures ; 

 Nova Scotia (after Dawson). 

 B, Pupa diversidens Sandb. 

 Miocene ; Sansan, Gers (after 

 Sand berger). 



Fig. 1090. 



'Buliminus (Petraeus) 

 complanatus Reuss. 

 Lower Miocene; 

 Thalflngen, near Ulm. 



