576 



MOLLUSCA 



PHYLUM VI 



traced back to the Eocene. Subfamily and generic characters are based largely iijion 

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



Polygyra Say. Globose or dejaressed, 

 Oligocene to Eecent ; North America. 



Sagda Beck. Glossy, with many close 



A, Helix (Dimorphoptychia) arnouldi Michaud. Lower 

 Eocene ; Rilly, near Rhelms. B, HeHx (Campylaea) inflexa 

 Klein. Upper Miocene ; Morsingen. C, Helicodonta osculum 

 Tlioin. Lower Miocene ; Hochheim, near Wiesbaden. 



with the lip reflected, often toothed. 



whorls, the last usually with internal 

 laminae and a sharp lip. Oligocene to 

 Recent ; Antilles. 



Pleurodonta Fischer von Wald. 

 Solid, large, depressed and generally 

 keeled ; aperture often toothed. Oligo- 

 cene to Recent ; Antilles, Florida. 



Helix Linn. (Fig. 1087, A, B). 

 Shell semi-globose, conical to discoidal, 

 manifesting great variability of form. 

 Aperture oblique, crescentic or rounded, 

 with disconnected margins. Very pro- 

 fuse in the Tertiary and Recent of Europe and adjacent regions of Asia and Africa, 



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

 denticulated lip. Oligocene to Recent ; Europe. 



Other allied genera occur in Euroj^ean Tertiary deposits. 

 Recent Helicidae reproducing by extraordinarily large eggs are 

 the following : Helicoiihanta 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 Recent. 



Bulimulus Leach. Oligocene to Recent ; America. Amjihi- 

 dromus Alb. Tertiary ; Europe and Asia. 



A 



Family 3. Pupidae Albers. 



Fig. loss. 



A, Clausilia hulimoides 

 A. Braun. Lower Miocene; 

 Eckingen, near Ulm. B, C. 



Shell small, cylindrical or oval, with narrow ivhorls. Tertiary (^ntiqua Schiibier. Same 

 and Recent ; also in the Carboniferous. 



Clausilia Drap. (Fig. 1088). Shell turreted to fusiform, slender, sinistral. 

 Aperture j^yriform, with usually continuous peristome. Inner lip bearing two folds ; 

 A outer margin somewhat reflected ; the aper- 



ture usually closed by a movable calcareous 

 l^late. Occurs sparingly fossil from the 

 Eocene onward, and represented by about 

 400 Recent 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 Recent. 



Dendropupa Dawson (Fig. 1089, A). 

 Like the last, but aperture without teeth. 

 Upper Carboniferous ; Nova Scotia. 

 Tertiary and Recent. 

 (Fig. 1090). High conical, solid, turreted. 



Fii;. 10.S9. 



A, Dendropupa vetusta 

 Dawson. Coal Measures ; 

 Nova Scotia (after Dawson). 

 B, Pupa diversidens Sandb. 

 Miocene; Sansan, Gers (after 

 Sandberger). 



Vertigo Miiller. 

 Buliminus Ehrb. 



Fio. 1090. 



' Buliminus (Pet raeu.t) 

 c.omjtlanatus Reuss. 

 Lower Miocene; 

 Thaltingen, near Ulm. 



Eocene to Recent. 



