UNIVALVES. BULLA. 89 



DIVISION III. SHELL THIN, GIBBOUS, AND APERTURE 



LARGE. 



FAMILY 1. Apex generally umbilicated and without aspire. 

 Naucum Sea-nut. Amygdalus Almond. 



*Aperta Wide- *Lignaria Brown-striated. 



*Catena Chain. Pectinata Pectinated. 



*Plumula Feather. Soluta Unsealed. 



*Hydatis Paper. *Akera Elastic. 



Ampulla Pewet's-egg. C ylindrica Cylindric. 



Velum White- banded. 



Shells Minute. 



*Cylindracea Cylindrical. *Retusa Blunt. 



*Umbilicata Umbilicated. *Obtusa Obtuse. 



FAMILY 2. Having a spire. 

 Physis Striped. Zonata Zoned. 



Amplustre Banded. Undulata Undulated. 



Scabra Rough. 



DIVISION IV. SHELL PYRIFORM, WITH PRODUCED BEAK. 



Ficus Fig. Rapa Turnip-shaped. 



Pyrum Pear. Canaliculata Channelled. 



DIVISION V. SHELL GENERALLY THIN, SPIRE PROMINENT, 



AND BODY WHIRL INFLATED. 



Voluta Volute. Strigata Yellow- streaked. 



Dominicensis Nine-whirVd. Striatula Striated. 



Crassula Reversed. . Exarata Wrlnlded. 



*Fontinalis Fresh-water. Truncata Truncated. 



*Rivalis River. Priamus Priam. 



*Hypnorum Slender. Zebra Zebra. 



Gelatinosa Gelatinous. Achatina Broad- strip* d. 



Virginea Ribbon. Purpurea Purple-mouth' 'd. 



Fasciata Banded. Sinistrorsa Great-revers'd. 



DIVISION VI. SHELL CYLINDRICAL, WITH A SUBULATE SPIRE 



AND TRUNCATE BASE. 



Terebellum Awl-shaped. 



