SUB-ORDER B 



PLATYPODA 



473 



posteriorly produced in a usually short canal. Outer lip inflected. Operculum wanting. 

 Upper Jura to Recent. 



Recent Gypraeidae, of which about 210 species are known, inhabit prinrijially tin- 

 wanm-r seas. They are often remarkable for their beautiful coloration, and .-HIM -t inn - 

 attain considerable size. Jurassic species are sparse; Tertiary ones rather more abundant. 



Cypraea, Linn. (Fig. 951). 

 Ovoid, ventricose, enamelled, 

 smooth, lirate, or tuberculate ; 

 spire exposed or enveloped. 

 Aperture narrow, extending t In- 

 whole length of the shell, and 

 canaliculate at each extremity. 

 Inner lip and the inrolled outer 

 lip generally crenulate. Jura Flo 951 



(G. titonica, Stefani) to Recent. ~ !'" 952. 



Trivia, Gray (Fig. 952). 



T ., , T i n ^ c c ! Weinheini, 



Like the preceding, but smaller, near Alzey. 



subexcisa, 

 raun. Oligo- Trivia affinix, l>n.j. 



Erato laevix, Dmi. 

 Miocene ; NiederleiH, 



Austria. 



lt -> *"M' 



i ; Pont- 

 levoy, Touraine. 



and sculptured with raised 



transverse riblets. Anterior channel not prolonged, wide and slightly reverted. 



Tertiary and Recent. 



Erato, Risso (Fig. 953). Small, ovoid or pyriform, with short conical spire. 

 Aperture narrow. Inner lip smooth, except for anterior columellar folds ; outer lip 

 denticulate. Canal notch-like, broad. Cretaceous to Recent. 



Family 22. Ovulidae. 



Like the Cypraeidae, except that the spire 



FIG. 954. 

 Gisortia tuberculosa, Duclos. Lower Eocene ; Cuise-la-Mothe. 



ture anteriorly and posteriorly with a short canal. 

 Goldf. sp. 



Pedicularia, Swainson. Miocene to Recent. 



is convolute instead of produced and 

 covered, and the marginal teeth 

 of the radula are peculiarly 

 modified. Tertiary and Recent. 



Ovula, Brug. Shell ovate 

 or fusiform, the spire completely 

 enveloped. Aperture produced 

 anteriorly and posteriorly as a 

 canal. Inner lip smooth ; the 

 outer inflected, smooth, or den- 

 ticulated. Tertiary and luvmi. 



Gisortia, Jousseaume (Fig. 

 954). Large, thick - shelled, 

 ovate, with short convolute 

 spire. Surface typically keeled 

 or coarsely tuberculate. Body 

 whorl with a blunt ridge ; aper- 

 Eocene. G. (Strombus) gi<j<int"i. 



Family 23. Cassididae. Adams. 



Shell thick, inflated, globularly ovate, sometimes varicose; spire short, body whorl 

 very large. Aperture narrow, elongate, anteriorly with short canal. Inner lip resting on 

 an extensive callus, sometimes granulated or wrinkled. Outer lip more or less thickened. 

 Operculum horny, with marginal nucleus. Marine. Upper Cretaceous to Recent. 



