MONOTOCARDIA — TAENIOGLOSSA 



419 



the sides, channelled at each end, labium inflected ; no opercu- 

 lum. Jurassic . Genera : Ovula (including Ampliiperas^ 



Transovula, CypTioma^ Radius^ Simnia)^ Pedicularia^ Cypraea 

 (with subg., Cypraeovula, Cypraedia^ and Trivia)^ and Urato, 



Fam. 39. Boliidae. — Foot expanded, wider and longer than 

 the shell, truncated and thickened in front, siphon very long and 

 narrow ; central tooth with very strong median and small lateral 



Fig. 277. 



Three stages in the growth of Pteroceras rugosum Sowb., E. Indies, 

 showing the development of the * fingers.' 



and basal cusps, lateral and marginals bluntly falciform ; shell 

 ventricose, without varices, spire short, outer lip generally simple, 



anterior canal rather wide, no operculum. Cretaceous . 



Genera : Dolium (subg., Malea^ outer lip thickened, denticulate, 

 reflected) ; Pirula^ mantle with two lateral lobes reflected over 

 part of the shell, shell fig-shaped (Fig. 278). 



Fam. 40. Oassididae. — Foot broad, siphon long (radula, Fig. 

 125, p. 223) ; shell ventricose, with varices, spire short, outer 

 lip reflected or thickened, anterior canal short, recurved narrow; 

 operculum semilunar, with ribs radiating from a marginal 



