MONOTOCARDIA— RACHIGLOSSA 



425 



narrow, no operculum. Cretaceous- 



ni- 

 vosa Lam., West 

 Australia, x |. 



Principal genera 

 Mitra (with many sections), subg., Strigatella^ 

 Mitreola^ Miityea^ Dibaphiis ; Plochelaea (Ter- 

 tiary), Thala ; Turricula (with several sec- 

 tions), Oylindromitra^ and Imhricaria. 



Fam. 9. Volutidae. — Foot broad in front, 

 head laterally dilated into lobes, on which 

 are placed the sessile eyes ; siphon prominent, 

 with appendages at the base (radula, Fig. 122, 

 p. 221) ; shell thick, often shining, fusiform, 

 globular or cylindrical, columella projecting 

 anteriorly, with several folds, the anterior of 

 which is the largest, aperture notched, canal 

 not produced, operculum generally absent, fig. 2%2.— Voiuta 



Cretaceous . Principal genera: Crypto- 



chorda (Eocene), Zidona^ Provocator^ G-uivil 

 lea^ Yetus Q= Oyinhiuni)^ Voluta (with many sections), FbZw^o- 

 Uthes (chiefly Eocene), Volutoly^na^ Lyria^ Enaeta^ Volutomitra. 

 Fam. 10. Marginellidae. — Foot broad, siphon without ap- 

 pendages, mantle largely reflected over the shell ; radula with- 

 out laterals, central tooth comb-like, cusps rather blunt; shell 

 oval or conoidal, polished, aperture narrow, 

 outer lip thickened, columella with many 

 folds; no operculum. Eocene . Prin- 

 cipal genera : Marginella^ with many sections 

 and so-called sub-genera; Persicula^ Pachy- 

 bathron (?), Cystiscus^ Microvoluta. 



Fam. 11. Harpidae. — Foot large, with a 

 transverse groove, separating off a semi-lunar 

 propodium ; mantle partly reflected over the 

 shell ; shell ventricose, polished ; spire short, 

 strongly longitudinally ribbed, ribs prolonged 

 over the suture, columella callous ; no oper- 

 culum. Eocene . Single genus, Harpa 



Fig. 283. -0^^^;a por- (gub^., iS'l'Zm). 

 j37i?/na Lam., Panama. -r? ^ o •^t • • -r t-» t 



l^AM. 12. Olividae. — Fropodmra semi- 

 lunar, with a longitudinal groove above, 

 mesopodium reflected laterally over the shell ; central tooth of 

 radala tricuspid on a very broad base, lateral simple, hooked ; 

 shell sub-cylindrical or fusiform, polished; aperture narrow, 



