MONOTOCARDIA RACHIGLOSSA 



425 



Principal genera 



Fig. 2S2.—roluia ni- 

 vosa Lam., West 

 Australia. x *. 



narrow, no operculum. Cretaceous . 



Mitra (with many sections), sulig. StrigatcUa, 

 Mitreola, Mutyca, Dihaijlius ; Plochelaea (Ter- 

 tiary), Thai a ; Turricula (with several sec- 

 tions), Cylindrofnitra, and Imhricai'm. 



Fam. 9. Volutidac. — -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. 



Cretaceous . Principal genera : Cryj^do- 



cliorda (Eocene), Zidona, Provocator, Guivilha, 



Yet us ( = Cymbium), Vohita (with many sections) ; VolutolUhes 



(chiefly Eocene), Volutolyria, Lyria, Enaeta, Volutomitra. 



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

 pendages, mantle largely reflected over the shell ; radula without 

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

 or conoidal, polished, aperture narrow, outer lip 

 thickened, columella with many folds ; no oper- 

 culum. Eocene . Principal genera : Mar- 



ginella, with many sections and so-called sub- 

 genera ; Persicida, Pachylathron (?), 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, Harim 



Fig. l^^^.—OUva par. Uy^Wt ^[RaX 

 phyria Lam., ', 



Panama. 1' AM. 12. Olividae. — Propodium somi-lunar, 



with a longitudinal groove above, mesopodium 

 reflected laterally over the shell ; central tooth of radula tri- 

 cuspid on a very broad base, lateral simple, hooked; shell sub- 

 cylindrical or fusiform, polished ; aperture narrow, operculum 



