MITRIDiE. 167 



Species of Lyria. 



cassidula, Reeve. lyrfeformis, Sn-ains. 



Delessertiana, Petit. mitriforniis, Lam. 



lyrata, Humph. nucleus, Lam. 



Sub-gen. en^eta, H. and A. Adams. 



Shell ovately pyramidal, thick, solid ; spire acuminated, apex 

 acute, whorls ribbed or nodulose ; outer lip thickened, inflexed, 

 with an obtuse tooth in the middle. 



Cumingii, Brod. guttata, Reeve. 



cylleniformis. Sow. harpa, Barnes 



Guildingii, Sow. 



Genus VOLUTILITHES, Swainson. 



Shell ovately fusiform ; spire elevated, apex acute, 

 whorls longitudinally plicate or cancellated ; aperture 

 oval-oblong ; columella with numerous faint, rudimentary 

 or obsolete plaits ; outer lip thin, simple. 



Ex. V. abyssicola, Adams and Reeve, pi. 18, fig. 8. 



The only living representative of this genus at present 

 known was dredged from a depth of one hundred and 

 thirty-two fathoms off the Cape of Good Hope, during 

 the voyage of H.M.S. Samarang ; fossil species are nu- 

 merous in the eocine portion of the tertiary beds of the 

 British Isles. 



Fam. MITRID.^. 



Head small and narrow ; tentacles close together at the 

 base ; eyes above the base or towai'ds the outer middle 



