232 I.IITMKINII. 



Gen... PURFURINA, d'Orb, I860. 



Shell narrowly perforate, turbinate. rentricOfle, thick, \vliorl> 

 rounded. ehanneled at the suture. longitudinally ribbed, spirally 

 Striate; aperture oval, >ul)channeled in front, columella arcuateil. 



ipfe, iv : \. d'orh. ( Pl. }<>. i Jurassic, 



MODULUS, Gray, 1*40. 



tnfewlj umbilieated. t<p-shaped, solid, grooved or ribbed and 

 tuheivulate : coliiinella -rooved, ending below in a sharp tooth. 



vuluiii niultispiral. Animal with loiiir. cylindrical tentacles, 

 hearing eyes at al>out hall' tlieir len-'th, mantle maririn <Vin. 

 foot truncate in front, attenuated lehind. M. TKCTUM, Ginel. 

 Then an a!oiit a hall' do/en sj>ecies, living in warm seas. Denti- 

 tion. PI. 4. li- 71. 



Genus RISELLA, Gray, IMn. 



Shell trochifoi-in, with Hat whorls, angular periphery and con- 

 cave bast-, imperiorate ; aperture rhomboidal, lip simple, usually 

 ln. \\n-inargint-d within. Operculum ])aucis]>iral. 

 , Eyes on short jM-dnndc- at the base of the tentacles. Dentition, 

 PI. \ 11 MI.L.VNOSTOMA, Ginel. 



Sub-enus PI;.\SM:KLA, Xevill. 



Shell iiinbilicatrd <ir jierforate. Opemiliini coneentric, inulti- 

 \M II.I.A. ( ioidd. 



l, J/ltlldll. 



PI.K-K 'i i:icnr>. Fischer, 187s. 



Inij>erfo|-ate, el.iiL r ately conic, whorls nunierous; aperture sub- 

 rhonih-.idal, >iMMth within, prol..uM V d into a >hort canal below, lip 

 subrostriit. in the middle. K. SoUVEBBIANA, Kischcr. 



( 'ah ilnn in. 



Subgenu- LnnrOTBOCHUB, I-!. A. Smith, 1>- 



Umbilieated. OOnic, >pirally rid-ed. ajH-rtiin- >m...,th within, the 

 lip iibliijiic. basal mar-in broadly sinuated, columella some- 

 what reflected, united to the lip above by a callnsitv. L ; -]). 



. /. . A\ ualer). 



Scarcely s-]arabl.- fn.m tin- |>reeedi ni r ,. X ee])t by its dilirn-ut 

 habit and locality. \\. TROMBOin, V.. A. Smith. 



