316 LITTORINID.E. 



Genus ECFIINELLA, Swainson. 



Operculum circular, many-whorled. 



Shell turbinately conoidal, axis more or less distinctly 

 perforated, whorls muricate or granulated; aperture ovate; 

 inner lip arcuate, edentulous, or with an obscure tooth-like 

 callus at the fore part ; outer lip acute. 



Syn. Nina, Gray. 



Ex. E.Cumingii,P/«7«|)/>2, pi. 33, fig. 3. Operculum, 

 E. Cumingii, fig. 3, a, 3, h. 



In E. coronaria the tooth is inconspicuous, but the 

 axis is perforated, and the operculum is orbicular and 

 raany-whorled ; the same characters are present in E. Cu- 

 mingii^ which constitutes the type of the iV/wa of Gray. 



Species of Echinella. 



coronaria, Lam. granulata, Sivains. 



Cumingii, Phil. 



Genus MODULUS, Gray. 



Eyes on the middle of the tentacles. 



Operculum orbicular, many-whorled. 



Shell turbinate, depressed or trochiform, porcellanous, 

 axis perforate ; aperture oval ; inner lip with a strong, 

 plait-like tooth at the fore part ; outer lip acute. 



Syn. Monodonta, Swains., not LatJi. 



Ex. M. tectum, Gmelin, pi. 33, fig. 4. Operculum, 

 M. tectum, fig. 4, a, 4, h. Shell, M. lenticularis, Chem- 

 nitz, fig. 4, c. 



