178 CONTRIBUTIONS 



Observations. This species differs from the last in 

 being broader, in having a shorter spire, in having one 

 fold less, and in being thicker in the lip. 



M.plicata. Plate 6. Fig. 189. 



Description. Shell ovate, longitudinally folded above ; 

 substance of the shell rather thick ; spire short, rounded 

 at the apex ; whorls three, flattened above ; columella 

 with six folds ; mouth narrow, curved ; outer lip thick, 

 finely crenulate within. 



Length 5-20ths, Breadth 3-20ths, of an inch. 



Observations. Differs from all the species herein de 

 scribed, in having longitudinal folds, which are placed on 

 the superior part of the whorls. 



M. semen. Plate 6. Fig. 190. 



Description. Shell ovato-elliptical, polished ; substance 

 of the shell rather thick ; spire very short and rounded at 

 the apex ; whorls three, flattened above ; columella with 

 six folds ; mouth narrow, curved ; outer lip somewhat 

 thick and very minutely crenulate within. 



Length 5-20ths, Breadth 3-20ths, of an inch. 



Observations. This species seems most analagous to the 

 last described, but is without its exterior folds, and is more 

 elliptical. 



