M 1 T R A rigida. 

 Ribbed Mitre — 7niddle figures. 



Specific Character. 



M. testa cost is longitud'malihus, elcvatls, linear ihus, integris, interstitiis lavihm 

 ad basin granulat is ; spira producta ; columella Ar-plicata ; apertura brevi. 



Shell with elevated, longitudinal, obtuse, entire ribs, the interstices smooth, 

 the base granulated; spire lengthened; pillar four-plaited; aperture 

 short. 



Equally rare, and from the same collection as die preceding. 

 In habit it approaches nearest to M.exasperata of Chemnitz, 

 but has not the ribs angulated or their interstices striated, and 

 is much more narrowed at the base than in that shell, which I 

 have seen : the outer lip is also smooth ; the inside strongly 

 striated. This shell was formerly in the collection of Mr. Keate, 

 the elesjant author of the " Sketclies from Nature." 



