TO GEOLOGY. 149 
Observations. This beautiful species differs from those 
above described, in having shorter folds and in being 
covered with minute striae, which are alternately larger 
and smaller, and resemble the finest lines of the graver. 
F. acutus. Plate 5. Fig. 153. 
Description. Shell subfusiform, furnished with large 
longitudinal folds on the middle of the whorl, closely 
covered with transverse alternate striz ; substance of the 
shell thin; spire rather elevated, acutely pointed ; whorls 
seven, subangular; canal rather short, much curved ; 
mouth subrotund ; outer lip sharp. 
Length .6, Breadth 5-20ths, of an inch. 
Observations. In general outline it resembles the last 
described, but may be distinguished at once by the trans- 
verse strize, which in this are not so fine. The canal is 
much more curved. 
F. Conybearii.* Plate 5. Fig. 154. 
Description. Shell subfusiform, furnished with longitu- 
dinal folds cut by rather large transverse striz ; substance 
of the shell rather thick; spire somewhat elevated, point- 
ed; whorls six; canal rather short, oblique ; mouth sub- 
ovate ; outer lip thickened, within crenate. 
Length .4, Breadth .2, of an inch. 
Observations. This species resembles the two last. It 
* Named after one of the distinguished authors of the ‘‘ Outlines of 
the Geology of England and Wales,” the Rev. Mr Conybeare. 
