162 CONTRIBUTIONS 



or furrow, which I believe is always attendant on the 

 horn, exists distinctly in every individual of the three 

 species which I have. The angular points within the 

 furrow satisfy me entirely that, when perfect specimens 

 are procured, the horn will be found at the termination of 

 the furrow on the edge of the lip. This furrow may be 

 observed more or less distinct on all the recent species, at 

 least they exist on the nine recent species which are in 

 my cabinet. It is somewhat singular, that Lamarck 

 should not have mentioned this furrow, which seems 

 necessarily attendant on the horn. That naturalist de 

 scribes only five species, all of which are recent. 



M. fusiformis. Plate 5. Fig. 167. 



Description. Shell subfusiform, rather inflated, trans 

 versely striate above and furrowed below ; substance of 

 the shell thick ; transverse furrow linear, with indistinct 

 angular points ; spire rather short, subgranulate, pointed ; 

 suture small; whorls six, rather flattened; umbilicus none; 

 mouth ovate, rather narrow; columella thickened; outer 

 lip sharp. 



Length .8, Breadth .5, of an inch. 



Observations. At first view this species might easily be 

 mistaken for the last. In some characters, however, it is 

 very distinct. Its being without an umbilicus at once dis 

 tinguishes it. The spire is also more elevated. See the 

 remarks on the horn of the last described. 



