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. 
