CHAPTER VI 
UNIVALVE MOLLUSKS 
A strange little shell is that shown in 
Migure 93, and a fairy tale it could tell 
of the life of its little inhabitant. Shaped 
like the tusk of an elephant, pure white 
and open at both ends, it differs widely 
from all other kinds of shells. The name 
of this species is Dentalium preciosum, 
Nutt., the Precious Tusk-shell. It has also been 
ealled D. indianorum, and with good reason, for 
in former years the Indians used to gather them 
from the little bays on the west coast of Vancouver 
Island and string them for wampum. ‘The Tusk- 
shell lives partly buried in the sand. An inch is 
perhaps an average length for shells of this 
species. 
Dentalium neohexagonum, 8. & P., the Hexa- 
gonal Tusk-shell, is the common species of south- 
ern California. Sometimes the shells are two 
inches in length, and as the name indicates, a cross 
section would be six-sided. The shell is thin, white, 
eurved and angled. This species was called D. 
hexagonum in West Coast Shells, but that name 
is found to belong to an oriental species. 
Dentalium semistriatum, var. semipolitum, B. 
& S., the Ornamented Tusk-shell, isa small species 
that lives in the south. Its shell is thin, white, 
and ornamented with numerous fine ridges run- 
Fig. 93 
