SHECES WiITHOUM CANALS 221 
shells. Some of them are found on the backs of 
old abalone shells, while others cling to rocks 
or alge. They are generally slender and horn- 
shaped, and so minute that a microscope is needed 
to observe them satisfactorily. Since they are too 
small te be easily identified, they will not be 
described here, but will be mentioned in the List, 
for the guidance of those who wish to pursue the 
subject of the identification of the minute mollusea. 
Fuminicola fusca, Hald, the Tawny 
Flood-shell, Figure 240, inhabits rivers, 
as its name indicates. The shell is about 
Fig. 240 the size of a pea, quite solid, with a short, 
three-whorled spire. The operculum is horny, and 
the color is greenish. The figure was drawn from 
a specimen found in Malad River, Utah. 
Flumilicola nuttalliana, Lea, Nuttall’s 
Flood-shell, Figure 241, probably in- 
habits the entire Columbia Valley. The 
shell is longer and more slender than 
that of the last species, greenish-brown 
without, whitish within. The shell is from one- 
fourth to one-half an inch in length. This species 
includes the old species, I’. hindsiz, Baird. 
Fluminicola virens, Lea, the Green Flood-shell, 
is a northern species, found in Oregon, Washing- 
ton, and on Vancouver Island. It is about one- 
fourth of an inch long, remarkably thick, green, 
with inflated whorls and ovate aperture. 
Fluminicola columbiana, Hemphill, the Colum- 
bia Flood-shell, has a globose shell, with a very 
short spire; dark olive or brown color, the four 
Fig. 241 
