MONOGRAPH OF THE GENUS STROPHIA. 
185 
months, been kept in a box, with others, and although some showed 
signs of life during the summer of 1893, they have, so far as I have 
observed, all remained quiet up to this time. Of course they have 
been kept in a warm room and in the drawer of a cabinet, where they 
have been hut little disturbed. This incident is very instructive as 
showing the great length of time in which at least individuals, of this 
group of animals can live under adverse circumstances. See further 
remarks on this head under Strophia gray! and S. ritchiei. 
36 STROPHIA RITCHIEI Novo. 
Ritchie’s Strophia, 
Fig. 41. A, front ; B, side view of type. 
DESCRIPTION. 
Whirls, 
Fig. 41. 
Sp. Oh. Size large. Shell, heavy. Striations, present 
ten. Examined, 1,000 specimens. 
Form of shell, inclined to be cylindrical ; the first two whirl 
being equal in size and the third is but 
little smaller, and from this the shell 
slopes to a rather rounded point, form- 
ing an angle of sixty-five degrees. 
The striations are rather nume- 
rous, twenty-three to the first whirl, 
are regular, but not arranged in lines, 
about as wide as the interspaces be- 
tween them, and although rounded and 
smooth, without furrows, are not 
polished. 
Aperture, not very small, and 
open. Lower tooth large and promi- 
nent, about .08 high, and about as 
wide at the base as it is high, and 
nearly one and one half times as long 
•as high. Its position is central, and it is set back a little less than its 
length. Upper tooth represented by a slight tubercle. 
Margin, produced forward nearly as far as the diameter of the 
shell, and is slightly inclined to the right, slightly beyond the diameter 
of the shell. It is thin and rounded, but not produced into any edge 
whatever. The frontal bar is extremely well developed, and so com- 
B 
Strophia ritchiei, 
of type 
A, front'; B, side vievf 
