MONOGRAPH OF THE GENUS STROPHIA. 
19 
Form of shell, a pointed oval, with the second whirl the largest; 
the first and third are about the same size and from the third, the shell 
tapers to quite a blunt point, forming an angle of about 60 degrees. The 
lines of growth are very faintly defined, and become prominent only on 
the top of the first whirl. These prominences begin on a line with the 
frontal bar, and end at a point about half way up the margin, on the 
right, thus occupying the top of the whirl, ending abruptly on the line 
drawn, the shell below this being smooth. Sutures, not deep. 
Aperture, rather small, but open, and the diameter of the cavity 
just within is a trifle more than at the entrance. Lower tooth, about 
central in position, and is .18 long by .05 high; the upper is situated just 
above it, is only .03 high, but makes a complete turn around the column. 
The margin is not produced forward beyond the diameter of the 
shell, it is not very thick, measuring only .08, and is provided on the 
outer posterior portion with a rather blunt edge which unlike the ma- 
jority of species, is not rolled backward. The frontal bar is not very 
well developed, and the lines of growth appear within it. 
Color of shell externally, bluish white, marked with rather zig zag 
longitudinal spottings of purplish brown, that are more numerous on the 
lower whirls. The margin, externally and internally, and the teeth 
are yellowish, but this color gradually deepens within to a purplish 
brown, which color pervades the lower wall and whole interior. 
DIMENSIONS. 
Sizes of types, .96 by .40 and .86 by .39. Largest specimen, 1.04 
by .41. smallest, .83 by .36. Greatest diameter, .46; smallest, .36. 
Longest specimen, 1.04; shortest, .83. 
OBSERVATIONS. 
The type is very constant and the principal departure from it, is a 
form that is proportionately longer and more cylindrical, but tapering 
from the second whirl to the apex. Individuals are shorter and with a 
larger diameter than the types, but scarcely constitute even a group. 
In color the inclination is to be redder in markings, than the types, and 
although a few show broader stripes, the tendency is to exhibit norrower 
ones, with broader areas of white. The margin is never very heavy, .10 
being the extreme measurement, and the fact that the outer posterior 
portion is not rolled backward, is a marked feature and quite constant. 
The restriction of the prominent lines of growth, to the top of the first 
whirl is a usual, though not absolutely, constant character, it being ex- 
tended in some specimens, to the lower part of the whirl, but does not 
extend very far back. 
