14 
MONOGRAPH OF THE GENUS STROPHIA. 
This species may be distinguished from the sub species S. m. poli- 
ita, as described under observation in that form, from all others by the 
thin, scarcely flanging margin, numerous striations, and pale brownish, 
usually unbroken, longitudinal markings. 
62 STROPHIA MARMORATA POLITA. Novo. 
Polished Strophia. 
Plate III, Fig. 3, front, fig. 4, side view of type. 
DESCRIPTION. 
Size, medium. Shell, rather thick and heavy. Striations, absent. 
Whirls, 9, the upper, including margin, being about equal in length to 
all of the others put together. Examined 25 specimens. 
Form of shell, cylindrical, with the first three whirls equal in di- 
ameter, and from this the shell slopes to an obtuse point, forming an 
angle of sixty-five degrees. The shell is quite smooth being marked by 
some few, fine, but irregular lines of growth, which become rather 
more prominent on the upper whirl. The whirls are somewhat bulg- 
ing with the suture rather deep. 
Aperture, rather large and open, scarcely contracted within. 
The lower tooth is quite prominent, about .05 high nearly twice as 
long as high, accompanied on the left side by another tooth which is 
about half its height, yet which is as long as it, but which as it pro- 
ceeds backward, diverges from it by curving around toward the col- 
umn, thus the interior termination of the two teeth are nearly .10 
apart and considerably widened. Both teeth are set back nearly twice 
their length, from the frontal bar and taken together are about central in 
position. The upper tooth is placed well up in the column, quite behind 
the outer termination of the lower tooth, is about as high as the larger, 
but rather thinner and extends around the column. 
The margin is not produced forward beyond the diameter of the 
shell, is very slightly inclined backward and a little to one side, hut not 
much beyond the diameter of the shell ; it is thin, measuring about 
.05, is somewhat reflexed outward, about .04, and rolled over a little, 
but the edge is smooth. The frontal bar is quite well developed, and 
although it completely interrupts the striations, they can be seen 
through the translucent layer within it. 
Color of shell, externally, yellowish white, marked with undulating 
longitudinal lines of yellowish brown which are more abundant on the 
spiral whirls, where many are as wide as the white interspaces between 
them. These lines are seldom broken by horizontal encroachments of 
white. Within, pale yellowish brown, becoming white on the teeth and 
margin. 
