10 
MONOGRAPH OP THE GENUS STROPIIIA. 
Form of shell, oblong ovate, with the first and second whirls about 
equal in diameter, then the shell slopes to a semi-obtuse point. The 
striations are numerous, forty-one to the first whirl. They are narrow, 
not wider than the interspaces, furrowed, straight, and a little inclined 
to the right. 
Aperture, nearly circular, this is about as wide as it is high. It 
is small, somewhat contracted at the entrance and measures a little more 
within than at the outer edge. The lower tooth is .12 long by '03 high , 
is about central in position and is set back about .1G from the frontal bar. 
Both the teeth behind this are about the same sizes as the central, but 
from its position the outer is longer than the inner. The upper tooth 
is about as high a3 the central and extends back around the column. 
Margin, not produced forward quite as far as the diameter of the 
shell, is considerably inclined to the left, beyond the side. It is some- 
what thickened, measuring .05, is rolled over and rounded, slightly far- 
rowed and polished, but is not flanging, there being a slight depression 
only behind it. The frontal bar is well developed, completely interrup- 
ting the striations, which, although they do not appear within it as 
prominences, may be seen through the opaque covering of the mouth. 
Color of shell externally, shining white, mottled irregularly with 
rather longitudinal patches of pale reddish brown; internally, pale brown 
becoming whiter on the teeth and margin, 
DIMENSIONS. 
Size of typical specimen .75 by .35. Largest specimen .85 by .45; 
smallest, .65 by .32. Longest specimen .85; shortest, .65. Longest 
diameter, .45; smallest, .30. 
OBSERVATIONS. 
There is but little important individual variation in the specimens 
examined, aside from size. The two back teeth vary a little, and one 
specimen of which I have made a section, has the inner much shorter 
than the outer. Another has one well defined tooth in the beginning of 
the second whirl, and another slightly developed in front of it. 
There can be no doubt but what this is the species which Fer- 
ussac had in hand when he described his Pupa striatella, for he clearly 
states that the teeth are prolonged back into the interior of the shell, as 
may be seen by his decsription given below, taken from his work cited 
at the head of this article. I have selected as a type a shell which 
closely agrees with his figure and dimensions given, namely, 20 mill, 
long by 9 mill. wide. 
