GASTROPODA. 903 
Salpingostoma richmondensis.] 
verse, imbricating lamellae, seven or eight in a distance of 5mm. On the dorsal 
parts of the shell these lamelle must be much farther apart. Revoiving lines are 
faintly indicated on the back. There is something so suggestive of T'remanotus 
about this species that it is te be hoped that better specimens may soon be 
discovered. 
Formation and locality.—Richmond group of the Cincinnati period, near Spring Valley, Minnesota. 
Collection.—EK. O. Ulrich. 
SALPINGOSTOMA RICHMONDENSIS, ». sp. (Ulrich.) 
PLATE LXVII, FIGS. 39 and 40. 
Shell slightly exceeding medium size, the hight, including apertural expansion, 
50 to 55 mm.; known from casts of the interior chiefly. These consist of about three 
strong volutions, the inner ones wide, depressed, sharply rounded on the sides, 
broadly and evenly convex on the back, less convex and with a very slight central 
cavity on the ventral side, the whole giving a transversely elongate subelliptical 
cross-section, whose width is a little more than twice the hight. Dorso-ventral 
diameter of last volution increasing very rapidly in the outer half, while the trans- 
verse diameter enlarges very slowly. Just behind the apertural expansion, where 
the volution is more or less distiactly compressed laterally, the dimensions in three 
specimens (casts) are as follows: width 22, 23 and 24 mm.; hight 26, 27 and 27 mm. 
At the opposite side of the shell the volution is about 15 mm. wide and 7 mm. high 
in all three specimens. The umbilicus is of the usual size for the inner volutions, 
but for the entire shell it is comparatively small. This is because the angular or 
narrowly rounded boundary moves gradually toward the ventral side of the 
volutions, causing the wall of the umbilicus to become more and more abrupt. 
Just behind the aperture it is nearly or quite perpendicular, the ventral surface of 
the volution being almost flat. Apertural expansion abrupt, apparently not very 
wide, with recurved edges, broadly ovate in outline, slightly narrower above than 
below. Dorsal slit about 20 mm. in length, beginning the same distance or some- 
what more behind the apertural expansion. The slit is represented by a rough 
(fractured) ridge on casts. Behind it the cast is smooth, but in front of it there is a 
more or less distinct broad furrow. 
The surface markings have been observed only on the back of the second 
volution. Here they consist of about seven irregular revolving ribs on each side of 
a very narrow elevated slit-band. At intervals of about 1.5 mm, the ribs are 
interrupted by transverse lamellz. Where they are shown the volution has a 
width of 7 mm. 
