GASTROPODA. 985 
Lophospira perlamellosa.] 
section, nearly equal. In internal casts of old shells the peripheral or central 
angle is sharp and prominent on the lower turns only, while it is nearly obsolete on 
the upper ones; last whorl exhibiting a well-marked lower angle between which 
and the peripheral carina there is a broad concave band, while the under side, 
between the lower angle and the relatively large and abrupt umbilicus, is only 
slightly convex; in the middle of the basal space the cast exhibits an obscurely 
“defined line; upper slope gently concave or flat, except near the suture where the 
internal cast is slightly convex. The matrix shows that there was a thin upper 
carina on the shell. Surface markings but faintly indicated by the specimens at 
hand, but it is certain that they curved backward strongly as in L. perangulata, 
while it is probable that they agreed in other respects also with those marking that 
species. 
The umbilicus is larger in this species than in any of genus previously described. 
In other respects it resembles L. pulchella very closely, though a much larger shell. 
L, fillmorensis, though considerably smaller and without an umbilicus, will strike 
the ordinary observer as even more like it. Butif good specimens can be compared 
it will be noticed that the lines of growth on the concave band beneath the 
peripheral angle of L. fillmorensis are but little oblique and nearly straight instead 
of strongly curved backward—in short that that shell belongs near L. bicincta, while 
L. perforata is one of the group of which L. perangulata is typical. 
We have before us the original type used by Meek and Worthen. After clearing 
it of the matrix we found that it has at least one more whorl than stated by them, 
and that the apical angle instead of being 55° is not more than 50°. The last whorl 
of the specimen is crushed in such a manner that the angle has been increased at 
least 5° beyond the normal. An examination of the matrix proved further that the 
shell really has an upper carina. Finally, it is clear that the umbilicus was not 
filled, as they supposed, by the columella. That it was not is conclusively shown by 
the core of limestone occupying all the cavity save a narrow space between it and 
the cast of the interior of the whorls which represents the space originally occupied 
by the walls of the shell. 
Formation and locality—Trenton group, Jo Daviess and Carroll counties, Illinois. We refer here 
two small casts from the Fusispira bed near Fountain, Minnesota. 
Collections.—Illinois State Museum; H..O. Ulrich. 
LoPHOSPIRA PERLAMELLOSA, 7. sp. (Ulrich.) 
PLATE LXXIII, FIGS. 55 and 56. 
Hight 18 mm.; greatest width about 10 mm.; apical angle 65°. Spire subconical, 
yolutions about five, angular; upper side first gently convex and then slightly 
