990 THE PALEONTOLOGY OF MINNESOTA. 
{Lophospira (?) trochonemoides, 
which the lines of growth are recurved is comparatively thin and sharp with the lines continuing without 
interruption over the summit. (See pl. LX XVII, fig. 38.) In the Trochonemoides section of Lophospira 
on the other hand, the angle at the end of which we find the notch, is thick and carries a true pleuroto- 
marian band of which it is probably unnecessary to say that it interrupts the continuity of the lines 
of growth. : 
Phanerotrema, proposed by Fischer for species of the type of Pleurotomaria labrosa Hall, also reminds 
one in a general way very strongly of these shells. That the latter have a large umbilicus and P. labrosa 
none, is probably not of much consequence, but there are other differences that doubtless are of greater 
importance. Of these we will point out only one, namely, the long apertural slit which occurs in Phaner- 
otrema and is wanting in Lophospira, and which of itself is considered sufficient to warrant a generic 
separation. 
Formation and locality—Lower part of Trenton period (?Chazy) near Knoxville, Tennessee. We 
owe the opportunity of describing this as well as the following two equally interesting species to their 
discoverer, Prof. J. M. Safford. 
LopHospira (?) TROCHONEMOIDES, 7. sp. (Ulrich.) 
PLATE LXV, FIGS. 41—44, 
Hight 22 mm.; width 23 or 24 mm.; apical angle 100°; volutions four and a half; general appearance 
of shell decidedly like Trochonema bellula Ulrich. Upper peripheral carina thick, rounded, lower carina 
moderately distinct and sharp except on the latter half of the last whorl on which it grows gradually 
weaker until at the aperture it is quite obsolete; outer two-thirds of upper slope distinctly concave, 
remaining third flat to the suture; umbilicus large, only moderately steep, at first sharply outlined by a 
ridge which gradually becomes indistinct and at the same time moves outward causing the slope to the 
bottom of the umbilicus to become proportionally more gentle. Surface markings and aperture about as 
in L. knoavillensis, from which the present species is distinguished by its smaller size, more slowly enlarg- 
ing volutions, relatively larger umbilicus and by the upper carina which is wanting in that species. 
As L. trochonemoides occurs at the same locality and geological horizon as Trochonema bellula, and as 
the two might very easily be confounded by persons not thoroughly accustomed to separating fossil Gastro- 
poda it may be well to point out some of the differences. First, both the lower peripheral and umbilical 
caring are stronger and more persistent in the Trochonema; then the space between the upper carina and the 
suture line is concave instead of flat; finally, the upper of the peripheral carinze is not so thick and 
sharper than it isin the Lophospira, while the lines of growth, since there is no slit-band, pass over its 
summit without interruption. 
Formation and locality.—‘* Central limestone” of the Stones River group, Murfreesboro, Tennessee. 
LopHospira (?) NoTABILIs, . sp. (Ulrich.) 
PLATE LXXII, FIGS. 33—35. 
Hight and width nearly equal, a full growa specimen measuring about 27 mm., a small one 19 mm.; 
apical angle about 87°; volutions five. Shell like that of a Trochonema, with a moderate umbilicus, oblique 
aperture, and strongly carinated whorls, the last partly free in old specimens. Upper carina very strong 
and prominent, situated midway between the suture and slit-band; lower peripheral carina also unusually 
strong and prominent; midway between these carine, and separated from them by concave spaces but 
little wider than itself, is the broad and salient slit-band, composed of comparatively distant, convex 
imbricating lamellw, averaging on the last whorl about seven inl0 mm. The top of the whorls (i. e. the 
space between the suture and the upper carina) is flat and the base moderately ventricose with an obscure 
carination around the umbilical depression, The aperture is oblique, more rounded than angular, and 
abruptly notched at the extremity of the slit-band; the peristome is entire, the lower portion thick. The 
surface markings consist of rather coarse and irregular lines of growth. These, in crossing the whorls 
from above downwards, are not much recurved until just before they reach the slit-band. On the concave 
