GASTROPODA. 1005 
Eotomaria elevata.] 
Horomaria ELEVATA, 7. sp. (Ulrich.) 
PLATE LXX, FIGS. 68-69. 
Shell resembling Lophospira; width 15 mm.; hight about 20 mm.; hight of aperture about 12 mm. 
apical angle 74°; volutions four or five, the last comprising much the greater part of the shell, slightly; 
? 
turretted, the upper slope nearly fiat; band slightly concave, the outer border forming the angular 
periphery of the whorls, the inner border consisting of a sharply elevated thin line; band very wide, occupy- 
ing nearly two-fifths of the sloping space between the periphery and suture ; base large, its surface moder- 
ately convex, with a slightly concave band a short distance beneath the periphery; aperture obliquely sub- 
quadrate or subtriangular, narrow below, the hight greater by a fifth or a sixth than the width ; columellar 
lip thick, reflexed, almost entirely covering the minute umbilicus; surface marked distinctly though 
rather irregularly with lines of growth, strongly recurved above, more gently below; lunul of band uni- 
formly curved, unequal, occasionally strong. 
The fact that the band is placed wholly above instead of on the periphery of the whorls, distin- 
guishes this peculiar shell at once from Lophospira, several species of which it resembles in form. The 
great width of the band may suggest relations to Omospira, but the uniform curvature of the lunulsz 
proves that the species belongs to the Pleurotomartide and not to the Raphistomide: In placing the 
species under Hotomaria we have been guided principally by the position of the band. 
Formation and locality.—Upper part of the Trenton group, Hartsville, Tennessee. 
Collection.—E. O, Ulrich. 
Genus CLATHROSPIRA, n. gen. 
Plewrotomaria (part.) of numerous American and European authors. 
For generic characters see page 954. 
In this genus we propose to include subconical or turbinate shells differing from 
Eotomaria in having a delicate cancellated surface sculpture and the band, which is 
of the concave type, placed vertically and directly upon the periphery of the whorls 
The outer lip is merely notched, not slit as in Plewrotomaria and similar genera 
The group is represented by at least three species, two of them new, in Lower 
Silurian strata of America, and by four—possibly six—European species that Lind- 
str6m has described from the Upper Silurian rocks of the island of Gotland, under 
the following names: Pleurotomaria claustrata, P. glandiformis, P. hindei, P. latezonata, 
P. gradata and P. scutulata. The last two of these six species, though agreeing in 
most respects very well with P/. subconica Hall, the type of the proposed genus, are 
peculiar in having a pair of thin elevated lines just above the center of the slit-band. 
The significance of these lines is not clear at present, but we suspect that they 
represent homologically the median line of the band of Lophospira bicincta, and if 
that is a fact, then the species in question cannot belong to Clathrospira, for this 
genus and Lophospira are widely distinct genetically. 
As near as we could learn, all of these Gotland species agree with the American 
species in having no slit. All differ, however, in having the anteriorly curved 
portion of the lines of growth just beneath the band much shorter and the anterior 
outline of the lower lip, as seen in a view of the base, much straighter. But this 
