GASTROPODA. 995 
Liospira abrupta.] 
though somewhat obliquely, nearly twice as much of it being visible in a view of the upper side than is 
seen ina basal view. It is to be distinguished only on the best specimens, but we have at least fifty 
before us showing it very clearly. The inner lip is almost vertical in the Trenton variety of the species 
and always more nearly so than in the Utica form. 
This species rarely, if ever, exceeds 16 mm. in diameter, the average for most localities being 11 or 
12mm. The Maquoketa shales types are commonly less than 10 mm. in diameter. Aside from the fact 
that it is considerably smaller there is little to distinguish LZ. micula from L. progne Billings sp. They 
are doubtless closely related species. 
Formation and locality.—Trenton group, Burgin, Danville and Frankfort, Kentucky; Utica group 
(Maquoketa shales) at various localities in Minnesota, Wisconsin, Illinois and Iowa, associated with 
Ctenodonta fecunda; also in Ohio and Kentucky, where there is reason to believe that it ascends into the 
Lorraine group. 
Collection.—H. O. Ulrich. 
LiosPIRA ABRUPTA, 7. Sp. 
PLATE LXXXII, FIGS, 36-88. 
A small species like the preceding but with the spire relatively less elevated and not entirely 
smooth at the sutures, the outer edges of the inner whorls projecting just enough to be noticed readily 
by the naked eye. The band is also more distinct, especially upon the upper side where it reminds one 
considerably of the concave band of an Hotomaria; then it is also sharper on the edge, while the lower 
half of the band is usually much more distinct. The umbilicus is not filled but extends-up to the 
apical whorl, showing all the whorls within; its edge is sharply angular, the sides nearly vertical, while 
its width equals something like a fourth of the greatest diameter of the shell. The base is a trifie 
higher than the spire, the basal slope, from the periphery to the edge of the umbilicus, gently convex; 
the aperture is triangular, its width slightly exceeding the hight. Aside from the peripheral band, the 
surface appears to have been-without markings of any kind. There are four whorls without counting 
the minute nucleus. 
The largest of four specimens from Minnesota, belonging to this or a closely related species, has 
a width of 8.5mm. The width in about one hundred specimens from Tennessee varies from 7 to 10 mm., 
and in nine-tenths of thesé from 8to 9mm. The Minnesota specimens doubtfully referred here differ from 
_ the Tennnesee and Kentucky types of the species in the more rapid expansion of the whorls, three sufficing 
where it requires four in the latter, and in having a relatively higher spire. In both of these points 
they agree with LZ. micula Hall sp., and we would refer them to that species were it not that they have 
an open umbilicus. 
Formation and locality—Stones River group, Murfreesboro, Tennessee; High Bridge, Kentucky. 
Two of the Minnesota specimens referred to are from the limestone at Minneapolis, the others from 
the Black River shales at Chatfield. 
Collection.—E. O. Ulrich. 
Liospira viTruvia Billings. 
PLATE LXIX, FIGS. 3—8. 
Pleurotomaria vitruvia BILLINGS, 1865, Pal. Foss., vol. 1, p. 171. 
Pleurotomaria (or Raphistoma) lenticularis (part.) of numerous American authors. 
Specimens of this well marked species are not known to exceed 30 mm. in diameter, a good average 
being about 25 mm. The hight is about half of the width. The upper side of the last whorl is 
frequently a little concave because of a slight elevation of the peripheral band. The umbilicus is open 
but varies somewhat in size, its width being often not more than a fourth, at other times quite 
a third of the greatest diameter of the shell. The principal peculiarities of the species occur on the 
under side. Here we have first the open umbilicus with its angular margin and flattened sides; and 
