GASTROPODA. 973 
Lophospira acuminata.] 
Hall united with it. The latter, if correctly represented by Hall’s figures (loc. cit.), 
is so different that we have no hesitation in pronouncing it a distinct species. So 
far as our experience is concerned, L. perangulata is an unusually constant species. 
Our figures represent extremes of variation as exhibited in a large number of 
specimens. 
Formation and locality Stones River group, Watertown, New York; Murfreesboro, Tennessee; 
Mercer county, Kentucky; and, somewhat doubtfully, Minneapolis, Minnesota; Black River group, Pan- 
quette’s rapid, Canada. 
Collection.—E. O. Ulrich. (About 100 specimens.) 
LOPHOSPIRA ACUMINATA, 7. sp. (or var. Of PERANGULATA.) 
PLATE LXXIII, FIG. 8. 
Hight 10 mm. or less; apical angle about 42°. Volutions seven or eight, all 
contiguous; peripheral carina very prominent, trilineate, the central part of the 
band sharply angular; lower carina very strong, upper carina wanting; no umbilicus. 
Resembles and perhaps is merely a later variety of L. perangulata Hall, yet 
readily enough distinguished by its more depressed and more numerous volutions, 
especially considering that it isa smaller shell. It differs further in being relatively 
higher, the apical angle being narrower, in the greater prominence of the carine, 
and in wanting the umbilicus which is so constantly present in Hall’s species. A 
variety of L. pulchella is rather abundantly associated with this species at Spring 
Valley, Minnesota. It may be distinguished at once by its relatively strong upper 
keel, L. acuminata being without this keel. 
Formation and locality.—Richmond group, Richmond, Indiana, Blanchester, Ohio; and near Spring 
Valley, Minnesota. ; 
Collections—Geological and Naturai History Survey of Minnesota; E. O. Ulrich. 
Museum Register, No. 7383. 
LoPHOSPIRA MEDIALIS, ”. Sp. 
PLATE LXXIII, FIGS, 23—29. 
Hight 12 to 22 mm.; apical angle 58° to 70°, the average about 63°. Volutions 
six or seven, all contiguous, somewhat depressed, rounded below; upper slope nearly 
flat, generally a little concave in the outer half and gently convex toward the suture, 
occasionally convex enough to form an obscure subsutural angulation; lower carina 
becoming less distinct with age, never strong, generally quite indistinct; between it 
and the prominent peripheral carina, which carries the rounded band, the outline is 
more or less concave; umbilicus small but always present. Surface markings rather 
strong, lamellose, strongly curved backward, often gathered into undulating groups 
near the umbilicus. 
