966 THE PALEONTOLOGY OF MINNESOTA. 
(Lophospira concinnula. 
from the peripheral band they cross the space between the central and lower carine 
somewhat obliquely, thus indicating a deeper sinus in the outer lip. Casts of the 
interior could not be distinguished excepting perhaps those which preserve the 
aperture entire, when the difference last mentioned may serve. 
It is strange that two shells can be so very much alike and yet maintain certain 
almost minute characters so persistently as in this case. We have 42 specimens of 
the obliqua and there is never any doubt about them, the peculiarities mentioned 
being very constant. 
Formation and locality.—Rare in the upper partof the Stones River group, at High Bridge, Kentucky; 
more common in the Black River and Trenton groups at various points in Mercer county, Kentucky. 
Collection.—E. O. Ulrich. 
LoPHOSPIRA CONCINNULA, 7%. Sp. 
PLATE LXXII, FIGS. 16-19. 
Hight usually 10 to 15 mm., in one case reaching 21 mm.; apical angle 52° to 59°. 
Volutions six or seven, angular, not ventricose; upper central and lower carine all 
strong. Lines of growth fine, sharp, thread-like, regular, almost vertical beneath 
the peripheral band, and but little curved backward above it. In the grooves 
between the lines there are numerous short connecting bars, producing a minutely 
cancellated appearance. 
The peripheral band and surface markings, excepting the delicate connecting 
bars, are precisely as in L. bicincta, and we are satisfied that the new species is 
closely related to that shell, if indeed it is really not merely a variety of it. Still, 
the connecting bars are a feature deserving some recognition, and when we add that 
the volutions in L. concinnula increases less rapidly and that they are less ventricose 
and more angular, because of the greater prominence of the spiral carine, it seems 
to us that a specific distinction must be conceded. 
We describe three other species, L. pulchella, L. spironema and L. tenuistriata, 
which, if the aperture is imperfect and the surface markings abraded, it would be 
quite impossible to distinguish from each other and from L. concinnula. With any 
part of the exterior layer of the shell preserved the difficulties vanish, the first 
named three forms having a deep sinus in the outer lip and, therefore, strongly 
recurved lines of growth, while in L. concinnula the retral curvature is, as in L. 
bicincta, very slight indeed. The character of the transverse striz also is different, 
being stronger and sharper in L. concinnula. For other differences see descriptions 
of the species mentioned. 
Formation and locality— Black River group, Ctenodonta bed, Minneapolis and Cannon Falls, 
Minnesota. 
Collections. —H. O, Ulrich (9 specimens); W. H. Scofield (1 specimen). 
