GASTROPODA. 965 
Lophospira obliqua.] 
improbable that the idea of an abrupt retral curve of the striae was received from 
some similar associated but distinct shell. That he united more than one species or 
variety under the name dicincta is shown, provided the form has been correctly 
drawn, by his figures 5g and h. In the first, representing the fossil of the natural 
size, no upper carina is shown; nor is the peripheral angle trilineate. The second 
represents a part of the last whorl magnified and shows not only one, but two 
carinz on the lower half. Perhaps these figures are not entirely trustworthy. 
Although very frequently quoted, we thought it best to restrict the synonomy 
of the species to the original description, because we found it almost impossible to 
decide in most instances whether an author had the true bicincta before him or not. 
With collectors the practice prevails to a large extent to identify almost any set of 
Lower Silurian Lophospira with the bicincta, and we have seen no less than ten 
distinct species in collections bearing the one label “Murchisonia bicincta Hall.” 
Salter’s M. bicincta (Can. Org. Rem., Dec. 1, p. 19; 1859) clearly belongs to the next 
species or variety (L. obliqua) while Meek and Worthen’s (Geol. Sur, IIl., vol iii, p. 
317; 1868) we describe as another new species under the name L. perforata. Then 
the Upper Silurian shell from the island of Gothland, which Lindstrém identifies 
with this species (he calls it a Plewrotomaria) and describes and figures so beautifully 
in his classical work on the Gastropoda (Up. Sil. Gastropoda of Gotland, p. 106, pl. 8; 
1884) is most certainly not the same as the American species. We have specimens 
of the Gothland shell before us and can say most emphatically that it has scarcely 
a single specific feature in common with L. bicincta. Comparing it with the other 
American species of Lophospira, we find that while it resembles L. swmnerensis 
Safford more than any of the others, it is still readily distinguished. 
The essential characters of L. bicincta, as here identified and restricted, are (1) 
the ventricose whorls, (2) the sharp and regular lines of growth, and (3) the exceed- 
ingly shallow sinus in the outer lip and vertical direction of the surface striz from 
the peripheral band downward. 
Formation and locality.—Trenton period, Stones River group, not uncommon in the ‘‘Central lime- 
stone” at Murfreesboro, Tennessee, and rather rare in the Vanuxemia bed at Minneapolis, Minnesota, 
Dixon, Illinois, and Beloit, Wisconsin; Black River group, Mercer county, Kentucky; Trenton group, 
Middleville, New York; Clitambonites and Fusispira beds at several localities in Goodhue county, Minne- 
sota; Cincinnati period, Richmond group, at Spring Valley and other localities in Fillmore county. 
Collection.—E. O. Ulrich. 
LopHosPirA OBLIQUA, n. sp. (Ulrich.) 
PLATE LXXII, FIGS. 6—8. 
Murchisonia bicincta SALTER, 1859, Can. Org. Rem., Dec. 1, p.19. (Not IM. bicincta HALL, 1847.) 
This form agrees in all respects with L. bicincta excepting that the surface striz 
are less sharp and not so regular, and that instead of passing vertically downward 
