1002 THE PALEONTOLOGY OF MINNESOTA. 



[Eotomarla canallfera. 



age of the Trenton period, and three occur in Minnesota, while the others are 

 so far known only from localities in Tennessee.* These species exhibit considerable 

 variety in the form of the lower lip. In E. vicina U. and S., and E. dryope Billings 

 sp., the outline of this portion of the apertural margin is comparatively straight, the 

 outer half being less curved and produced than in E. canalifera Ulrich, and very 

 much less than in E>. supracingulata Billings sp. The last species reminds one very 



^r 



strongly of the L. mundula section of Liospira, At first we believed that the several 

 species which group themselves about L. mundula, together with E. supracingulata, 

 should be viewed as a distinct genus. A reconsideration, however, seemed to show 

 that such a course would scarcely be justifiable at present, first, because the mundula 

 group is closely connected with the more typical species of Liospira by L. progne 

 Billings and L. subconcava Ulrich, and second, because the species supracingulata 

 differs decidedly from the others in having a concave band. The latter reason 

 decided the question, since, with our present knowledge, we cannot admit that 

 concave-banded species are congeneric with convex-banded forms. For further 

 remarks on the L. mundula group of species see page 994. 



EOTOMAEIA CANALIFEEA, H. Sp. (Ulrich.) 

 PLATE LXIX, PIGS. 0-14. 



Width 15 to 30 mm.; bight about two-thirds of the width, in young examples relatively greater 

 than in old ; apical angle 80 to 85 for the first three or four whorls, the following whorls spread- 

 ing more rapidly and in some cases bringing the angle of the entire shell to 100 ; volutions five to six and 

 a half in number. 



Shell subconical, moderately convex below, with a very small umbilicus and distinct yet not deep 

 sutures. Band concave, sharply defined, channel-like, its outer border slightly overhanging the suture 

 and forming the sharply angular periphery of the whorls, the inner border strongly defined, elevated, its 

 prominence increasing with the growth of the shell. The contour of the upper surface of the whorls 

 changes considerably with growth. The apical whorl has not been observed, but the second and third 

 are nearly flat and the fourth very gently convex, while in the fifth and succeeding turns a furrow lust 

 within the band gradually widens and deepens until at least two-thirds of the space between the band 

 and suture is distinctly concave. (The specimens illustrated on plate LXIX are not sufficiently devel- 

 oped to show the last of these changes satisfactorily). Aperture subrhomboidal, a little wider than high ; 

 inner lip oblique, not very thick. Lines of growth rather unequal, never strong, very fine on the upper 

 turns. On the upper surface they are strongly recurved, indicating a deep notch in the aperture. Beneath 

 the periphery they first curve forward but soon, and rather abruptly, turn backward and finally forward 

 again as they descend into the umbilicus. Lunulas of band very delicate, rarely preserved. 



Formation and locality. Stones River group ("Central limestone") near Murfreesboro, Tennessee. 

 Collections. Prof. J. M. Safford ; E. O. Ulrich. 



We suspect that two or three other species described by Billings and Hall will prove to belong to Eotomaria, but MS 

 our efforts to see the original types have failed, and as the published descriptions and Illustrations are too Indefinite to 

 admit of certainty, we have thought it best to postpone their consideration. 



