1000 THE PALEONTOLOGY OF MINNESOTA. 



[Llospira angulata. 



smaller and deeper umbilical depression. From Helicotoma larvata Salter, with which it is associated in 

 the Black River group of Canada, it is distinguished by having a more obtuse periphery and the umbilicus 

 not only a trifle smaller but also covered entirely by the reflection of the inner lip. In H. larvata, which 

 may belong to Liospira, the umbilicus is open, angularly outlined, and exposes all the whorls. 



Formation and locality. Black River group, Pauquettes Rapids, Ottawa River, Canada; lower part 

 of Trenton group, Mercer county, Kentucky; upper beds of same near Danville, Kentucky. 



Collection. E. O. Ulrich. 



LIOSPIRA ANGULATA, n. sp., (Ulrich.) 



PLATE LXIX, FIGS. 42-46. 



Hight and width respectively as five is to eight or nine. Average width about 15 mm. Width of 

 the largest of thirty specimens 17 mm. Whorls slender, about five in number on the upper side, with a 

 slightly elevated peripheral edge, concave within this and convex in the inner third. This convexity and 

 the raised edge of the whorl next within produces a deeper suture line than in any other species of the genus 

 known. Periphery obtuse, nearly vertical beneath the slit-band; base convex to the angular edge of the 

 umbilicus. The latter slopes rapidly without being vertical, exhibits all the whorls within, and as a rule 

 makes up about one-third of the width of the shell. Aperture subpentagonal; anterior outline of lower 

 half of peristome not very strongly bowed forward, the inner extremity of the upper lip extending slightly 

 beyond it. 



This species seemed at first to be the same as L. numeria, described by Billings as a Pkurotomaria 

 from division G of the Quebec group of Newfoundland. A second and more careful comparison, however, 

 brought out at least one difference upon which to base a separation. Namely, the upper side of the 

 whorls is said to be " nearly flat or gently concave " in L. numeria, and Billings' figure (Pal. Foss., vol. i, 

 p. 229, fig. 213a) shows that this concavity extends inward quite to the suture. His description, which 

 would almost certainly do so if anything of the kind occurred in the Newfoundland shell, makes no 

 mention of a ridge-like convexity in the inner third like that which occurs here in L. angulata not only on 

 the exterior but on casts of the interior as well. 



Formation and locality. In cherty layers of the Black River group, Mercer county, Kentucky. 

 Collection. B. O. Ulrich. 



Genus EOTOMARIA, n. gen. 



In part Pkurotomaria and Eaphistoma of American authors. 



For generic characters see page 954. 



Restricting Pleurotomaria to species agreeing closely with the original type of 

 the genus, P. anglica, we find that it is characterized (1) by a long slit, (2) the supra- 

 peripheral position of the band, (3) the posterior direction of the outer lip beneath 

 the band, and (4) the coarsely nodose and longitudinally striated surface of the 

 whorls. In Eotomaria there is a notch in the outer lip merely and no slit, one edge 

 of the band, the lower, forms the periphery of the whorls, the lines of growth curve 

 more or less forward beneath the band and the surface is marked by simple lines of 

 growth only. Raphistoma, as we have shown on preceding pages, is a totally 

 different type of shell, being without not only slit but a band as well, while the lines 

 of growth, which of course indicate the outlines of the lip, follow a simple or double 

 sigmoid curve in crossing the flat upper side of the whorls. 



