1012 THE PALEONTOLOGY OF MINNESOTA. 



[Seelya inunduhi. 



founded on an interior cast of a rather slender shell of this genus. It is from the 

 Point Levis limestone of the Quebec group. We know of no species in the Trenton, 

 and the Cincinnati species about to be described is a very modest representative. 

 There are at least two Upper Silurian species. One of these occurs in the Niagara 

 limestone at Chicago, and was described by Meek and Worthen as Pleurotomaria 

 cyclonemoides. The other is the well known Pleurotomaria lloydii of Sowerby, 

 occurring in England and Gotland. Several good varieties or closely related species 

 are included in the European species, and one, as figured by Lindstrom, greatly 

 resembles our S. venlricosa. 



SEELYA MUNDULA, n. sp. (Ulrich.) 



PLATE LXX, FIGS. 11-12. 



Hight and width nearly equal, 10 to 13 mm.; apical angle 70 to 75; volutions four, subangu- 

 lar; band prominent, narrow, concave; upper side of whorls with a strong angulation or carina midway 

 between the band and the suture, and sometimes with a small ridge close to the suture, the intermediate 

 spaces more or less concave ; lower side convex except immediately beneath the Salient band, with two or 

 three (perhaps more) small -revolving ridges ; umbilical perforation very minute; aperture rounded, lines 

 of growth obscure. 



Remembering that the band is concave, we know of no shell in the Trenton and Cincinnati or Hud- 

 son River periods that might be confounded with this species. 



Formation and locality. Lower part of Lorraine group, Cincinnati, Ohio, and Newport, Kentucky. 

 Good specimens appear to be very rare. 



Collection. E. O. Ulrich. 



Genus HORMOTOMA, Salter. 



Murchisonia (part.) of authors. 



Hormotoma, SALTER (as subgenusof Murchisonia, D'Arch. and Vern.), 1859, Can. Org. Remains, 

 Decade 1, p. 18; CEHLBKT, 1887, Extr. Bull. Soc, d'Etud. Sci. d'Angers, p. 18. 

 Goniostropha (part.), CEHLEBT, op. cif., p. 13. 



For generic characters see page 959. 



This division of the Pleurotomariidce seems to us as in every way fully deserving 

 the rank of a distinct genus. In the first place, the species of Hormotoma have no 

 discoverable relation to the original types of Murchisonia, the genus with which 

 they have been heretofore almost universally associated. Next, the generic type 

 maintained its peculiarities through a long period of time, beginning no later than 

 the Calciferous and extending upward through the intervening beds to the top of 

 the Upper Silurian. Beyond this horizon we meet with slightly modified but 

 undeniable descendants in the lower and middle divisions of the Devonian system. 

 The latter, because they have developed a short apertural slit, should perhaps be 

 separated, in which case the somewhat inappropriate term Goniostropha might be 



