986 THE PALEONTOLOGY OF MINNESOTA. 



(.Lophospira bowdeni. 



concave to the prominent peripheral band; base at first a little concave because of 

 a low ridge a short distance beneath the band, then following the course of the 

 striae, with a concave outline to the acute basal extremity; umbilicus very small; 

 inner lip nearly vertical, twisted, and greatly produced below. Surface markings 

 very faint upon the upper side of the volutions; on the base they consist of rather 

 regular, strong, overlapping lamellae, curving strongly forward from the peripheral 

 band and, finally, running in a nearly vertical direction, and almost parallel with 

 the inner lip, to the narrow basal extremity of the aperture. 



There is no described species (of this family) known to us having the aperture 

 produced below as much or in the same manner as in this shell. A similar condition 

 is exhibited by two specimens from the Lorraine group, one from Cincinnati, the 

 other from central Kentucky, but as the apical angle is somewhat less in these (56 

 and 57) and the lower side of the volutions more ventricose, we hesitate to say that 

 they belong to the same species. The surface being abraded on them we cannot 

 say how the markings compare with those observed on the type described and figured. 



Formation and locality. Richmond group of the Cincinnati period, Hanover, Butler county, Ohio. 

 Collection. E. O. Ulrich. 



LOPHOSPIKA BOWDENI Sdfford. 

 PLATE LXXII, FIGS. 40-43. 



Murchisonia bowdeni SAFFORD, 1869, Geol. of Tenn., pi. o, flgs. 2a-2c. (Not described.) 



Hight 40 to 70 mm., usually 45 to 50 mm.; apical angle of Tennessee types of 

 species averaging about 27 but varying between the extremes of 26 and 30; of the 

 Lorraine group variety 30 to 34; of the Richmond group form 25 to 28 for 

 specimens from Trimble county, Kentucky, and 27 to 83 for those from Boyle 

 county in the same state; volutions eight to ten, moderately angular, the peripheral 

 band thick, convex, varying as to prominence, situated beneath the center of the 

 whorls; upper slope convex, sometimes obscurely carinated, in the upper half, more 

 or less concave in the lower half; lower carina obscure, never sharp, often indistin- 

 guishable, the space above it to the peripheral carina generally a little concave; a 

 minute umbilicus usually present, though in narrow specimens it is commonly 

 covered by the reflexed inner lip; aperture subtriangular or irregularly quadrate, 

 the outline depending upon the angle at which it is viewed; inner lip nearly vertical, 

 generally exhibiting a small channel in its lower part. Surface with obscure 

 undulations or unequal lines of growth. Th^se are very strongly recurved toward 

 the peripheral band, indicating a large and deep > shaped notch in the outer lip' 

 The band is distinctly convex, occasionally subangular in the middle, has obscure 

 lunuki', and is bordered on both sides by a delicate raised line. 



