638 THE PALEONTOLOGY OK MINNESOTA. 



CLeperdltelhi m;u'r:i. 



is a very distinct species, there is probably not much danger of confusion between 

 them. 



Formation and locality. Middle third of the Trenton shales, Minneapolis, Minnesota. 



LEPERDITELLA MACRA, n. sp. 



PLATE XLIII. FIGS. 7-U. 



SI/.E. V E. C.) Length 1.4 mm ., night 1.08 mm.; thickness 0.55 mm. 



Carapace short, scarcely oblique, subovate; dorsal margin straight, four-fifths of 

 entire length of carapace, angles distinct; ends subequal, rounding almost uniformly 

 into the basal outline; carapace moderately convex except in the anterior third, which 

 is strongly compressed, giving a very unusual ventral and dorsal profile; anterior 

 edges thickened, ventral overlap strong; surface smooth. 



This species is remarkable for its compressed anterior part, and for its short 

 form, in neither of which features it is equalled by any leperditoid ostracode known 

 to me. 



Formation and locality. Middle third of the Trenton shales, Minneapolis, Minnesota. 



LEPERDITELLA QERMANA Ulricli. 



PLATE XLV. FIGS. 24-26. 



Lepertlit in gemmim UI.KICII, !Wi2. American Geologist, vol. x, p. 2(i(>. 

 SI/.K. (L. V.) Length 2.17 mm.; bight 1.4 mm.: thickness 0.67 mm. 



Carapace subovale, ends nearly equal, the posterior somewhat the wider; back 

 straight for about four-fifths of the entire length, dorsal angles well marked; ventral 

 outline somewhat oblique, most prominent just behind the center; edges rather blunt, 

 with a narrow groove or rim along the free margins of the left and perhaps of both 

 valves. Surface with the greatest convexity in the posterior half, and a broad, 

 undefined depression in front of the center of the dorsal slope. 



This form is closely related to L. mundula and L. in/lata, two species from the 

 lower division of the Birdseye limestone in Kentucky. From the first it differs in 

 having the ends more equal, the edges blunter, and the surface more convex in the 

 dorsal half. The narrow marginal rim is wanting in that species, and instead of a 

 simple dorsal depression, that form has a low elevation in the lower part of it. The 

 second differs chiefly in the greater inflation of the posterior half of its dorsal region. 



<m<l /oc/i'y.--Tliis specie-; lias so far been met with only in the Lower Blue limestone of 

 the Trentnn ill Mineral Point. Wisconsin, and Dixon. Illinois, but we know of no reason why it should not 

 occur al-u at Minneapolis :m <| other localities in the *tate. 



