206 POTTSVILLE FAUNA OF OHIO 



Leda meekana Mark 

 PL X, figs. 25, 26 



1866 Nucula kazanensis. Geinitz, Die Garb, und Dyas in Nebraska, p. 20, Tab. 1, 



Figs. 33, 34. (Non N. kazanensis de Verneuil, 1845.) 



Nebraska City, Nebraska. 

 1872 Nucula bellistriata var. attenuata. Meek, U. S. Geol. Surv. Nebraska, p. 206, 



PI. 10, Figs, lla, b. 



Upper Coal Measures: Nebraska City, Nebraska; Leaven worth, Kansas; 



Iowa; Illinois. 

 1913 Leda meekana. Mark, Geol. Surv. Ohio, Fourth Ser., Bull. 17, p. 307, PI. XV, 



Fig. 1. 



Portersville limestone: Muskingum and Perry counties. 



Remarks. Leda meekana is associated in the middle and upper 

 Potts ville formation with L. bellistriata which it resembles in general 

 appearance, but differs in being more slender with the posterior portion 

 more attenuated. The species is rare. 



Dimensions. A specimen of average size measures: length 9.5 mm., 

 height 4.7 mm., thickness 2 mm. 



Horizon and locality. Lower Mercer limestone : Muskingum 

 County, Localities 38 (r), 43 (c), 45 (c); Licking County, Localities 46, 

 48, r. McArthur member: Vin ton County, Locality 84, r. 



Leda prolongata n. sp. 

 PL X,. figs. 28, 29 



Description. Shell large for specimens of this genus, elongate- 

 ovate in outline with the posterior end greatly produced; depressed 

 convex, the greatest convexity being in the anterior part below the 

 umbones but becoming gradually and regularly less to the posterior 

 tip. Beaks prominent and incurved, situated from one-third to one- 

 fourth the length of the valve from the anterior margin; cardinal margin 

 posterior to beaks strongly concave; anterior margin rounded and 

 curving regularly into the rounded base; posterior portion slender, 

 tapering to a sharp point, and greatly extended; umbonal ridge promi- 

 nent and elevated. Surface of shell marked by very fine, regular, 

 rounded concentric lines. 



Dimensions. The holotype from the Lower Mercer limestone 

 measures: length 39 mm., height 16 mm., convexity of right valve 2.5 

 mm. (compressed) ; a single small individual from the Boggs limestone 

 measures: length 22.5+ mm., height 9.5 mm., convexity 2.5 mm. 



Remarks. This species is characterized by its large size, its 

 slender form, and its greatly extended posterior portion. It is very 

 rare and is represented in the Potts ville collections by only two indi- 



