Maryland Geological Survey 335 



part of the axis; pleurae composed of 18 annulatioiis, nearly flat near the 

 axis, thence regularly depressed toward the margin, about the middle of 

 each segTuent is a furrow which begins near the axis and extends nearly 

 to the margin, while the convex portions of the segments are marked by 

 two somewhat irregularly arranged rows of tubercles, one on each side 

 of the furrow; margin scarcely shown except at the posterior extremity 

 where it is apparently terminaied by two caudal spines, which are broad 

 at their bases, separated by a rather greater distance than the width of the 

 axis, and one showing apparently the bases of three or four small spines 

 near its extremity. 



This pygidium is to be compared with those of Dalmanites (Coronura) 

 aspectans (Con.) of the Onondaga limestone of New York, Ohio and the 

 Falls of the Ohio ; but is considerably smaller than average specimens of 

 that species, while the axis is composed of a larger number of segments 

 and is marked by two longitudinal rows of tubercles instead of five. 



Length of pygidium, 13 mm. ; width, 22 mm. 



Occurrence.— 'RoMT^iEY Foemation, Hamilton Member. Ernstville 



Collection. — Maryland Geological Survey. 



Subclass EUCRUSTACEA 



Order OSTRACODA 

 Family LEPERDITIIDAE 



Genus LEPERDITIA Renault 



LepERDITIA ? SUBROTUNDA TJlrich 



Plate XLIV, Fig. 6 



Leperditia ? sutrotunda Ulrich, 1891, Jour. Cin. Soc. Nat. Hist., vol. xiii, p. 



181, pi. xvi, figs, la, b, c. 

 Leperditia ? cf. suirotunda Kindle, 1912, Bull. U. S. Geol. Surv., No. 508, p. 



115, pi. ix, fig. 7. 



Description. — " Size of left valve : Length, 0.68 mm. ; thickness, 0.21 

 mm. Carapace small, short, rounded, uniformly convex, encircled, except 

 at the strongly convex ventral edge, by a flattened border, widest in the 



