Maryland Geological Survey 513 



Subclass EUCRUSTACEA 



Superorder OSTRACODA 

 Family LEPERDITIID/E 



Genus LEPERDITIA Renault 



Leperditia altoides Weller 



Plate XCVII, Figs. 8, 9 



Leperditia altoides Weller, 1903, Geol. Surv. N. J., Pal., vol. iii, p. 252, pi. 

 xxiii, figs. 1 and 2. 



Description. — " Carapace of medium size, obliquely subreniform, nar- 

 rower in front, somewhat variable in proportions ; valves strongly convex, 

 gibbous in the middle. Dorsal margin straight, from three-fifths to two- 

 thirds the total length; dorsal extremities obtusely angular, posterior 

 margin broadly rounded, ventral margin convex, anterior margin narrower 

 and often more sharply rounded than the posterior. Eye tubercle small, 

 but rather prominent, situated at a point about one-third the length of the 

 straight dorsal margin from its anterior end and about three-fourths of 

 the height of the valve at that point from the basal margin. Surface of 

 the valves flattened at the antero-dorsal angle, the flattening extending as 

 a narrow, indistinct, marginal border nearly to the center of the anterior 

 margin. Along the posterior margin there is a similar, narrow, indistinct, 

 flattened border, which extends from the postero-dorsal angle to a point in 

 the ventral margin directly below. Surface of valves perfectly smooth. 



" The dimensions of an average specimen are : Length 7 mm. ; height 

 4.5 mm.; convexity of one valve 1.5 mm." Weller, 1903. 



The type specimens of this species which are figured are from the 

 Decker Ferry rocks of New Jersey. In Maryland the species is quite 

 abundant at several localities. 



Occurrence. — Helderberg Formation, Keyser Member. Devil's 

 Backbone, Tonoloway. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



