Descriptions of Species. 25 



Leda (?) harveyi sp. nov. 

 Plate I, Figs. 7, 8. 



Shell minute, one-sixteenth to one-eighth of an inch in length, 

 elongate, smooth, concentrically striate; beaks situated at ante- 

 rior third, blunt, thick, and recurving ; posterior cardinal margin 

 elongate, straight, or slightly concave ; pallial margin straight or 

 slightly sinuous ; anterior cardinal margin short, straight ; ante- 

 rior margin very slightly rounded at base; posterior margin 

 angular, short, and straight; anterior half of shell thick, sub- 

 globular; posterior half elongated, rapidly thinning posteriorly, 

 and sometimes marked by a strong angular ridge extending from 

 beak to union of pallial and posterior margin ; cardinal area not 

 exposed so as to show hinge mechanism. 



This minute shell occurs in great masses, resembling small 

 black specks in a calcareous cement, which under the magnify- 

 ing glass reveals the outline shown in the figures ; the hinge 

 mechanism not seen. 



Found thus far only at the plant beds of the Paluxy, near 

 Glen Rose. 



Named in honor of Mr. J. W. Harvey, who first collected from 

 this locality, but died before the collections could be published.* 



Cucullaea gratiota Hill. 



Area gratiota Hill. Arkansas theological Survey, Annual Re- 

 port 1888, vol. IT, p. 133, plate J4rfigs. 2, 2a. Described an< 

 figured in my Arkansas Report as Area gratiota. Occurs also in 

 plant beds near Glen Rose, Texas, and in bluffs of Colorado. 



Cucullaea comanchensis sp. nov. 

 Plate III, Figs. 1, 2. 



Cordate, globose, thicker and higher than long, subquadrate 

 in lateral aspect ; posterior margin strongly truncate, pallial 

 margin gently rounded; anterior margin short and truncate; 

 exterior of cardinal area elongate and broad ; umbones small, 

 high, and incurved, but not touching; shell thick, rough, and 

 marked by strong, irregular, rugose lines ; hinge mechanism not 

 visible. 



* See American Geologist, October, 1802. 



4 BIOT,. Soc. WASH., VOT,. VIII, 1893. 



