426 SYSTEMATIC PALEONTOLOGY 



mately final stage. At present, however, we cannot suggest a more 

 natural arrangement, the species with which it seems to agree best 

 being now classified under Lepralia. Of these L. lahiosa and L. sub- 

 plana Ulrich, from the Eocene of this state, are perhaps the nearest. 

 In both species, however, the zooecia are shorter and have a flatter and 

 Jess coarsely punctate surface. 



Occurrence. — St. Mary^s Formation. Cove Point. 



Collection. — Maryland Geological Survey. 



Lepralia (?) reversa n. sp. 

 Plate CXIII, Figs. 1, 2. 



Description. — Zoarium forming parasitic patches, several centimeters 

 in diameter and composed of a single layer, on shells. Zooecia oblong 

 quadrate or subhexagonal, generally arranged in rather regular longitud- 

 inal and diagonally intersecting rows, each about 0.-5 mm. in length 

 and 0.3 mm. in width. Orifice rather large, rounded-quadrate, enclosed 

 by a peristome of moderate thickness and elevation. Peristomes divided 

 into two jDarts, anterior and posterior, the former either straight or 

 slightly arcuate and not so prominent as the horseshoe-shaped portion 

 enclosing the sides and proximal margins of the orifice. Distal ex- 

 tremities of the latter portion of the peristome often a little thickened 

 and projecting slightly inM^ard. Just behind the proximal border of 

 the orifice there is constantly a rather small but prominently elevated 

 and thick-walled avicularium, opening ol)liquely forward. Kemainder 

 of front of zooecia with from one to three rows of large pores. Fre- 

 quently adjoining zooecia are separated by a thin raised line. Ovicells 

 moderately convex, rather large, with a central pore and one or two 

 somewhat radially disposed marginal rows of smaller pores. When 

 broken they leave a sharply defined concave space in front of the orifice, 

 slightly exceeding the latter in size. 



The division of the peristome into two parts as described is unusual 

 and produces the ])rol)ably false appearance of a reversal of the ends of 

 the operculum that has suggested the specific name. If it could be 

 proved that the hinge of the operculum was really on the distal side of 



