416 SYSTEMATIC PALEONTOLOGY 



respectively as three is to two, arranged in rather irregular diagonally 

 intersecting series, along which about five may be counted in the space of 

 2.0 mm. The arrangement of the cells is more irregular in zoaria con- 

 taining numerous ovicells, and the upper surface of the zooecia is often 

 nearly flat, and always less convex than in specimens having few or no 

 ovicells. Upper or front wall of zooecia abundantly and rather coarsely 

 punctate. Orifice somewhat transverse, with the posterior angles 

 rounded, enclosed by a thickened border, semielliptical in outline, its 

 proximal side nearly straight, the distal portion curved and carrying 

 seven or eight minute hollow granules or spines. Immediately behind 

 the proximal border is a pore, usually elliptical, and also enclosed by a 

 thickened border. Avicularia large, acuminate ovate, with an elevated 

 border and divided into two portions by a delicate septum; usually one to 

 each zocecium and situated nearly always near either the right or the 

 left lateral angle. Ovicells large, prominently convex, punctate. 



This is probably one of the ancestors of the living type of the genus, 

 M. ciliata, but is readily distinguished by its cribrose instead of granulose 

 zooecia. Lepralia ijleuropora and L. inamosna Eeuss from the Miocene 

 of Austria, are both closely allied, but have smaller avicularia and ovicells. 



Occurrence. — St. Mary's Formation. Cove Point. Choptank For- 

 mation. Jones Wharf. 



Collection. — Maryland Geological Survey. 



MiCROPORELLA INFLATA n. Sp. 



Plate CX, Fig. 7. 



Description. — This species agrees in its more essential features closely 

 with M. prceciliata excepting that the surface appears smooth, the ovicells 

 even more inflated, the orifice set more obliquely in the front slope and 

 its border less thickened and without oral spines, the pore behind it set 

 further back and more elevated, and the avicularia smaller. The size of 

 the zocecia also is a trifle less. Under favorable light a faint reticulation 

 of the surface of the zooecia and ovicells may be detected. We know of 

 no other species near enough to require comparison. 



Occurrence. — Choptank Formation. Jones Wharf. 



Collection. — Maryland Geological Survey. 



