410 SYSTEMATIC PALEOXTOLOGY 



out its more intimate alliances. Possibly it may fall under Canu's sub- 

 genus Rhijncliotella, but not without considerable modification of his 

 definition. An undescribed species occurring in the Cretaceous of New 

 Jersey is nearer than any other known to us. 



Occurrence. — Choptank Formatiox. Jones Wharf. 



Collection. — Maryland Geological Survey. 



Membranipora germana n. sp. 

 Plate CXI, Pigs. 8, 9. 



Description. — Zoarium forming a delicate crust upon foreign bodies, 

 the largest seen being less than 1 cm. in diameter. Zooecia shallow, 

 arranged in curved radiating lines in which about 6 occur in 3 mm.; 

 measuring transversely, 11 to 12 of the rows in the same space. Opesia 

 large, more or less elongate-ovate, the length and width usually as 3 is 

 to 2, separated laterally from their neighbors by about half their width , 

 enclosed by a ring-like thickening formed by a furrow separating adjoin- 

 ing zooecia. At somewhat irregular intervals, the interzooecial space 

 widens and is occupied by a rounded cell that may have lodged some kind 

 of avicularium. These cells vary greatly in size but are always consider- 

 ably smaller than the true zooecia. Occasionally the front margin of 

 the zooecium is more elevated than the rest of the circumference. No 

 ovicells observed. 



This species is probably closely related to M. pleheia Gabb and Horn 

 from the Cretaceous of New Jersey, the two having zooecia very similar 

 in shape and size but the older species exhibits a well marked difference 

 in its numerous and equal sized interzooecial pores ( ? avicularia) . There 

 are several European fossil species and living forms with which it might 

 be compared but none matches it exactly. 



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

 Formation. Dover Bridge. 



Collection. — Maryland Geological Survey. 



Membranipora parvula n. sp. 

 Plate CXI, Figs. 1, 2. 



Description. — In its general zoarial and zooecial characters this species 

 resembles M. germana and M. pleheia Gabb and Horn, but it is readily 



