NORTH AMERICAN EARLY TERTIARY BRYOZOA. 

 PLAGIOECIA SUBRAMOSA Ulrich. 1901. 



Plate 104, Ogs. 5, 6. 



709 



1901. t'asdpora sitbraiiwsa 

 figs. 1, 2. 



ULRICH, Maryland Geological Survey, Eocene, p. 207, pi. 19, 



Description. Zoarium consisting of small flattened branches, varying from 

 subcylindrical to flabellate, usually about 1.5 mm. in thickness. Ends of branches 

 convex, occupied by the mouths of numerous subequal, thin-walled, angular tubes, 

 usually about 0.12 mm. in diameter. Sides of branches with rather obscure trans- 

 rerse wrinkles and the apertures of the true or fully developed zooecia. The latter 

 are somewhat scattered, though a tendency to arrangement in series chiefly longi- 



D 20 



A XI2 



FIG. 233. Genus Plagioccia Canu, 191S. 



A. Complete ovicellecl zoariimi. X 12, of I'lttyinccia patina Lamarck, 181C>, from tlie English 

 channel. 



B. Sketch, X 15, of Plagioecia lalomarginata D'Orbigny, 1852. (After Neviaui, 1905.) 



C. Two views, X 20, of ovicellecl portions of Plagiorcia sarniensis Norman, 1864. (After 

 Harnier, 1915.) 



tudinal is commonly apparent. Zooecial apertures ovate, about 0.14 by 0.18 mm., 

 with about five in 2 mm. Interapertural space as well as apertural covers, 

 minutely punctate. In vertical fractures the tubes are shown to be very long 

 and that they approach the surface very gradually. Ooecium. a mere inflation of the 

 surface through which one or more of the zooecial tubes pass. In the general form 

 of its zoarium this species agrees very well with F. pavonina (Michelin) , D'Orbigny's 

 type of the genus, but its zooecia are much smaller and not nearly so prominent. 



The above description by Ulrich is excellent, but Fascipora, to which he re- 

 ferred the species, is only a zoarial form and not a natural genus. Judging by the 

 ovicell, this is a very typical Plagioecia. 



Occurrence. Lowest Eocene (Bryozoan bed at base of Aquia formation) : 

 Upper Marboro, Maryland (rare). 



