NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
367 
Affinities . — The distal part of the zooecia is often wider than the proximal 
part, which gives them the aspect of a broad head. 
This species differs from the recent Emballotheca quadra, ta MacGrillivray, 1880, 
in its smaller micrometric dimensions and the entire absence of a mucro concealing 
the rimule. 
This is a magnificent species, of which only two specimens have been found. 
Occurrence . — Middle Jacksonian (Castle ITayne limestone) : Wilmington, North 
Carolina (rare). 
Holotype. — Cat. No. 64069, U.S.N.M. 
A 
Fig. 110. Genus Tetraplaria Tenison- Woods, 1878. 
A. Tetraplaria australis Tenison-Woods, 1878. Zooecia. (After MacGillivray 1895.) 
B, C. Tetraplaria (Pollaploecium) gilbert crisis Maplestone, 1909. Zoarium, X 12, and 
aperture. (After Maplestone, 1909.) 
D-F. Tetraplaria ( Arborella ) dichotoma Osburn, 1914. D. Zooecia. E. Portion of colony, 
showing mode of growth. F. Operculum. (D-F after Osburn, 1914.) 
Genus TETRAPLARIA Tenison-Woods, 1878. 
1878. Tetraplaria Tenison-Woods, On some Australian Tertiary fossil corals and Polyzoa, 
Journal and Proceedings of the Royal Society New South Wales, vol. 12. p. 61.- — 
Synonyms Pollaploecium Maplestone, 1909, and Arborella Osburn, 1914. 
The zoarium is articulated. The zooecia are arranged in pairs, back to back, 
facing four ways; the opposite pairs of two sides alternating at right angles with 
the other two. 
Genotype. — Tetraplaria australis Tenison-Woods, 1878. 
The known species of this genus are : 
Tetraplaria australis Tenison-Woods, 1878. Fossil. 
Tetraplaria ( Pollaploecium ) gilbertensis Maplestone, 1909. Recent. 
Tetraplaria ( Arborella ) dichotoma Osburn, 1914. Recent, Florida. 
Tetraplaria ( Cellaria ) schreibersi Reuss, 1869. Fossil. 
