NORTH AMERICAN EAELY TERTIARY BRYOZOA. 



319 



Affinities. The aspect of this species is that of a worn zoarium, thus recalling 

 Heteropora. The examination of the transverse section indicates clearly a Cheilos : 

 tome despite this deceptive appearance. The ascopore is not regularly placed and 

 it is often little discernible as in Acropont mamillata D'Archiac, 1846; it differs 

 from the latter species in the absence of a salient peristome. 



E 



FIG. 90. Genus Acropora Reuss, 1S69. 



A-E. Acropora gracilis Milne-Edwards, 1836. A. Zooecia. (After Milue-Ethvards, 1830.) 

 B. Zooecia and avicularia. (After Hiucks, 1881.) C. Zoaria, natural size. D. Operculum, X 

 140. E. Longitudinal section. (C-E after Levinsen, 1909.) 



F-K. Acropora coronata Reuss, 1S69. F, G, H. Three views of zooecia, showing variations 

 of the avicularia, X 95. I. Termination of a branch, natural size, and X 12 showing openings 

 for articular tubes. J. Small form (cf, Acropora labrosa Reuss). K. Diagrammatic section 

 through a zooeciurn; asc, ascopore; op, operculum; <&, tubules. (F-K after Waters, 1891.) 



Occurrence. Midwayan (Clayton limestone) : One mile west of Fort Gaines, 

 Georgia (rare). 



Cotypes.G&i. No. 63817, U.S.N.M. 



ACROPORA SAILLANS, new species. 



Plate 85, figs. 4-12. 



Description. The zoarium is free, cylindrical, bifurcated, formed of 5 or 6 

 longitudinal rows of zooecia. The zooecia are distinct, large, elliptical ; the frontal 



