NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



825 



Measuremen ts.- 



Diameter of the peristome 0.12 mm. 



Interior diameter of the tubes (section) 0.06-0.08 mm. 



Maximum diameter of the branches 1.8 mm. 



Diameter of the mesopores 0.64 mm. 



Diameter of the ovicell 1.35 mm. 



Affinities. Exteriorly this species, much resembles Leiosoecia parvicella Gabb 

 and Horn, 1860, from the Cretaceous of New Jersey; it differs from it in its club- 

 shaped tubes, its hollow zoarium, and in its larger and more globular ovicell. 



Bx12 



A x12 



Cx12 



FIG. 274. Parleiosoecia, new genus. 

 A-C. Parleiosoecia jacJcsonia, new species. A. Ovicelled branch, X 12, showing the smooth 



ovicell. B. Transverse section, X 12. C. Vertical section, X 12. 

 Middle Jacksonian of South Carolina. 



It appears rather close to Heteropora subreticulata Eeuss, 1869. from the 

 Priabonian of Vicentin, but it differs from it in the exterior form of the mesopores. 

 The interior of the branches presents (fig. 13) a successive series of rather regular 

 constrictions, the utility of which is not yet known. They do not correspond to 

 the form of an internal substratum, for the branches are naturally hollow and 

 closed at their extremities. These internal cavities are often traversed by very 

 convex diaphragms (fig. 12). 



At the ramifications the walls of the mesopores cease to be vesicular, trans- 

 forming themselves thus into firmatopores or canals of reinforcement. 



Occurrence. Middle Jacksonian. Wilmington, North Carolina (rare) ; near 

 Lenuds Ferry, South Carolina (rare) ; Eutaw Springs, South Carolina (very com- 

 mon) ; 18 miles west of Wrightsville, Johnston County, Georgia (very rare) : Rich 

 Hill, 5 miles southeast of Knoxville, Crawford County, Georgia (rare) ; 17 miles 

 northeast of Hawkinsville, Georgia (very common). 



Cotypes.Cai. Nos. 65446-65451, U.S.N.M. 



