Measurements 



NORTH AMERICAN EARLY TERTIARY BRYOZOA. 683 



measure 0.10 mm. in diameter. The mesopores are numerous and polygonal. In 

 sections the tubes are cylindrical, the walls are not vesicular. The mesopores 

 are short, regular and parietal. 



Diameter of the orifices 0.10 mm. 



Distance between the orifices 0.50 mm. 



Diameter of the branches 2.00 mm. 



Affinities. This is a very disconcerting species. The tubes are cylindrical 

 and yet the walls are not vesicular; they are simply separated by a sort of small 

 canal resulting from the disappearance of the ectocyst; this is the habitual ar- 

 rangement of the club-shaped tubes. The zoarial walls are regular as in the zoarial 

 form Petalopora. and sometimes lamellar (in transverse section) as in Hornera. 

 The mesopores are regular, parietal as in the forms Petalopora and Sparsicavea, 

 which also have the club-shaped tubes. 



This mingling of peculiar characters of the different families appears to indi- 

 cate that this species must be ovicelled. Unfortunately we have not found many 

 specimens of it. 



This species differs from Parascosoecia consimilis Ulrich, 1882, in a greater 

 diameter of the orifice (0.10 and not 0.08 mm.) in its solid and never hollow 

 branches, in its much less numerous and shorter mesopoi'es, and in its cylindrical 

 tubes. 



It differs from Parlciosoecia jacLsonica, in which the exterior aspect is identical, 

 in its solid branches, its much shorter mesopores, and its cylindrical tubes. 



Although very close to Heieroporct subreticulata Reuss, 1869. it differs from it 

 in the exterior aspect of the mesopores. which, however, do not conform to the 

 published figures. 



Occurrence. Lower Jacksonian (Moodys marl) : Jackson, Mississippi (rare). 



Middle Jacksonian: Three and one-half miles north of Grovania, Georgia 

 (rare) ; one-half mile southeast of Georgia Koalin Company's Mine, Twiggs County, 

 Georgia (rare). 



Cotypes. Cat. No. 65371, U.S.N.M. 



HETEROPORA AMOENA De Gregorio, 1890. 

 Plate 113, figs. 16-18. 



1890. Entalophora amoena DE GREGORIO, Monographie de la Faune Eocenique de 1'Alabama 

 et surtout de celle de Claiborne de 1'etage Parisien, Annales de Geologie et de 

 Paleontologie, livr. 8, p. 240, p. 39, fig. 21. 



Description. The zoarium is free, subcylindrical, hollow, ornamented with 

 large lateral and alternate apophyses > forming pseudobranches. The orifices are 

 orbicular, widely spaced, and measure 0.10 mm. in diameter. The mesopores are 

 numerous, irregular, polygonal. The tubes are cylindrical. 



Affinities. We believe that this species is Kntalophora amoena de Gregorio. 

 1890, for it has the same lateral apophyses and the same cellular surface. To be 



