Measurements. 



NORTH AMERICAN EARLY TERTIARY BRYOZOA. 819 



1852. Unicavea grignonensis D'OHHIGNY, Paleoutologie frangaise, Terrains cretacf, Bryozo- 



aires, p. 971. 



1S52. Discocavca parnensis D'ORBINOY, Palexmtologie fraugnise, Cryozoaires, p. 958. 

 1852. Radiotublgcra grignonensis D'ORBIGNY, Palontologie frangaise, p. 756. 

 1852. Discocavea crispa D'OBBIGNY, Paleontologie frangaise, p. 958. 

 18S6. DiscoporcUa grignonensis FERGENS and MEUNIER, Les Bryozoaires du SystSme 



Montieu, Louvain, p. 14. 

 1909. Lichenopora grignonensis CANU, Bryozoaires tertiares des environs de Paris, Annales 



de Paleontologie, vol. 5, p. 134, pi. 17, figs. 3-7. 



Description. The zoarium is simple, free, and cliscoidal or composite incrust- 

 ing, formed of a lamella with adjacent subcolonies. The basal lamella is thick and 

 striated concentrically. The central area is large and concave. The fascicles are 

 salient, solely in the vicinity of the central area; they are uniserial, short, and never 

 reach the zoarial margins. The tubes are small, recumbent, provided with a visor; 

 the}' are arranged in quincunx in the vicinity of the zoarial margins. The cancelli 

 are polygonal and small. The ovicell placed in the central area covers over the 



cancelli. 



Diameter of the cancelli 0.06-0.10 mm. 



Diameter of the tubes 0.10 mm. 



Maximum diameter of the simple zoaria 0.75 mm. 



Affinities. This species is evidently the Lichenopora Mspida Fleming, 1828, 

 universally distributed throughout all the seas of the globe. The variations noted 

 in this species are so extraordinary that a revision of the known specimens appears 

 necessary. The oeciostome figured by Hincks has not been rediscovered ; the ovi- 

 celled specimens from the Mediterranean have never shown it. The arrangement 

 in quincunx of the tubes on the zoarial margins does not therefore appear as a 

 sufficient specific character if it is not supplemented by the character of the ovicell, 

 the oeciostome, and the cancelli. In adopting the name Lichenopora grignonensis 

 we are certain of having made a good identification, the comparison of the speci- 

 mens having been made directly. Some subsequent studies will make the synonyms 

 more specific. 



The composite zoaria appear to incrust algae, forming a greater or less thick- 

 ness with many lamellae superposed. Two specimens from Cocoa post office, 

 Choctaw County, Alabama, are hollow and measure 6 by 24 centimeters. 



Occurrence. Midwayan (Clayton limestone) ; Luverne, C'renshaw County, 

 Alabama (common) ; 1 mile west of Fort Gaines, Georgia (rare). 



Claibornian: Claiborne, Alabama (very rare). 



Jacksonian: Three and one-half miles southeast of Shell Bluff post office, 

 Georgia (common). 



Lower Jacksonian (Moodys marl) : Jackson, Mississippi (common). 



Middle Jacksonian: Wilmington, North Carolina (very common); near 

 Lenuds Ferry, South Carolina (very common) ; Eutaw Springs, South Carolina 

 (common) ; 18 miles west of Wrightsville, Johnson County, Georgia, (rare) ; Rich 

 Hill, 5J miles southeast of Knoxville. Crawford Count}'. Georgia ; 3J miles south of 

 Perry, Georgia (rare). 



