NORTH AMERICAN EARLY TERTIARY BRYOZOA. 343 



Variations. The oral sinus disappears frequently on account of the consid- 

 erable thickening of the frontal (fig. 2), but it persists at the base of the peristomie 

 and is always visible in the interior (fig. 8). 



Eschara incumbens Lonsdale, 1845, is merely this same species provided with 

 its ovicells. They, are very large ; their frontal is thickened considerably on the 

 parietal olocyst a very rare phenomenon in the Cheilostomes, where the ovicell 

 is almost always of the same nature as the frontal. By dissecting the ovicell the 

 apertura is always visible and very constant in form and size. The oral avicularium. 

 is not at all constant; it disappears over entire fronds when they have the aspect 

 of Eschara texta Gabb and Horn, 1862. Another character common to the two 

 species is " The alternate elevations and depressions of the cellular surface of this 

 remarkable species give it, to the naked eye, very much the appearance of a woven 

 fabric," quite visible in our figure 3, and noted in 1862 by Gabb and Horn. 



According to the tangential section (fig. 6) the tremocyst does not appear to 

 repose on a calcified olocyst. 



Affinities. This species differs from SchisopodreUa linca Lonsdale, 1845, in 

 its less zooecial width (Zs=0.3Q-0.45 mm. instead of 0.45 mm.-0.65 mm.), and 

 in a single avicularium placed below the apertura and not above it. 



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

 common). 



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

 Springs, South Carolina (common, type locality) ; Baldock, Barnwell County, 

 South Carolina (common) ; near Lenuds Ferry, South Carolina (common) ; 3| miles 

 north of Grovania, Georgia (rare) ; 3 miles south of Perry, Georgia (common) ; 

 17 miles northeast of Hawkinsville, Georgia (rare) ; one-half mile southeast of 

 Georgia Kaolin Co. Mine, Twiggs County, Georgia (rare). 



Jacksonian (Zeuglodon zone) : Cocoa Post Office, Choctaw County, Alabama 

 (rare). 



Plesiotypes.Czt. No. 64051. U.S.N.M. 



Genus STEPHANOSELLA Canu and Bassler, 1917. 



1917. Stephanosella CANTJ and BASSLER, Synopsis of American Early Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. 40. 



The ovicell is hyperstomial and embedded in the distal zooecia. It opens 

 above the aperture by an especial orifice. The frontal is a smooth olocyst. No 

 spines. The ovicelled zooecia have a large aperture and their avicularium is frontal. 



Genotype. Schizoporella (Lepralia) Maperta Michelin, 1845. 



Range. Jacksonian-Eecent. 



Our genus does not exactly correspond to the Schizoporella biaperta group 

 of Waters, 1913. We prefer to take into consideration the nature of the frontal 

 rather than the muscular attachments, which are impossible to verify on the fossils. 

 If the areolae were more frequently observed in the species of this genus, it would 

 be preferable to unite them with the genus Lacerna Jullien. 1888. 



Stephanosella, differs from Lacerna in its oral avicularia and in the absence 

 of spines. 



