NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
529 
apertura is somewhat elongated, suborbicular, and formed of a large semilunar 
anter and of a very convex, somewhat smaller poster; the two cardelles are pro- 
longed in the interior as far as the lateral zooecial walls. The ovicell is endozooe- 
cial, small, little salient, transverse, of the same nature as the frontal. The two 
oral avicularia are orbicular, without pivot, very salient. 
Measurements . — Apertura 
|Aa=0.16-0.18 mm. 
{la=0. 16-0.18 mm. 
Zooecia 
rZs=1.00mm. 
}Z3=0.60 mm. 
Variations . — Evidently the oral avicularia are not always equally salient, but 
their presence is very constant. 
The cardelles are very characteristic. They are prolonged as a prominence in 
the interior of the zooecia as far as lateral walls and thus form two powerful 
condyles. 
That which we take for dietellae are perhaps only the cavities of the avicularia 
(fig. 11) . We do not believe this for the following reasons : 
1. In (J heilopora prelueidioides these cavities are visible on the specimens 
which have no exterior avicularium apparent. 
2. In Cheilopora saillans , if we illuminate strongly from below the prepara- 
tion showing the zooecial interior, we note that the apertura becomes naturally 
brilliant, but that the cavities remain dark, and that they have therefore no orifice 
in common with the avicularia. 
Nevertheless a relationship between these dietellae and the avicularia is 
always possible. The width of the apertura of the ovicelled zooecia is 0.30 mm. 
Affinities . — It is rather difficult to separate this species from Cheilopora 
transversa and 0 heilopora transversoides in which the exterior aspect is similar, 
but it differs from them in its more salient avicularia and in its apertura never 
transverse, but always round or pyriform. 
Occurrence . — Middle Jacksonian: Wilmington, North Carolina (common); 
3| miles south of Perry, Georgia (rare) ; 17 miles northeast of Hawkins ville, 
Georgia (rare) ; one-half mile southeast of Lily, Georgia (rare). 
Cotypes. — C'at. No. 61176, U.S.N.M. 
CHEILOPORA TRANSVERSA, new species. 
Plate 69, figs. 6. 
Description . — The zoarium is free, bilamellar, formed of two lamellae, back 
to back. The zooecia are distinct, lozenge-shaped, entirely surrounded by a sepa- 
rating, salient thread ; the frontal is somewhat convex and perforated by numerous 
small tremopores, disposed in quincunx. The apertura is transverse , subelliptic, and 
provided with two large cardelles; the anter is less convex than the poster, but 
it is wider. The peristome is complete and somewhat salient. The ovicell is 
endozooecial, little salient, convex, transverse, of the same nature as the frontal. 
The two oral avicularia are a little salient, orbicular, without pivot. 
. fZa=0.12-0.16mm, 
ill easurements . — Apertura ■ , „ r ,„ 
1 [Z«.= 0.20mm. 
55899— 19— Bull. 106 34 
„ . rZA=1.00mm. 
ZOOeCia 7 a Ur\ a a a 
|fo=0.70-0.90 mm. 
