NORTH AMERICAN EARLY TERTIARY BRYOZOA. 529 



aportura is somewhat elongated, suborbicular. and formed of a large seinilunar 

 anter and of a very convex, somewhat smaller poster; the two carclelles 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. 



,, (Atf =0.16-0.18 mm. . rZ2=1.00mm. 



Measurements. Apertura Zooecia , 



[ta=0.16-0.1S mm. (fe=O.GO mm. 



Variations. Evidently the oral avicularia arc 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 ;md 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 Cheilopora preliicidioides these cavities are visible on the specimens 

 which have no exterior avicularium apparent. 



2. In Cheilopora saiUans. 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 Cheilopora 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) ; 

 3J miles south of Perry, Georgia (rare) ; 17 miles northeast of Hawkinsville, 

 Georgia (rare) ; one-half mile southeast of Lily, Georgia (rare). 



Cotypes.f.'Ai. No. 641T6, U.S.N.M. 



CHEILOPORA TRANSVERSA. new species. 



Plate 69, figs. G. 



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 ovicel! is 

 endozooecial, little salient, convex, transverse, of the same nature as the frontal. 

 The two oral avicularia are a little salient, orbicular, without pivot. 



/w=0.12-0.16mm. . r. = 



Zft=0 . 20 mm> !Cla jfe=0.70-0.90 mm. 



55899 19 Bull. 106 - 34 



