310 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



tical, and are followed by large (fig. 10) or smaller (figs. 11, 13) lacunae, which 

 vary in number, although there are always at least two. 



The tangential sections show very clearly the existence of a lumen and of large 

 lumen pores (fig. 12). 



Affinities. This species differs from the recent Acanthocclla tu'bulifera Hincks, 

 1881, in its larger number of lumen pores (3 or 4 instead of 2). 



It differs from Cribrilina suggerens Waters, 1881, in its zoarium. which is not 

 bilamellar and in its larger micrometric dimensions (la 0.12 mm. and not 

 0.06mm.). 



Occurrence. Middle Jacksonian (Castle Hayne limestone) : Wilmington, North 

 Carolina (rare). 



Cotypes. Cat. No. 62587, U.S.N.M. 



Genus CRIBRENDOECIUM Canu and Bassler, 1917. 



1917. Cribrendoccium CANU and BASSLEB, Synopsis of American Early Tertiary Cheilo- 

 stome Bryozoa, Bulletin 96, United States National Museum, p. 36. 



The ovicell is endozooecial. The costules are separated by a small initial slit 

 and some medium-sized lacunae; they have no lumen pores. The aperture is formed 

 of a semilunar anterior portion and a larger and concave posterior part separated 

 by two cardelles. The aperture of the ovicelled zooecia is larger. Large iriter- 

 zooecial avicularia are present. 



Genotype. Cribrendoecium tenuicostulatum, Canu and Bassler, 1917. 



This genus shows the closest resemblance to Hippopodina Levinsen, 1909, in the 

 nature of its ovicell and its oral dimorphism. On the other hand, its interzooecial 

 avicularia and the structure of its ovicell marked with two lateral cicatrices, relate 

 it to Figularia Jullien, 1880. It is therefore very probable that the species of Cri- 

 brendoecium are provided with a compensatrix, just as in the two genera cited and 

 as the nature of its aperture would predict. 



CRIBRENDOECIUM TENUICOSTULATUM Canu and Bassler, 1917. 



Plate 43, fig. 8. 



1917. Cribrendoecium tenuicostulatum CANU and BASSLER, Synopsis of American Early 

 Tertiary Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 36, 

 pi. 4, fig. 1. 



Description. The zoarium incrusts shells. The zooecia are distinct, elongated, 

 separated by a furrow, elliptical, fusiform; the frontal is convex; the costules are 

 very thin, numerous, without lumen pores, and separated by very small lacunae. 

 The apertures of the ordinary zooecia are formed of a semilunar anterior and a 

 very large, straight posterior part separated by two small cardelles; the aperture 

 of the ovicelled zooecia is larger and its posterior portion is convex. The ovicell 

 is endozooecial and exteriorly is prominent and transverse; it is formed of two 

 calcareous deposits; the outer one is incomplete and leaves two lateral cicatrices 

 in the form of a cross. The avicularia are interzooecial and are elongated, spatu- 

 late, perforated by a long slit and generally without pivot. 



