14 BULLETIN 16 5, UNITED STATES NATIONAL MUSEUM 



and of the same form as the zooecium; the inner opesium is small, 

 elliptical, elongated, visible above the cryptocyst; the latter is sur- 

 mounted by a broad distal shelf, perforated by two large septulae. 

 The avicularia are interzooecial, lozenge-shaped with a sharply 

 pointed beak; they are also arranged in longitudinal rows. 

 Measurements. — 



T . (A<? = 0.12-0.15 mm. „ . fZs=0.5 mm. 



Inner opesium { no Zooecia \ 1 „ _ 



[70 = 0.08 mm. [72=0.3 mm. 



Structure. — The structure with double opesia characterizes the 

 family of the Synaptaeellidae Maplestone, 1911, but it is also visible 

 in some species of the Scrupocellariidae Levinsen, 1909. It can be 

 observed in the following species : 



Heterocella (?) pentagona Canu and Bassler, 1929, from the 

 Philippines, which has no avicularia. Vincularia grama Brydone, 

 1930, from the English Senonian has two to four septulae on the 

 distal broad shelf, no avicularia, and an endozooecial ovicell. 



Membranipora cingulata Levinsen, 1925, of the European Danian 

 has an identical zooecial structure, but here the ovicell is also 

 unknown. 



Scrupo cell aria ferox Busk, 1852, as figured by Canu and Bassler, 

 1929, is a recent species presenting all the characters of the genus 

 Scrupocellaria. 



Actually, then, there is no genus for the reception of this small 

 species. The rarity of specimens prevents us from making the sec- 

 tions necessary to determine its structure. 



A similar broad distal shelf, but not perforated by the septulae, 

 is observable in Eschar a erina D'Orbigny, 1852, from the French 

 Senonian and in the recent species Caberea brevigaleata Canu and 

 Bassler, 1929, from the Philippines, Cauda arachnoides Lamouroux, 

 1816, and Scrupocellaria scrupea Busk, 1848. 



Very probably the genus Synaptacella Maplestone, 1911, would 

 therefore be more correctly placed in the Scrupocellariidae. The 

 fossil species cited, Vincularia grama, Vincularia acutirostris, and 

 Eschara erina would be the Cretaceous ancestors of this family. 



Occurrence. — Vincentown limesand: Vincentown, N.J. (very rare). 



Holotype.—U.S.'NM. No. 73858. 



Family HINCKSINIDAE Canu and Bassler, 1927 



Genus APLOUSINA Canu and Bassler, 1927 



APLOUSINA CONTUMAX, new species 



Plate 1, Figukes 4-7 



Description. — The zoarium encrusts fragments of shells and of 

 Coscinopleura. The dorsal is a very thin pellicle covering only the 

 smallest perforations of the substratum. The zooecia are large, ir- 



