62 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Harmer, 1923, proved that this genus should be called Eucratea 

 Lamouroux, 1816. We maintain it for the reason of least change 

 and its use for half a century. 



Genus BRETTIA Dyster, 1858 



The zoarium with single 

 rowed zooecia, the proximal 

 portion of which is subtubu- 

 lar. The radicle starts from 

 the dorsal surface at the dor- 

 sal end. 



Genotype. — Brettia pellucida 

 Dyster, 1858. Recent. 



Genus CORYNOPORELLA 

 Hincks, 1888 



As in Brettia, but there is 

 an articulated avicularium at- 

 tached to the side of the 

 opesium. 



Genotype . — Corynoporella 

 tenuis Hincks, 1888. Recent. 



A superfluous genus accord- 

 ing to Waters, 1900. 



Family BIFLUSTRIDAE 

 Smitt, 1872 



Membraniporae without 

 ovicells. The zooecia are rec- 

 tangular (seen on their dorsal 

 face). No spines. 



In this family we classify all 

 the genera of the first group 

 of Membraniporae as we di- 

 vided them in 1920 (p. 85), ex- 

 cept Discoflustrellaria D'Or- 

 bigny, 1850, which we now refer 

 to the family Mamilloporidae. 

 History. — Biflustra is a zoarial genus established by D'Orbigny, 

 1852, and classed in his family of Flustrellaridae. It embraced all 

 of the bilamellar Membranipores. Three recent species were classed 

 here: The first and the third are of the Savartii group (Waters, 1905) 

 and the second is one of the Costulae. 



Busk, 1859, classed Biflustra in the Escharidae: He introduced here 

 Biflustra delicatula which we know to be a synonym of Flustra savartii 

 Savigny-Audouin, 1926. Smitt, 1872, formed the family of Biflus- 



Fig. 6.— Genus Brettia Dyster, 1858 



A. Brettia pellucida Dyster, 1858 (afte r 

 Hincks, 1880). A. Zooecia. According to 

 Levinsen, 1909, this genus is purely zoarial 

 and its genotype is a Gemellaria. 



B-D. Brettia minima Waters, 1900. B. 

 Colony, natural size. C. Frontal view of 

 zooecia, X12. D. Dorsal surface X25. 

 The radicles start from the dorsal surface 

 at the distal end. (After Waters, 1900.) 



