64 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus HELIODOMA Calvet, 1907 



The zooecia are arranged following two spiral concentric series 

 which are alternately separated by a spiral series of vibracula. 



Genotype. — Heliodoma implicata Calvet, 1907. Recent (Tropical 

 Atlantic). 



Fig. 8. — Genus Heliodoma Calvet, 1907 



A-D. Heliodoma implicata Calvet, 1907. A. Free zoarium, natural size. B. 

 Entire colony showing the spiral arrangement of the zooecia and the setiform 

 vibracula. C. Aspect of the zooecia without ectocyst, X25. D. Inferior face 

 of the zoarium. (After Calvet, 1907.) 



Genus CELLARINIDRA Canu and Bassler, 1927 



1927. Cellarinidra Canu and Bassler, Classification Cheilostomatous Bryozoa, 

 Proc. U. S. Nat. Mus., vol. 69, Art. 14, p. 2. (Cellarina D'Orbigny, 1851, 

 preoccupied.) 



The zoarium is articulated; the segments are cylindrical with cells 

 on all the faces. The zooecia have a cryptocyst more or less developed 

 and angular; the opesium is elliptical. There are small interopesial 

 avicularia. 



Genotype. — Cellarinidra (Cellarina) clavata D'Orbigny, 1851. Cre- 

 taceous. 



Genus MEMBRANIPORA Blainville, 1830 



MEMBRANIPOKA ARCIFERA, new species 



Plate 2, fig. 6 



Description. — The zoarium encrusts shells. The zooecia are dis- 

 tinct, separated by a deep furrow, very large, elliptical or irregular; 

 the mural rim is thick, regular, finely granular with a salient and 



