124 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
although very natural in themselves, appear to belong to different families which 
the zoologists alone can determine. 
Genus PERIPOROSELLA Camu and Bassler. 1917. 
1917. Periporosella Canu and Bassler, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United Stated National Museum, p. 18. 
Each zooecium is surrounded bv a special series of dietellae (12 to 16) com- 
municating with two large septulae. 
A. Periporosella 
B. Ellisina 
C. Grammella 
D. Membraniooridra 
E. Tremopor?. E Larnacius 
Fig. 30. — Membraniporae with hyperstomial ovicells, always closed by the opercular valve. 
A. Periporosella tantilla Canu and Bassler, 1917, X 20, Middle Jacksonian, Wilmington, 
North Carolina. 
B. Ellisina brevis, new species, X 20, Middle Jacksonian, near Lenuds Ferry, South Carolina. 
C. Grammella pusilla, new species, X 20, 
Alabama. 
D. Membraniporidra trigemma, new species, 
Carolina. 
E. Tremopora dendracantha Ortmann, 1890. 
F. Larnacius corniger Busk, 1852. Recent. 
Vieksburgian, 1 mile north of Monroeville, 
X 20. Middle Jacksonian, Wilmington, North 
Recent. 
Genotype. — Periporosella tantilla Canu and Bassler, 1917. Jacksonian. 
In all the other genera of Membranipores provided with dietellae the latter 
occupy only the anterior half of the zooecium. In the genus Periporosella they 
are, on the contrary, arranged all about the zooecium as in the family Adeonidae. 
These dietellae are invisible externally, and they become apparent only in tangential 
sections of some depth. 
