124 



BULLETIN 106, UNITED STATES NATIONAL, MUSK I M. 



although very natural in themselves, appear to belong to different families which 

 the zoologists alone can determine. 



Genus PERIPOROSELLA Canu and Bassler. 1917. 



1917. Periporosella CANT and BASSLEK, Synopsis f American Eany Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. IS. 



Each zooecium is surrounded by a special series of dietellae (12 to 16) com- 

 municating with two large septulae. 



*<* 



it'!*' 



A. Penporosella 



B. Ellisina 



D. Membrani 



E. Tremopora I""- Larnacius 



FIG. 30. Membraniporao with hyperstoinial ovicells. always closed by the opercular valve. 



A. Pcriporosclla tnnfilln Canu and Bassler. 1917. X 20. Middle Jacksonian, Wilmington, 

 North Carolina. 



B. Ellisina lircris, new species, X 20, Middle .Tai-ksoiiHin. near Lemuls Ferry, South Carolina. 



C. Grammella i>iisilln, new species, X -(>. Virksbnrsian, 1 mile north of Monroeville, 

 Alabama. 



D. Man lira n liioridra trii/ciiiin/i, new species. X 20. Middle Jacksonian. Wilmington, North 

 Carolina. 



E. TrcmoiiOi'd ilcixlmcnnthn Ortmann. 1890. Recent. 



F. Laniuciiis curnigrr Busk, 1S.~>2. Recent. 



Genotype. Pcriporosclla 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 Pcriporosclla. they 

 are, on the contrary, arranged all about the zooecium as in the family Adeonidae. 

 These dietellae arc invisible externally, and they In-come apparent only in tangential 

 sections of some depth. 



