404 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Exochella Jullien, 1888. 
Didymosella Canu and Bassler, 1917. 
Trypematella , new genus. 
They are differentiated from one another in their functions of calcification and 
their avicularia. 
A. Bathosella 
B. Romancheina 
C. Peristomella 
Exochella 
E. Didymosella F. Trypematella 
Fig. 119. — Genera of the subfamily Peristomellae Ganu and Bassler, 1917. 
A. Bathosella aspera Ulrich, 1901, X20. Lowest Eocene of Maryland. 
B. Romancheina martiali Jullien, 1888, X 20. Recent.. 
C. Peristomella coccinea Abildgaard, 1805. Recent. 
D. Exochella longirostris Jullien, 1888, X 31. Recent. 
E. Didymosella crassa Canu and Bassler, 1917, X 20. Vicksburgian of Alabama. 
F. Trypematella papulifera, new species, X 20. Pleistocene of California. 
Genus BATHOSELLA Canu and Bassler, 1917. 
1917. Bathosella Canu and Bassleb, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 43. 
The aperture is oblique without lyrula, cardelles, or rimule. The ovicell is 
embedded in the distal zooecia. It opens above the aperture and below the frontal 
mucro in the locella. The frontal is a thick olocyst more or less covered by a 
pleurocyst. The zooecia are indistinct. The avicularia are simple and irregularly 
placed. The areolae are very rare. No spines. 
Genotype. — Bathosella ( Mucronella ) aspera Ulrich, 1901. 
Range.-^- Upper Cretaceous-Midwayan. 
