472 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
and in the disposition of the zooecia on the fronds. Possibly it should be considered 
as only a subgenus. 
PLAGIOSMITTIA REGULARIS Canu and Bassler, 1917. 
Plate 61, figs. 9-13. 
1917. Plagiosmittia regularis Canu and Bassler, Synopsis of American Early Tertiary 
Clieilostome Bryozoa, Bulletin 96, United States National Museum, p. 51, pi. 5, fig. 4. 
Description. — The zoarium is bilamellar; the fronds are flat, narrow bifurcated. 
The zooecia are much elongated, distinct, separated by a thread or a furrow and 
are much narrowed proximally. The frontal is flat or little convex and formed of 
a tremocyst with numerous crowded pores. The peristome is thin, salient; the 
apertura is semilunar with a very concave proximal border; the peristomice is 
irregular, but it often contains a false rimule limited by the avicularium. The 
ovicell is globular, little prominent; it is formed of a large circular area with 
small numerous pores, surrounded by a smooth collar, little salient; it is imbedded 
in the distal zooecia and opens into the peristomie. The avicularium is peristomial, 
placed more or less laterally; the mandible moves in the peristomie. 
Measurements. — Peristomice 
\hpe= 0.16 mm. 
U/?<?=0.10 mm. 
„ . fZs=0.75-1.00mm. 
Zooecia . OA 
[£3=0.20 mm. 
Apertura 
I /m— 0.06 mm. 
I /«.= 0.0G mm. 
Affinities. — This species is quite constant on the whole; many zooecia, how- 
ever, are marginated. 
It differs from Plagiosmittia porelloides in its larger dimensions (Lz= 0.75 
and not 0.60 mm) and in its avicularium always placed laterally in the peristomie. 
It differs from Plagiosmittia virgula in its larger micrometric dimensions 
(Lz= 0.75 and not 0.56 mm.) and in the absence of the large median avicularium. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (common). 
Upper Jacksonian (Ocala limestone) : Old Factory one-half mile above Bain- 
bridge, Georgia (rare) ; west bank Sepulga River, Escambia County, Alabama 
(common) ; Chipola River, east, of Marianna, Jackson County, Florida (common). 
Cotypes. — Cat. No. 62600, U.S.N.M. 
PLAGIOSMITTIA PORELLOIDES, new species. 
Plate 61, figs. 14-18. 
Description. — The zoarium is bilamellar; the fronds are flat, narrow, bifur- 
cated. The zooecia are much elongated, distinct, separated by a furrow or a salient 
thread, much narrowed inferiorly; the frontal is flat or a little convex and formed 
of a tremocyst with numerous and crowded pores. The peristome is thin, salient; 
the peristomice is oval ; the apertura is semilunar with a concave lower border. The 
ovicell is little salient, imbedded in the distal zooecium; it is formed of a large 
area with very fine pores, surrounded by a small, very thin collar; it opens into 
