NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
135 
so vigorous that very frequently a zooecium, in every respect larger than the others, 
reproduces three undeformecl primoserial zooecia. We have observed no regeii- 
erated zooecia. 
This species differs from Membraniporidra laiicella in its larger micrometric 
dimensions and in the absence of a gymnocyst. 
Occurence. — Middle Jacksonian: Wilmington, North Carolina (common); 
Bich Hill, 51 miles southeast of Knoxville, Georgia (rare). 
Cotypes. — Cat. Nos. 63900, 63901, U.S.N.M. 
MEMBRANIPORIDRA LATICELLA, new species. 
Plate 26, figs. 3-5. 
Zoarium incrusting other bryozoa. The zooecia are distinct, ogival, broad , with 
a small convex gymnocyst ; the mural rim is salient, thin, curved, smooth, or slightly 
granular. The opesium is entire, oval, the narrow end at the front. The ovicell 
is large, globular, salient, smooth, distinct from the mural rim; it is deeply em- 
bedded in the distal zooecium. 
M easuremen ts . — Opesia 
ko= 0.40-0.50 mm. 
?o=0.20-0.30 mm. 
Zooecia 
[7,2=0.60-0.80 mm. 
^2=0.40-0.50 mm. 
Variations. — The mural rim is not always round. It sometimes has a small 
sharp termen dividing it into two parts. The gymnocyst is very irregular in form, 
but it is a constant feature. The regenerated zooecia with double mural rims are 
frequent. Figure 4 ( zri ) represents a special case where a regenerated zooecium re- 
places a normal zooecium but reversed in direction. Figure 5 ( zro ) illustrates an 
inverted ovicelled zooecium succeeding a normal zooecium. 
This species differs from Membraniporidra trigemma in its smaller zooecial 
dimensions and in the presence of a gymnocyst. 
Occurence. — Middle Jacksonian: Wilmington, North Carolina (very com- 
mon) ; Eutaw Springs, South Carolina (rare). 
Cotypes. — Cat. No. 63904, U.S.N.M. 
MEMBRANIPORIDRA PORRECTA Canu and Bassler, 1917. 
Plate 26, figs. 6-13. 
1917. Membraniporidra porrecta Canu and Basslek, Synopsis of American Early Tertiary 
Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 21, pi. 2, fig. 5. 
The zoarium is free, follicular, formed of two very thin leaves growing back to 
back and easily separable. The zooecia are large, elongate, distinct, oval, with a 
proximal, convex gymnocyst; the mural rim is very thin, salient, curved. The 
opesium is large, elliptical, entire. The ovicell is globular, little elevated, orna- 
mented with a frontal callosity ; it is deeply embedded. A distal septula and two 
lateral septulae and two distal impressions are present. 
M easurements. — Opesia 
ho =0.75 mm. 
h?=0.30 mm. 
Zooecia 
72=0.95 mm. 
72=0.38 mm. 
