98 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
necessary therefore to await more abundant material before the generic position can 
be determined. 
Occurrence .— Middle Jacksonian (Castle Hayne limestone) : Wilmington, 
North Carolina (very rare). 
Holotype.— Cat. No. 63871, U. S N. M. 
MEMBRANIPORINA BENJAMINI Canu and Bassler, 1917. 
Plate 21, fig. 1. 
1917. Membraniporinu benjamini Canu ami Basslf.e, Synopsis of American Early Tertiary 
Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 11, pi. 1 , fig. l. 
Description . — The zoarium is incrusting. The zooecia are large, elongate, 
elliptical, and distinct; the mural rim is rounded, smooth, everywhere of equal 
width. The opesium is median, elliptical, entire. In the vicinity of the septulae 
there is often an incomplete small canal. 
Measurements . — 
. \ho=0.57 mm. 
°pesiaj^_o go mm . 
Zooecia 
jZs=0.65-0.70 mm. 
\lz= 0.40-0.45 mm. 
Affinities . — Only the fragment figured, which is of considerable interest, has 
been found. In the proximal part of the zooecium in front of each septula there is 
a sort of incompletely calcified tubule, serving probably to protect the mesenchyma- 
tous filaments which pass from one zooecium to another. 
This interesting species is named after Dr. Marcus Benjamin, the efficient editor 
of the United States National Museum, to whom we are indebted for many 
courtesies. 
Occurrence . — Middle Jacksonian : Rich Hill, of- miles southeast of Knoxville, 
Crawford County, Georgia (very rare). 
Holotype. — Cat. No. 62567, U.S.N.M. 
MEMBRANIPORINA TUBULOSA, new species. 
Plate 80, figs. 2-7. 
Description . — The zoarium is unilaminar, tubular , and incrusts very small algae. 
The zooecia are distinct, elongated, hexagonal; the mural rim is level, but little 
elevated, much enlarged at the base to form a concave cryptocyst. The opesium 
is anterior, elliptical, entire ; the lateral walls bear two small septulae. 
M easurements.— 
. | ho =0.20-0.22 mm. 
°P esla lfo=0.17 mm . 
Zooecia 
Zs=0.40-0.45 mm. 
Zs=0.30-0.32 mm. 
Affinities . — The bifurcation of the zoarium corresponds to that of the alga 
which served as a substratum. At this bifurcation there is often a giant zooecium. 
The calcified zooecia have a concave cryptocyst perforated by a large round pore. 
It appears to us that endozooecial ovicells may be present, but as we are not able 
to confirm the observation by a dissection it is necessary to await better specimens 
before placing the species finally. 
