NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 
Ill 
very irregular. The denticle placed on the pivot of the large avicularia is rather 
peculiar to this species, but it is not constant; it corresponds perhaps to a particular 
arrangement of the rachis. The known recent bryozoa never have this arrangement. 
The number and importance of the avicularia indicate calm waters. 
Occurrence. —Miocene (Choctawhatchee marl): Jackson Bluff, Ocklocknee River, 
25 miles southwest of Tallahassee, Florida (rare). Pliocene (Waccamaw marl): 
Waccamaw River, Horry County, South Carolina (very rare). 
Cotypes. —Cat. Nos. 68573, 68574, U.S.N.M. 
GEMELLIPORELLA VOKAX, new species. 
Plate 19, figs. 1-9. 
Description. —The zoarium incrusts shells, oysters, and bryozoa. The zooecia 
are little distinct, separated by a furrow, irregularly elliptical; the frontal is convex, 
surrounded by some large areolar pores which are scattered and covered over with 
a pleurocyst more or less granular. The apertura is deep, oval, the point below 
with rimule wide and notched; the peristomice is semilunar with a proximal mucro 
more or less developed. The ovicell is convex, little salient, deeply embedded 
in the distal zooecium; its orifice is very wide and can not be closed by the operculum. 
On each side of the apertura there is a round avicularium; very frequently the one 
between them becomes very long and fusiform. 
,, , » , \ha = 0.10 mm. „ . (Zz=0.40mm. 
Measurements .— Apertura , - _ 0 Zooecia . _ „. 
r l la = 0.08 mm. I Iz = 0.30 mm. 
Variations. —This species is exceedingly variable and takes the most fantastic 
aspects. The zooecia are only distinct on the small zoaria or on the margins of 
the large ones; at the center of the latter they are absolutely indistinct. The 
ancestrula is a small zooecium; it engenders two distal and four proximal zooecia. 
There are often interareolar costules. The reduction of its zooecial dimensions 
and the great development of the avicularia seems to indicate that this species 
required much oxygen. 
It is remarkable that the species has disappeared from the recent Gulf of 
Mexico after its existence in the same region throughout the Miocene and Pliocene. 
Occurrence. —Lower Miocene (Chipola marl): Chipola River, Calhoun County, 
Florida (rare). Miocene (Duplin marl): Wilmington and Natural Well, 2 miles 
southwest of Magnolia, Duplin County, North Carolina (common); Muldrows Mills, 
5 miles south of Maysville, South Carolina (rare). Miocene (Choctawhatchee 
marl): Jackson Bluff, Ocklocknee River, 25 miles southwest of Tallahassee, Florida 
(rare). Miocene (Yorktown formation): Yorktown, 3 miles southwest of Peters¬ 
burg, and other localities in Virginia (rare). Pliocene (Waccamaw marl): Wacca¬ 
maw River, Horry County, South Carolina (common). Pliocene (Caloosahatchee 
marl): Shell Creek, De Soto County (rare), and Monroe County, Florida (common). 
Cotypes. —Cat. Nos. 68575-68580, U.S.N.M. 
GEMELLIPORELLA PUNCTATA Canu and Bassler, 1919. 
Plate 5, figs. 7-9. 
1919. Gemelliporella punctata Canu and Bassler, Biology and Paleontology of the West Indies, 
Bryozoa. Publications of the Carnegie Institution of Washington, No. 291, p. 92, pi. 5, 
figs. 7-9. 
Description. —The zoarium is free, cylindrical, bifurcated. The zooecia are very 
little distinct, elongate, convex; the frontal is granular and surrounded with areolar 
