NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
113 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (rare) ; Eutaw 
Springs, South Carolina (rare) ; Rich Hill, Crawford County, Georgia (common) ; 
18 miles west of Wrightsville, Jackson County, Georgia (very rare). 
Upper Jacksonian (Ocala limestone) : 1-1 miles above Bainbridge, Georgia. 
Cotypes.— Cat. No. 63878, U.S.N.M. 
HINCKSINA SMITHI, new species. 
Plate 21, figs. 15-17. 
Description. — The zoarium incrusts pebbles. The zooecia are elliptical, dis- 
tinct, and may or may not have a gymnocyst ; the mural rim is thin, salient, convex, 
ornamented with 8 to 10 spines. The opesium is elliptical and very slightly 
crenulated. The endozooecial ovicell is a quite visible convexity. 
Measurements. — Opesia 
|Ao=0.30 mm. 
|Zu=0.14- 0.17 mm. 
Zooecia 
Lz— 0.40-0.45 mm. 
73=0.22-0.25 mm. 
A-ffinities. — The mural rim is sometimes enlarged a little at the base as in 
Hincksina ocalensis , but the dimensions are much smaller and the spines more nu- 
merous. These same small dimensions and its very slightly crenulated opesium will 
distinguish it from Hincksina reptans. 
Hincksina smithi differs from the recent H. maderensis Waters, 1898, in the 
absence of the five peculiar distal spines and in its small ovicell. 
We dedicate this elegant species to Dr. Eugene A. Smith, State geologist of 
Alabama, who has been ever ready to further our researches with material from 
his State. 
Occurrence. — Middle Jacksonian: Eutaw Springs, South Carolina (very rare). 
Holotype. — Cat. No. 63877, U.S.N.M. 
HINCKSINA JACKSONICA Canu and Bassler, 1917. 
Plate 22, figs. 4-9. 
1917. Hincksina jacksonica, Canu and Bassler, Synopsis of American Early Tertiary 
Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 15, pi. 1, fig. 6. 
Description. — The zoarium is free, bi lamellar, easilv divisible into two layers. 
The zooecia are elongated, distinct, elliptical, often with a small gymnocyst; the 
mural rim is convex, enlarged at the base, finely granulated. The opesium is 
terminal, elliptical, regular, very finely denticulated. The ovicell is endozooecial 
and little apparent; it appears as a small distal convexity. Avicularian zooecia 
are very rare. 
M easurements.—' Opesia 
f ho =0.35-0.45 mm. 
I Zo= 0.20-0.25 mm. 
Zooecia 
| Lz 
\lz~ 
=0.45-0.65 mm. 
=0.35-0.40 mm. 
The two lamellae forming the zoarium separate very easily, each preserving 
its own base. 
Variations. — The zooecial length is quite variable; both long and short zooecia 
may occur (fig. 6). The avicularian zooecia or interzooecial avicularia are rather 
55899— 19— Bull. 106 8 
