NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
115 
DIVISION n. WITH INTERZOOECIAL AVICULARIA DIFFERENTIATED. 
The species of this section are as beautiful as they are well characterized. Theii 
avicularia when present are similar in every respect to those of the recent species, 
such as Hincksina pyrula , II . flustroides , II. sceletos , etc., of which we have figured 
the mandibles. They are, however, without a pivot. One must not confound the 
species of this genus with those of the genus Omatella Canu, 1900, in which the 
ovicells are hyperstomial. 
HINCKSINA ELEGANS, new species. 
Plate SO, figs. 12-15. 
Description. — The zoarium is unilamellate, creeping over algae. The zooecia 
are elongate, distinct, elliptical, provided with a gymnocyst ; the mural rim is 
thicker in the proximal part below, finely granulated, adorned on its summit with a 
crown of large granules or of hollow spines; the two distal spines are larger, con- 
stant, and symmetrical. The opesium is elliptical and entire. The ovicell is a 
small distal convexity, smooth and indistinct; the border of the opesium is thick in 
the ovicelled zooecia. 
M easurements. — Opesia 
ho= 0.32-0.37 mm. 
Ze>=0.18-0.20 mm. 
Zooecia 
| £,3= 0.45-0.47 mm. 
\lz= 0.32-0.35 mm. 
Affinities. — Of this elegant species we possess unfortunately only the three 
figured specimens. The adornment of its mural rim is a small masterpiece of sculp- 
turing which could well serve as model for the decorator. The little granules must 
be the traces of small hollow spines attenuated in the process of fossilization. The 
zooecia with ovicells have also the aspect of regenerated zooecia. It may be, there- 
fore, that the female polypide succeeds the male in total regeneration. 
This species differs from Hincksina costulifera in the presence of its two distal 
spines, which are larger than the areal spines, and in the opesial thickening of the 
ovicelled zooecia. 
Occurrence. — Vicksburgian (“Chimney rock” of Marianna limestone) : 1 mile 
north of Monroeville, Alabama (very rare). 
Gotypes. — Cat. No. 64232, U.S.N.M. 
HINCKSINA PARVAVICULARIA, new species. 
Plate 22, figs. 14, 15. 
Description. — The zoarium is incrusting shells. The zooecia are large, elon- 
gated, distinct, pyriform or elliptical, with or without gymnocyst; the mural rim is 
prominent, convex, ornamented with sixteen large hollow spines. The opesium is 
elliptical, entire. The interzooecial avicularium is relatively small and unsvm- 
metrical. 
ir . • A<?=0.40-0.4o mm. 
Measurements. — Upesia 7 „ „„ „ 
L \lo= 0.25-0.30 mm. 
-0.45 mm. 
Zooecia 
Lz— 0.60-0.70 mm. 
lfe=0.40-0.45 mm. 
Affinities. — This species differs from Hincksina flustroides Hincks, 1880, in its 
larger spines, its thicker mural rim, and its less symmetrical avicularia. The 
