NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
357 
SCHIZOMA VELLA ELONGATA, new species. 
Plate 46, fig. 17. 
Description. — The zoarium is free, formed of two lamellae, back to back and 
inseparable; the zooeeia are distinct, very elongated , fusiform, separated by an 
improminent thread; the frontal is flat and ornamented with small, wide open 
tremopores. The aperture is suborbicular ; the rimule is very wide, concave, scarcely 
distinct from the anter. The ovicell is globular and salient, ornamented with a 
tremocyst analogous to that of the frontal. The median avicularium is small, 
triangular, without salient beak and imbedded in a cavity. 
Measurements. — Aperture 
ha~ 0.10 mm. 
hz=0.10 mm. 
Zooecium 
[ Lz=1.10 mm. 
I lz^ 0.30 mm. 
Affinities. — This species is characterized by its very great zooecial length. We 
have observed two calcified zooeeia ; the aperture is covered by the tremocyst and 
replaced by a small pore. The physiologic role of such zooeeia is unknown to us. 
Occurrence. — Middle Jacksonian : Three and one-half miles north of Grovania, 
Georgia (rare). 
Holotype. — Cat, No. 64060, U.S.N.M. 
SCHIZOMAVELLA ARBOREA, new species. 
Plate S6, figs. 1-6. 
Description. — The zoarium is free, arborescent , rectangular, or cylindrical. 
The zooeeia are disposed in four longitudinal rows, alternating and placed back 
to back; they are hexagonal, very little elongated, separated by a prominent thread. 
The frontal is a direct tremocyst with large pores. The aperture is small, oblique 
and formed of a semilunar anter and of a very wide rimule of little depth. The 
ovicell is large, globular, salient, punctate; it is closed by the zooecial operculum 
which is larger on the ovicelled zooeeia. The median avicularium is elliptical, 
salient, separated into two parts by a wide pivot. 
M easurements. — Aperture 
[Aa,= 0.10mm. 
\Z<z=0.10 mm. 
Zooeeia 
As=0.80 mm. 
lz— 0.72 mm. 
Variations. — The median avicularium is very variable on the same fragment; 
it is quite small (Z=0.08 mm.) or very long (Z=0.25 mm.), but it always remains 
elliptical (figs. 2, 5). 
The zoarium is square (figs. 2, 6) or quite rounded (figs. 4, 5). 
The ovicell does not entirely surround the aperture and is quite different from 
the ovicell of other species of the same genus. 
Affinities. — This species is well characterized by the arborescent form of its 
zoarium. In its direct tremocyst and in the form of its aperture, it differs from 
species of the same genus. 
It differs from Cellaria schreibersi Eeuss, 1869, in which the zoarium is vin- 
cularian in its median avicularium and its bifurcated zoarium. • 
