NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
627 
The ovicell is hyperstomial, placed on the distal zooecium; it is never closed 
by the operculum; its orifice is large; it is formed of two calcareous layers, of- which 
the external one is frequently incomplete and circumscribes a more or less large 
frontal area. 
Variation *. — In the interior of certain apertures there is a calcareous arched 
lamella or indeed a tooth when this lamella is incomplete. 
In the interior (fig. 2) the ancestrula is an ordinary zooecium; viewed from 
the inner face it has the aspect of a circle perforated by three pores (fig. 5) sur- 
rounded by a calcareous ring arid by six hexagons perforated by three, four or five 
pores. On the exterior it. is surrounded by radicular zooeciules, as is the habit of 
all the species attached to submarine bodies (fig's. 7, 8). 
The zooecia are regularly cylindrical; the internal surface is smaller than the 
external surface; the discrepancy is filled by the zooeciules, which we call com- 
pensation zooeciules; they are more or less numerous (fig. 3). 
On their inner face, near the ancestrula, there are some large avicularia with 
bar; their mandible was semielliptical and transverse (figs. 4, 5). 
On the external face (fig. 0) there are large membraniporoid zooecia superposed 
on the others and always situated near the center. Their function is unknown. 
The base of the zooecia is perforated; these pores are the extremities of the 
long tubules which open also on the external face. These tubules must be intended 
to give lightness to the zoariiun. 
Occurrence . — Claibornian (Gosport sand) : Claiborne, Alabama (very com- 
mon) ; Gopher Hill, Tombigbee River, Alabama (common) ; one mile southwest 
of Rockville, Clarke County. Alabama. 
Claibornian (Lisbon formation) : Wautubbee Hills, four miles south of Enter- 
prise. Clarke County, Mississippi (common). 
Claibornian (Cook Mountain formation) : Moseleys Ferry, Caldwell County, 
Texas (very rare). 
Lower Jacksonian: Three and one-half miles southeast of Shell Bluff post office, 
Georgia (rare). 
Lower Jacksonian: Jackson, Mississippi (very common). 
Plesiotypes. — 'Cat.. No. 62809, U.S.N.M. 
SCHIZORTHOSECOS GRANDIPOROSUM, new species. 
Plate IS, figs. 10-15. 
Description . — The zoarium is cupuliform and little concave. The zooecia are 
distinct exteriorly, tubular, terminated by a contracted peristomie. The apertura 
is placed at. the base of the peristomie; it bears a rounded rimule; the peristomice 
is oval. The peristomes are separated by some compensation zooeciules with irregu- 
lar orifices. On their inner face the. zooecia are indistinct; they each contain one 
large and one small poi’e. At the. base of each zooecium there are a dozen very 
small pores. 
