NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
827 
Affinities. — This species exteriorly resembles worn specimens of Ascosoecia 
prominens ; it differs from it in the great thickness of the walls of the mesopores. 
It differs from Tretocycloecia reticulata in its branched, nonreticulate and 
smaller zoarium, in its much less numerous mesopores, and in its apertures, which 
are arranged in somewhat regular quincunx. 
Occurrence. — Midwavan (Clayton limestone) : Mabelvale, near Little Rock, 
Arkansas (rare). 
Cotypes. — Cat. No. 65256, U.S.N.M. 
TRETOCYCLOECIA GRANDIS, new species. 
Plate 150, figs. 7-10. 
Description. — The zoarium is flat, cylindrical, branched. The tubes are 
cylindrical or polygonal, bent obliquely at their extremity. The peristome is thin, 
orbicular, salient. The apertura is large. The mesopores are large, polygonal, 
irregularly grouped, and always closed by a calcareous pellicle rather resistant and 
finely perforated. The ovicell is orbicular. 
Diameter of the apertura 0.10 mm. 
Diameter of the peristome 0.15 mm. 
Measurements. Diameter of the branches 3.20 mm. 
Diameter of the mesopores 0.10 mm. 
Diameter of the ovicell 1.25 mm. 
Affinities. — This species offers much the aspect of the Pustulopora ( Clausa ) 
retifera Stoliczka, 1861. of the Latdorfian, the type of which we have not been 
able to compare. It differs in its mesopores, the diameter of which never surpasses 
that of the tubes, and in larger apertures (0.10 and not 0.06 mm.). 
The figured specimen is the only one found. The study of the species is 
therefore incomplete. 
Occurrence.— Lower Jacksonian (Mooclys marl) : Jackson, Mississippi (very 
rare). 
Holotype. — Cat. No. 65372, U.S.N.M. 
TRETOCYCLOECIA RETICULATA, new species. 
Plate 149, figs. 1-14. 
Description. — The zoarium is free, solid, cylindrical, large, reticulate. The 
tubes are very long, cylindrical, bent at a right angle at their extremity; the 
apertures are orbicular, grouped in irregular zones (in section). The mesopores 
are exteriorly small, polygonal, with thin walls, grouped in irregular, transversal 
zones, and of a large diameter in section; the walls are vesicular. Diaphragms 
in the tubes are rare. The ovicell is orbicular, hardly salient. 
(Diameter of the apertura 0.12 mm. 
M easurements. — Diameter of the mesopores 0.05 mm. 
| Diameter of the branches 5.00 mm. 
