NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
673 
Forma DIASTOPORA Lamouroux, 1821. 
1821. Diastopora Lamotjkoux, Exposition Methodique des Polypiers, p. 42. 
The zoarium is unilaminar. 
Historical. — Gregory, 1899 (p. 127), included in the genus Diastopora, all the 
free forms, uni- or bi-laminar, branched or bushy. Even thus understood, this is 
not a natural genus, because the ovicell is of a quite varied form and nature. 
Under these conditions we believe it necessary to recognize the zoarial forms in the 
exact sense of their authors. The discovery of their ovicells will later permit the 
classification of the species. According to D'Orbigny, Diastopora is unilamellar, 
Bidiastopora is bilamellar and branched, and Mesenteripora is lobate. bushy, and 
meandriform. 
DIASTOPORA TUBAEDES, new species. 
Plate 106, figs. 4, 5. 
Description. — The zoarium incrusts small branched algae; it is cylindrical, tubu- 
lar, branched; the zone of growth is very small. The tubes are cylindrical, ar- 
ranged in regular quincunx, straight, and never bent upward. The peristome is 
thin, orbicular, oblique; the peristomie is salient, rectilinear. 
Measurements . — < 
Diameter of the peristome 
Distance between the peristomes 
Separation of the peristomes 
Length of the peristomie 
Occurrence. — Midwayan (Clayton limestone) : Luverne, 
Alabama (very rare). 
TIolotype. — Cat. No. 65421, U.S.N.M. 
0.14 mm. 
0.40-0.50 mm. 
0.52 mm. 
0.16 mm. 
Crenshaw County, 
DIASTOPORA TUBIFORMIS, new species. 
Plate 121, fig. S. 
Description. — The zoarium incrusts the delicate branched radicells of algae; 
it is hollow , cylindrical, branched; the zone of growth is rather wide. The tubes 
are distinct, cylindrical, somewhat bent upward, striated transversal] y. The peris- 
tome is elliptical, thin, a little salient, often closed by an entire smooth lamella. 
There is no peristomie. 
Measurements . — 
Diameter of the peristomes 0.12 (0.12-0.16) mm. 
Distance between the peristomes 0.4^U0.60 mm. 
Separation of the peristomes 0.50 mm. 
Occurrence. — Middle Jacksonian: Near Lenuds Ferry, South Carolina (rare). 
Holotype. — Cat. No. 65299, U.S.N.M. 
55899— 20— Bull. 106- 43 
