582 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
It differs from Perigastrella depressa , of which it has the zooecial form and 
general appearance, in the presence of its -spines, in its frontal granulations, and in 
its labial mucro. 
The difference between it and Hemicyclopora parajuncta is quite small; it 
differs from it, however, in its visible areolae, its much larger labial mucro, and 
in its frontal granulations. 
It differs from Perigastrella ovoidea in its smaller dimensions (Lz— 0.50 and 
not 0.75 mm.) and in its transversal and trapezoidal apertura. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (common); 
near Lenuds Ferry, South Carolina (common). 
Cotypes. — Cat. No. 64200, U.S.N.M. 
PERIGASTRELLA DEPRESSA, new species. 
Plate 73, figs. 10-13. 
Description. — The zoarium incrusts bryozoa and shells. The zooecia are 
very little elongated, distinct, irregularly hexagonal ; the frontal is little convex, 
bordered by very small areolae, and formed of a nearly smooth pleurocvst detach- 
able from the subjacent olocyst. The apertura is semilunar, transverse, with a 
straight or slightly convex proximal border; the peristome is scarcely salient; its 
proximal border is depressed , never salient, sometimes inclined toward the aper- 
tura. The ov;cell is large, smooth, partially fixed to the distal zooecium: its orifice 
is little visible exteriorly. 
Measurements. — Apertura 
Variations. — The zooecial form of this species is rather variable and can not 
serve for determination. The areolae are invisible most of the time ; only the 
perfect specimens are provided with them. But the essential characters of this 
species are easy to recognize ; orifice of the ovicell invisible, entire absence of salient 
labial mucro. 
Affinities. — This species much resembles Perigastrella trapezoidea ; it differs 
from it in its still flatter frontal, in the absence of a salient labial mucro, and in its 
almost smooth zooecia. 
It differs from Hemicyclopora parajuncta in its areolae, sometimes visible, in 
the absence of labial mucro, and in its ovicell, which is better attached, more fixed 
to the distal zooecium. 
O ccurrence. — Middle Jacksonian : Wilmington, North Carolina (common) ; near 
Lenuds Ferry, South Carolina (rare). 
Cotypes. — Cat. No. 64201, U.S.N.M. 
PERIGASTRELLA RECTILINEATA, new species. 
Plate 73, figs. 14-19. 
Description. — The zoarium incrusts shells and bryozoa; the zooecia'are disposed 
in linear rows. The zooecia are distinct, elongated, elliptical ; the frontal is smooth, 
7i(t= 0.06—0.08 mm. . |7i«=0.50mm. 
?a=0.12-0.14 mm. ' ,OOeCUim l73=0.40-0.50 mm. 
