CORALS AND BRYOZOA. 
19 
Trematopora (Orti-iopora) parallela. 
PLATE XI, FIGS. 13, 14 ; AND PLATE XXIII, FIGS. 7, 8. 
Trematopora ‘parallela, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 152. 1S79. 
“ ? “ “ Report of State Geologist for 18S2. Expl.pl. 11, figs. 13, 14. 18S3. 
Zoarium ramose, solid; bifurcations infrequent; diameter of branches 1 mm. 
Cells tubular, arising from the center of the branch, gradually curving to the 
surface. Apertures oval, length .20 mm., width from .12 to .15 mm. : mar¬ 
gins equally elevated; arranged in quincunx, forming longitudinal parallel 
rows. Each aperture has some portion of its margin nearly or quite in 
contact with four other apertures, the margins thus forming a continuous 
elevation, which, especially when thickened by silicification, resembles a ridge 
separating the rows of apertures. At each point of contact there is a small 
spine. 
This species closely resembles some forms of T. regularis, but the peculiar 
arrangement of apertures will be sufficient to distinguish it. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
DIAMESOPORA, Hall. 1852. 
Zoarium ramose, hollow, inner surface consisting of an epitheca. Intercellular 
space solid. 
These forms differ from Trematella in having hollow branches. 
DrAMESOPORA CONSTRICTA. 
PLATE X, FIGS. 14-19 ; and PLATE XXIII A, FIG. 7. 
Trematopora constricta, Hall. Twenty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 104. 1874. 
Trematopora? “ “ Thirty-second Rept. N. Y. State Mus. Nat. Hist. p. 150. 1879. 
“ “ “ Report of State Geologist for 1SS2. Expl. pi. 10, figs. 14-19. 1883. 
Zoarium ramose; branches frequent, hollow; diameter from 2 to 4 mm. Thick¬ 
ness of the bryozoum .33 mm.; inner surface covered by an epitheca; marked 
by strong concentric undulations of growth and line striations; line longi- 
