CORALS AND BRYOZOA. 
185 
This species most nearly resembles T. (0.) immersa, but may be distinguished 
by its smaller and more closely disposed cell apertures: from T. ( 0 .) hexagona 
it differs as follows; the cell apertures are smaller, the elevations between 
them are less angular, and do not have a regular row of nodes or grannies 
along the middle; from T. ( 0.) subquadrala it is distinguished by the fewer 
ranges of cell apertures on a branch, their somewhat more regular disposition, 
the wider and less angular elevations between the cell apertures, and the more 
irregular disposition of the nodes on the surface. 
Formation and locality. Hamilton group, Railroad station near Geneseo, N. Y. 
Trematopora (Orthopora) immersa, n. sp. 
PLATE LVI, FIG. 11. 
Zoarium ramose ; bifurcations infrequent. Cells tubular, arising from the center 
of the branch. Cell apertures oval, length about .20 mm., width from one-third 
to one-half the length, disposed in longitudinal rows, alternating and forming 
oblique transverse rows. Peristomes obsolete. Surface between the longi¬ 
tudinal rows of apertures elevated, forming prominent ridges, slightly 
narrower than the cell apertures; at the base of each aperture there is a 
comparatively prominent, conical node, and also a minute shallow pit. 
This species most nearly resembles T. (0.) carinata, but may be distinguished 
as follows ; the branches are somewhat larger, the ranges of apertures are more 
numerous, the longitudinal ridges are not so prominent and are somewhat 
irregular; the oblique transverse rows of apertures are much more conspicuous 
than in that species, the transverse space between the apertures is much less 
depressed: from T. (0.) ornata it is distinguished by its somewhat larger cell 
apertures, the more prominent longitudinal ridges, the fewer ranges of cell aper¬ 
tures on a branch, the more prominent nodes and their more regular disposition ; 
the oblique transverse rows of apertures are much less conspicuous: from 
T. (0.) bispinulata by the stronger, more prominent, longitudinal ridges and 
more irregular disposition of the cell apertures 
Formation and locality. Hamilton group, Darien Centre, Genesee county, N. Y. 
