CORALS AND BRYOZOA. 
177 
vated, angular or rounded, forming polygonal areas inclosing the cell aper¬ 
tures, length about .45 mm., width one-half the length. There are compara¬ 
tively prominent, conical nodes at the angles of the elevations; when the 
frond is well preserved the elevations are rounded and strongly granulose; 
when a little worn or macerated they are acutely angular and the granules 
are minute. 
This species has a general resemblance to T. (0.) subquadrata and T. (0.) 
hexagona; from the former it is distinguished by the stronger branches, the 
larger cell apertures and the larger and more elongate vestibular areas; from 
the latter by the somewhat larger cell apertures and vestibular areas, and by 
the more prominent nodes at the angles of the elevations, and the smaller 
granules: from T. ( 0 .) nexa it is distinguished by its larger cell apertures and 
much stronger angular elevations between them, and their more irregular 
disposition. 
Formation and locality. Hamilton group, West Hamburg, Erie county, N. Y. 
Trematopoiia (Ortiiopora) subquadrata. 
PLATE LV, FIG. 10; AND PLATE LVI, FIGS. I,f,. 
• Tir.inatopora subquadrata, Hall. Trans. Albany Institute, vol. x, p. 181. 1S81. 
“ “ “ Report of State Geologist for 1583, p. 11. 1884. 
Zoarium ramose, solid; bifurcations infrequent; branches widely diverging, 
diameter about 1.25 mm. Cells tubular, arising from the center of the 
branch, length a little less than 1.50 mm., for the greater portion of their 
length oblique, straight, curving outward near the surface, in contact for 
nearly their entire length, slightly separating as they approach the surface; 
cell walls apparently corrugated ; septa very thin and infrequent. Cell aper¬ 
tures oval, length about .18 mm., width one-half the length, very closely and 
sometimes irregularly disposed, but usually in longitudinal, parallel rows, 
alternating and forming oblique transverse rows, having an angle of about 
forty-live degrees to the axis of the branch, the latter arrangement the most 
conspicuous. Peristomes obsolete. The narrow space between the cell 
apertures is elevated, sharply angular, enclosing the apertures in a rliomboidal, 
