CORALS AND BRYOZOA. 
193 
NEMA TAXIS, Hall. 1886. 
(See page 74.) 
Nemataxis simplex. 
PLATE LXVI, FIGS. 17-19. 
Zoarium ramose, solid; bifurcations very infrequent; branches 1.50 mm. in 
diameter. Cells tubular, arising from the center of the branch, oblique, 
making a sinuous curve, in contact for the greater portion of their length, 
separating at a very short distance from the surface. Cell apertures oval, 
length about .16 mm., width two-thirds the length, disposed in parallel, 
longitudinal rows; sometimes alternating and forming obliquely transverse 
rows; separated by about one-half the length of the aperture, about eight¬ 
een rows on a branch. Peristomes very slight or entirely wanting. Surface 
between the apertures elevated, convex, finely granulose. In some con¬ 
ditions of weathering the peristomes are elevated and the surface between 
the cell apertures is flat. 
This species is easily distinguished from N. jibrosus of the Upper Helderberg 
group, the only other species of this genus at present known, by its much 
smaller size. The surface has some resemblance to that of Badropora grani- 
striata, but the cell apertures are much smaller, and the space between them 
much narrower. 
Formation and locality. Hamilton group, Darien Centre, Erie county, N. Y. 
BACTROPORA, nov. gen. 
Bactropora granistriata. 
PLATE LXVI, FIGS. 20-22. 
Trematopora ? granistriata, Hall. Trans. Albany Institute, vol. x, p. 182. 1SS1. 
“ “ “ Report of State Geologist for 1883, p. 13. 1884. 
Zoarium ramose, solid ; bifurcations distant; base tapering, acute at the apex, 
finely striated, striae minutely granulose. Cells tubular, arising from the center 
of the branch, oblique, curved, walls comparatively thick; septa thin and 
