96 
PALEONTOLOGY OF NEW YORK. 
boiclal peristome. There are also frequent short, interrupted striations 
between the cell apertures. 
The characteristics of this species are so well defined that it will be readily 
distinguished from any other. 
Formation and locality. Upper Helderberg group, west of Le Roy, N. Y. 
Stictopora perarcta. 
PLATE XXIX, FIGS. 37, 38. 
Stictop/ora perarcta, Hall. Trans. Albany Institute, vol. x, abstract, p. 15. 18S1. 
*■ •• “ Reportof State Geologist for 1885, advance sheets. Expl. pi. 29, figs. 37, 38. 1886. 
Zoarium consisting of a flattened, bifurcating stipe ; width of branches slightly 
less than 1 mm., margins parallel; transverse section lenticular; greatest 
thickness about .40 mm. Cell apertures oval, length .20 mm., width from 
one-half to three-fourths the length; disposed in longitudinal parallel rows, 
which are separated by prominent ridges; five ranges on each face of the 
branch. Peristomes thin, very slightly elevated. 
This species may be distinguished from S. linearis by its larger, oval cell 
apertures. 
Formation and locality. Upper Helderberg group, Onondaga valley, Onondaga 
county, N. Y. 
Stictopora linearis. 
PLATE XXVIII, FIGS, i, 5; and PLATE XXVII, FIG. 1. 
Stictopora linearis , Hall. Trans. Albany Institute, vol. x, abstract, p. 15. 1SS1. 
“ “ Report of State Geologist for 1882. Expl. pi. 25, figs. 4. 5. 1883. 
“ rectilatera (in error). Report of State Geologist for 1885, advance sheets. Expl. pi. 27, fig. 1. 
1886. 
Zoarium consisting of a flattened, dichotomously branching stipe; transverse 
section lenticular; width of branches 1.50 mm., margins parallel; greatest 
thickness .50 mm. Cell apertures circular, diameter .20 mm.; disposed in 
longitudinal parallel rows, five or six rows on each face of a branch. Peris¬ 
tomes thin, slightly and equally elevated. Rows separated by a narrow ridge. 
This species may be distinguished by its narrow branches, with infrequent 
bifurcations and circular cell apertures. 
Formation and locality. Upper Helderberg group, N. Y. 
