CORALS AND BRYOZOA. 247 



parallel, at other times slightly diverging, the greatest increase in width in 

 a length of 15 mm, being 1 mm. ; non-celluliferous marginal space narrow, 

 width .25 mm., not flat ; transverse section regularly convex on the two sides, 

 greatest thickness .50 mm.; bifurcations comparatively distant; branches 

 diverging at an angle of sixty degrees or more. Cells tubular, for the greater 

 portion of their length very oblique, often nearly parallel to the mesotheca, 

 then turning and opening a little obliquely to the surface, on the narrower 

 portion of the branches frequently recumbent for nearly their entire length. 

 Intercellular tissue vesiculose ; vesicles irregularly disposed, more compactly 

 arranged near the surface than below. Cell apertures very broadly oval, 

 often circular, sometimes slightly pustuliform, length .25 mm., width from 

 .18 to '.25 mm, disposed in somewhat irregular longitudinal rows, but the 

 rows being very clo.se together and the apertures forming them being sepa- 

 rated by more than twice their diameter, the arrangement is indistinct; they 

 sometimes alternate and form oblique transverse rows, and often irregular, 

 direct transverse rows; the apertures forming these are closely disposed, 

 generally nearly or quite in contact ; the marginal apertures are very little, 

 if at all larger than the others. Peristomes moderately thick, strongly ele- 

 vated, the posterior portion being the most prominent, not denticulated, 

 smooth. Interapertural and marginal space striated ; striaB short, tortuous, 

 interrupted, length from .25 to 1 mm., from eight to ten in the space of 

 1 mm. mejisured transversely ; they are abruptly rounded, slightly elevated, 



the peristomes being very prominent above them. 



* * »* « * * * * 



Formation and locality. Hamilton group, Ontario county, N. Y, 



Stictopoba sinuosa. 



PLATE LXI, FIG. 17. 



Stictopora siniu)sa. Hall. Trans. Albany Institute, vol. x, p. 190. 1881. 



Report of State Geologist for 1883, p. 42. 1884. 



ZoARiOM consisting of a flattened, dichotomously branched frond of somewhat 

 rigid appearance; bifurcations occurring at intervals of about 7 mm. 



