258 PALEONTOLOGY OF NEW YORK. 



transverse section lenticular or flattened oval, greatest thickness about .50 

 mm. ; bifurcations frequent, branches widely diverging. Cells tubular, aris- 

 ing obliquely from the inesotheca, curving and oiiening directly outward. 

 Intercellular tissue consisting of irregularly disposed vesicles. Cell apertures 

 oval, length a little moi-e thcan .25 mm., width a little less than two-thirds 

 the length, disposed in longitudinal lines, separated by from once and one- 

 half to twice the length of an aperture, usually having the appearance 

 of being irregularly disposed ; transversely the apertures are very frequently 

 in contact. Peristomes moderately thick, distinctly and equally elevated, 

 not denticulated ; when well preserved the summits have from seven to ten 

 minute nodes or granules. The interapertural space is marked by interrupted 

 longitudinal striations, of about the same thickness and height as the peri- 

 stomes, which frequently somewhat obscure the cell apertures. When well 



preserved these strise are granulose; granules similar to those of the peristomes. 



********* 



Formation and locality. Hamilton group, Darien Centre, N. Y. 



Stictopoea permarginata. 



PLATE LXm, FIG. 16. 



8tietopora permarginata. Ham. Trans. Albany Institute, vol. x, p. 191. 1881. 

 " " " Report of State Geologist for 1883, p. 46. 1884. 



ZoARiUM consisting of flattened, dichotomously branched fronds, arising from a 

 spreading base, or from rootlets attached to foreign bodies. Branches from 

 1.25 to 1.75 mm. in width, with parallel margins, not expanding before bifur- 

 cating; non-celluliferous marginal space extremely narrow or obsolete; trans- 

 verse section broadly lenticular or oval, greatest thickness .75 mm. ; marginal 

 angles not acute ; bifurcations infrequent, sometimes occurring at intervals 

 of 15 mm. or more ; branches diverging at an angle of about sixty degrees. 

 Cells tubular, gradually enlarging to the aperture ; for about one-half their 

 length nearly parallel with the mesotheca, then abruptly turning and opening 

 outward. Intercellular tissue consisting of irregularly disposed vesicles. 

 Cell apertures oval, length .25 or .30 mm., width about one-half the length, 



