CORALS AND BRYOZOA. 259 



closely and irregularly disposed, often in contact, sometimes forming very 

 irregular transverse rows ; apertures forming the rows with their margins in 

 contact. Peristomes comparatively very thick, converging, equally elevated, 

 not denticulated, when well preserved having several conspicuous nodes or 

 granules. On the interapertural space there are occasional short, inter- 

 rupted, granulose striations of the same strength as the peristomes. 



This species, under different conditions of preservation, varies much in 

 appearance. When the frond is well preserved the apertures are indistinct, 

 being obscured by the nodes, but when macerated, so that the nodes are obso- 

 lete, the apertures are very conspicuous ; when still further macerated the 

 vesicles are seen, appearing as angular pits between the cell apertures. The 

 apertures are sometimes so arranged . that the peristomes give to the surface 

 a striated appearance. 



********* 



Formation and locality. Hamilton group. West Hamburg, Erie county, N. Y. 



Stictopora interstriata. 



PLATK LXn, FIGS. 7-12. 



Stictopora interstriata. Hail. Trans. Albany Institute, vol. x, p. 191. 1881. 

 " " " Report of State Geologist for 1883, p. 45. 1884. 



ZoARiOM consisting of a flattened, dichotomously branched frond. Branches 

 2.50 mm. in width, with essentially parallel margins, scarcely enlarging 

 before bifurcation ; non-celluliferous marginal space .33 mm. wide ; trans- 

 verse section lenticular, angles very acute, greatest thickness observed 

 .65 mm. ; the bifurcations usually occur at intervals of from 10 to 20 mm., 

 but on one specimen, which in all other respects is similar to the ordinary 

 forms, they occur at intervals of 5 or 6 mm. Cells tubular, for the greater 

 portion of their length recumbent, then turning abruptly and opening 

 directly outward. Cell apertures oval, length about .30 mm., width a little 

 more than one-half the length, disposed in longitudinal rows, the apertures 

 being separated by one and one-half times their diameter the arrangement 

 is indistinct; they often form irregular, transverse rows, the apertures of 



