I48 NEW YORK STATE MUSEUM 



careous material or sclerenchyma, which increases in amount 

 toward the calyxes. Calyxes in the form of circular apertures sur- 

 rounded by a cup-shaped, thickened margin, the floor of which 

 is striated by rudimentary septal ridges. Septal spines in vertical 

 rows occasionally present. Tabulae few, widely separated, but ex- 

 tending completely across. Mural pores comparatively numerous, 

 circular, and irregularly distributed. 



Striatopora flexuosa Hall (Fig. 45) (1852. Pal. N. Y. 2:156, 

 pi. 40B) 



Distinguishing characters. Bifurcating or irregularly ramose 

 stems with teretely terminating branches; calyxes circular, sur- 

 rounded by large depressed cells, polygonal in outline and bounded 

 by angular ridges ; calycinal orifice in lower part of polygonal cell, 

 vertically striate, the stria continuing upward in the surrounding 

 cell. 





Fig. 45 Striatopora flexuosa with an enlargement of several calyxes 



Found not uncommonly in the Bryozoan bed of the Rochester 

 shale at Niagara, generally well weathered out. Also in the same 

 shale at Lockport (Hall). 



Class CYSTOIDEA von Buch 



The cystoids are entirely extinct marine invertebrates which 

 flourished only during Paleozoic time. Most of them lived during 

 the Ordovicic or Siluric eras, but Cambric and Carbonic forms 

 are also known. They were mostly stemmed organisms with a 

 calyx and imperfect arms like the crinoids, but a few of them were 

 stemless. The calyx, which varies in form, is composed of poly- 

 gonal plates which are united by close sutures. The plates vary 

 in number in different species, from 13 to several hundred, and only 

 exceptionally exhibit a regular arrangement. A radial arrange- 

 ment of plates, like that of the Crinoidea occurs rarely, and the 



