BRYOZOA—CRYPTOSTOMATA. 



157 



peristomes, and with interspaces marked by variously disposed 

 thread-like ridges and a row of minute papillae. Ord. 



Fig. 210. Clathropora frondosa, with portions of eel luliferous face enlarged. (Hall.) 



132. A. simplex Ulrich. (Fig. 208, £•.) Ordovicic. 

 Jointed, but generally found in isolated unbranched segments, 



12 to 19 mm. long and I to 1.8 mm. wide; margins free from 

 apertures; longitudinal wavy and papillose ridges, alternately con- 

 verging and diverging, surround the apertures. 



Stones River and Black River of Minnesota and Iowa. 



133. A. shafferi Meek. Ordovicic. 

 Segments flat, branching repeatedly ; apertures oval, rather dis- 

 tant ; interspaces with from one to four wavy raised lines, visible 

 under high power. 



Lorraine of the Cincinnati region. 



LXXVII. Stictoporella Ulrich. 

 Branching and leaf-like, nonarticulate from spreading base ; 

 zocecia on both sides, with primitive portion tubular, usually long, 

 generally without any septa, except occasionally an inferior one ; 

 orifices at bottom of wide sloping vestibule ; thick walled, untabu- 

 lated mesopores on margins of frond and between apertures. Ord. 



134. S. cribrosa Ulrich. (Fig. 208, h). Ordovicic. 

 Fenestrules at irregular intervals and varying greatly in size and 



form ; apertures small, subcircular or elliptical, with sharply defined 



