Desceiptioxs of Devonian Fossils. 235 



of an inch, above wliich it is irregular and seldom increases in lateral 

 dimensions. Calyx not very deep, broadly rounded at tlie bottom, and 

 more rapidly ascending near the sides. Rays distinctly marked on the 

 surface of the cup, about sixty in larger specimens. Exterior of cup 

 clear and neat, entirely covered with an epithecal coating, and very 

 distinctly marked by the costal ridges corresponding to the rays of the 

 cup; the base usually shows evidences of attachment. In a vertical 

 section the vesiculose partitions are small and numerous. 



Formation and locality. In the marly beds at Ilockford, Iowa. 



Genus — AULOPORA Goldf. 



AULOPORA SAXrVADUM U. Sp. 

 Plate 10, flg. 6. 



Bryozoum incrusting foreign bodies, in branching tubes composed of 

 a succession of separate cells ; bifurcations frequent, often at each cell ; 

 seldom more than two cells va direct succession ; angles of bifurcations 

 varying from thirty to nearly sixty degrees ; tubes about a thirtieth of 

 an inch in diameter, increasing somewhat in older specimens ; cells 

 seldom more than a tenth of an inch in length ; slender at base and 

 enlarging upward ; apertures round, slightly thickened and elevated, 

 situated near the upper end of the cell. Surface finely striated when 

 well preserved, but this feature is seldom seen. 



Formation and locality. In the marly beds at Rockford and Hack- 

 beriy, Iowa. 



AULOPOEA loWENSIS n. 8]). 

 Plate 10, flg. 5. 



Tubes robust, branching from nearly every cell, and frequently 

 coalescing with adjoining ones, so as entirely to conceal the surface 

 beneath. Cells from one-tenth to one-eighth of an inch in length, and 

 about one-twentieth of an inch in diameter, wider than high, with 

 large, round, considerably elevated apertures, which are directed 

 upward, are as wide as the greatest diameter of the cells, and are situ- 

 ated near their upper extremities. 



This species differs from the preceding in the gi-eater strength of the 

 cells and in the frequent coalescing of the tubes. 



Fcyrmation and locality. In the marly beds at Hackberry, Iowa. 



Genus— STOMATOPORA Bronn. 



(ALECTO Lam. not Leach.) 

 Stomatopora? altsrnata n. 8jp. 



Plate 10, flgs. 7, 8, 



Bryozoum consisting of a slender, irregular, bifurcating tube, giving 

 origin to small cylindrical cells on the opposite sides, in alternating 



