BRYOZOA. 521 



number of these minute tubuli. Superior hemiseptum very pro- 

 nounced. This form in common with some others shows a 

 secondary layer growing upon the primary layer of cells, but 

 growing in reversed order, zocecium above zooecium, and macula? 

 above maculae. This is best observed in longitudinal sections 

 (fig. 4c). 



Externally this species resembles E. multipora Hall, but the 

 cell apertures are more rounded, and the internal structure 

 is very different. Internally it is considerably like E. montifera, 

 but the pronounced monticules of that species are sufficient 

 without other points of difference to distinguish the two. 



Position and locality: Trenton group; Port au Gres, Calhoun 

 Co., 111. 



EURYDICTYA MONTIFERA Ulrich. 

 PL XXX, Fig. 3-3d. 



, Zoarium an expanded frond, several cm. in height and breadth 

 and 0.15 to 0.20 mm. in thickness. Surface provided with con- 

 spicuous monticules having solid apices, and with no marked 

 arrangement, two or three mm. apart. Primitive portion of 

 zooecia very short, vestibular portion of tube almost at right 

 angles with the surface. Vestibules 0.15 to 0.18 mm. in diame- 

 ter, inter- vestibular space about the same as the diameter of the 

 vestibules. Apertures oval, from 0.15 to 0.22 (nm. in'their long 

 diameter, nine longitudinally and ten diagonally in three mm., 

 arranged in longitudinal and diagonally intersecting series. 

 Zooecia surrounded by a single row which sometimes becomes 

 doubled at the angles, of minute tubuli, appearing on the 

 surface as granules. The macula? are composed of a large num- 

 ber of these minute tubuli having an indefinite radial arrange- 

 ment. Occasionally there is a superposed layer growing in the 

 reversed direction. Superior hemiseptum rather pronounced. 



In some respects this species is closely related to E. calhoun- 

 ensis, but is readily distinguished from that form by the smaller, 

 and differently arranged median tubuli and the montiferous 

 surface. The zocecia of that species also have a dark band sur- 

 rounding the visceral cavity; this band is wanting in E. monti- 

 fera. 



Position and locality: Cincinnati group, Wilmington, 111. 

 65 



