446 PALAEONTOLOGY OF ILLINOIS, 



var. CONFERTA Ulrich. 



PL LXXIII, Fig. 9-9a. 



This variety has the beads of the moniliform walls more 

 closely set, there being in the peripheral region ten or eleven in 

 one mm. The moniliform character of the walls is more pro- 

 nounced in this variety than in any other form of the genus 

 known to me, excepting S. ohioensis Foerste, lately described 

 from the base of the Coal Measures in Ohio. Should it prove 

 upon further examination that the var. conferta is identical 

 with the Ohio form, then Mr. Foerste's name will take prece- 

 dence over mine. 



Position and locality: Coal Measures; both the varieties and 

 the typical form, occur at Caseyville, 111. I have also studied 

 examples from Ohio, and from Lawrence, Kansas. 



STENOPORA? SIGNATA Ulrich. 



PI. LXXIII, fig. 5, 5b. 



Zoarium consisting of branching cylindrical stems, from four 

 to seven mm. in diameter. Surface hirsute, without monticules 

 Zocecial apertures small, sub-circular or sub-polygonal, varying 

 in diameter from 0.15 to 0.25 mm.; about seven in two mm. 

 Interspaces moderately thick, minutely granulose between the 

 strong acanthopores which occur at many of the angles. Zooecial 

 tubes curving gradually from the center of the axial region to 

 the surface, where they are direct. Walls thin in the axial re- 

 gion, considerably and irregularly thickened in the cortical re- 

 gion, never distinctly moniliform. Diaphragms entirely wanting. 

 Acanthopores very large, about one to every two zooecia. Sec- 

 tions present a peculiar feature. In tangential sections, for in- 

 stance, the zocecial cavity is surrounded by a single series of 

 very minute dark spots. Along the middle of the partition be- 

 tween the zooecia the same kind of spots form closely arranged 

 stellate clusters, of five or more, while a single series again 

 surrounds the acanthopores. In vertical sections these peculiar 

 spots are closely arranged in transverse series and less regu- 

 larly in vertical rows. At the surface they appear as granules. 

 I am unable to offer a satisfactory explanation of these singu- 

 lar structures. It is possible, however, that they represent the 



