514 PALEONTOLOGY OF ILLINOIS. 



"cups." The principal ridges at any rate, always correspond 

 with a depression 011 the opposite side, and have a more or 

 less decided longitudinal arrangement. The cups, especialty the 

 central ones, are several times longer than wide, both dimen- 

 sions being very variable in even the same example. Generally 

 those near the lateral margins of the zoarium are shorter and 

 directed outward. The length of the depressions so far as ob- 

 served, varies from 4 to 30 mm., the width from 3 to 7 mm., 

 the depth from 1 to 2.5 mm. Summit of ridges sharp, and 

 non-poriferous. Surface of cups with rather inconspicuous 

 elongated maculae, which are somewhat depressed and best 

 shown in the examples with the shortest cups. Zooecia with 

 sub-circular apertures, surrounded by an. unequally elevated 

 peristorne, about 0.18 mm. in diameter, an equal or less dis- 

 tance apart, and averaging eight in three mm., with no recog- 

 nizable plan of arrangement. Zooecial tubes with thin walls, at 

 first prostrate along the mesial plate and somewhat flattened, 

 then bending with a moderate curve and becoming rounded, 

 proceed to the surface at an angle varying somewhat from the 

 perpendicular. A few diaphragms occasionally developed in the 

 tubes. Lunarium present but not always showing plainly. Ve- 

 sicles variable in shape and size, shallow, their width almost 

 equal to the diameter of the tubes, those along the median 

 lamina larger than the others. There is a thin deposit of light 

 colored sclerenchyma upon their floors. 



In its typical form this species is readily distinguished from 

 all the others by the elongated "cups." The two forms next 

 described are likewise easily recognized when typical, but as \ve 

 sometimes meet with examples which seem to combine the char- 

 acters of two or even all three, I have thought it best to indi- 

 cate their intimate relations by giving them only the rank of 

 varieties under G. sageneUa. 



Position and locality: Keokuk group, at Bentonsport, Iowa; 

 Warsaw beds, at Warsaw, 111. 



GLYPTOPORA SAGENELLA var. CALICULOSA Ulrich. 



(Not figured.) 



In this variety the zoarium is wider, more lax, and has a 

 more delicate aspect than in the typical form of G. sagenella, the 



