478 Thirty-fifth Eepokt on the State Museum. 



The dimensions are extremely variable. A small cylindrical speci- 

 men, somewhat compressed, with a length of 90 mm.', has a diameter 

 near the top of 30 mm., and within one-fourth of its length from 

 the upper extremity the diameter is 33. A compressed specimen of 

 medium size has a height of 100 mm., a diameter at the diaphragm 

 of 65 mm. and at the other extremity 78 mm. 



The largest specimen seen is obliquely compressed, has a diameter 

 at the septum of 135 mm., and at the top (which is incomplete at the 

 margin) the width is over 200 mm. The smallest diaphragm measures 

 about 16 mm., and there are many between this size and 100 mm. 

 The largest diaphragm measures 125 mm. in its greatest diameter, and 

 95 mm. in the transverse diameter, and the same specimen, including 

 the expanded border, measures in its greatest diameter 185 mm., and 

 in its transverse diameter 150 mm. 



Formation and locality. In the shales of the Keokuk group ; 

 Crawfordsville, Ind. 



Phragmodictya lineata. 



Plate 21, Fig. 8. 



Phragmoclictya lineata, Hall. Notes on the Family Dictyospongidae ; prelim, 

 for the 35th Kept., pi. 20, fig. 8. 1882. 



The specimen is a flattened cylindrical body, having a length about 

 three times its width. One extremity is truncated by a convex septum 

 with a strong excentric cicatrice. 



Surface rather coarsely reticulate, the longitudinal and transverse 

 striae being of nearly equal strength, and nodose at their intersection. 



The length of the fragment is 65 mm., width across the septum 25 

 mm., width in the middle of its length about 20 mm. 



This species differs from P. catilliformis in its much smaller size, 

 more convex septum, stronger reticulating striae and absence of nodes 

 or ridges. 



Formation and locality. Keokuk group ; Crawfordsville, Ind. 



Phragmodictya patelliformis, n. sp. 



The specimen described is a septum of a species of this genus, pre- 

 serving some small portions of the cylindrical body or cup. Form 

 ovate, patelliform ; apex excentric; longitudinal diameter one-seventh 

 greater than the transverse diameter. 



Surface radiatingly striate from the apex ; striae increasing in num- 

 ber and strength as they approach the margin. Fine radiating and 

 concentric striae reticulate the surface; with stronger radii composed of 

 fascicles of finer striae, which become nodose toward the periphery. 



The greatest length of the septum is 135 mm. and the greatest 

 width is 115 mm. The length from the cicatrice to the distal margin 

 is 100 mm., the transverse diameter through the apex is 100 mm. 



Formation and locality. In the calcareous shales of the Keokuk 

 group; Crawfordsville, Ind. 



