476 THIRTV -FIFTH EEPORT ON" THE STATE MUSEUM. 



Surface closely reticulated by strong radiating and concentric strise, 

 which are somewhat irregular in their arrangement. » Margin plicate 

 or subnodose. The disc is likewise marked by distant stronger striae 

 dividing the surface into larger quadrules, but their regular recurrence 

 cannot be determined over the entire surface. The specimen preserves 

 but a single surface, and is a part of a subcircular discoid form lying 

 upon the nearly plane surface of the matrix, and parallel to the lines 

 of bedding, as shown by the ripple-marks upon the opposite side. 



The fragment described has a diameter of 145 mm. 



Formation and locality. In sandstone of the Waverly group, at 

 Warren, Pa. 



ECTENODICTYA BURLIKGTOKENSIS, 71. Sp. 



Frond flabellate or explanate. 



Surface reticulate by radiating and concentric striae. The concen- 

 tric striae are nearly equidistant, about two in the space of three mm. 

 The radiating striae are somewhat more distant ; between each pair of 

 these are quadrules of finer reticulations. The radiating striae are 

 sometimes fasciculate and irregular, the fascicles dispersing and their 

 individuality lost toward the outer margin. 



The fragment described has a length of about 150 mm., the greatest 

 width at the outer extremity is about 120 mm. 



Formation and locality. In the yellow sandstones below the lime- 

 stone, at Burlington, Iowa. 



ECTENOD1CTYA ECCENTRICA. 



Plate 20, Fig. 1. 



Phragmodictya eccentrica, Hall. Notes on the Family Dictyospongidse ; pre- 

 lim, for the 35th Kept, pi. 19, fig. 1. 1-882. 



Discoid, with the margins incurved ; or forming shallow saucer- 

 shaped fronds. 



Surface marked by radiating and concentric striae, with the inter- 

 mediate spaces finely reticulate. Toward the periphery the surface 

 shows undulations, with a tendency to plication. 



A small specimen has a diameter of about 85 mm. 



Formation and locality. In the calcareous shales of the Keokuk 

 group ; Crawfordsville, Ind. 



Ltrodictya Romihgeri, n. sp. 



Cup infundibuliform or flabelliform ; entire frond unknown. 



Surface reticulate by strong radiating and concentric striae, which 

 are subequidistant and closely arranged, dividing the entire surface 

 into smaller quadrules of finer reticulations. The surface is also 

 divided into longitudinal areas about 15 mm. in width, limited by 

 strong radiating bauds of spicules. 



