172 DlCTYOSPONGID^ 



There are no horizontal bands corresponding with these vertical bundles 

 The rest of the skeleton is pretty much lost ; here and there a few interlacing 

 horizontal spicules are to be found at the intersections, but the broad vertical 

 interspaces are regularly divided by impressions of small quadrules which 

 measure from 2 to 3 mm. on a side, without further evidence of coarser mark- 

 ings. At one side of the specimen the edge of the cup is exposed and shows 

 the fact that the interstitial vertical and cross spicules projected for a short 

 distance beyond the surface of the cup, and also that at wide intervals there 

 were small projecting tufts similar to those in Physospongia. 



In the matrix taken from the interspaces between the lateralia have been 

 found large echinate hexactins or pentactins with curved arms, also some 

 minute hexactins and micrumbels. 



Dimensions. The single known specimen of this species has a length of 

 98 mm. and a maximum width of 105 mm. 



Locality. In the calcareous shales of the Keokuk group, Crawfords- 

 ville, Indiana. 



PHRAGMODICTYA, HaU. 



1881. Dictyophyton, Whitfield. Bull. No. 1, Amer. Mus. Nat. Hist., p. 18. 



1882. Phragniodictya, Hall. Notes on the Family Dictyospongidse ; Expl 



pis. 17, 19, 20. 

 1884. Phragmodictya, Hall. Thirty-fifth Ann. Kept. N. Y. State Mus. Nat. 

 Hist., pp. 466, 477, 478. 



Sub-cylindrical or slightly expanding cups abruptly contracted at the 

 base to form a smooth, broadly obconical or nearly transverse plate or 

 diaphragm. The edge of this basal plate bears a broad peripheral frill. 

 Attachment was probably effected both at the apex of the diaphragm and by 

 the basal frill. Surface covered with vertical ridges and nodes. Reticulum 

 very fine and without tufts. 



Type, Phragmodictya catillij'ormis, Whitfield (sp.). 



This genus differs from TirrsAKODioTYA in the absence of a coarse regular 

 quadration and fenestration of the surface and in the distinctly radiate net- 

 work of the basal diaphragm, and from Aclceodictya in the convergence of the 

 radial bands of the diaphragm to a well-defined and probably tufted apex. 



