Fossil Keticulate Sponges. 467 



CLEODICTYA, 71. g. 



Frond rapidly expanding from the base to a subglobose or hemi- 

 spherical form, bearing a row of large rounded nodes on the periphery; 

 tube abruptly contracted above and extending in a cylindrical or 

 slightly expanding form. 



Substance composed of a regular lattice-work of six-radiate spicules, 

 with bundles of larger acicular rods. 



PHYSOSPQNGIA, fl. g. 



Frond cylindrical or cyathiform, expanding from the base. Surface 

 divided into from eight to twenty-four longitudinal areas by bands of 

 tubular spicules, and into regular quadrules by concentric bands of 

 spicules. The surfaces of these larger quadrules are alternately ele- 

 vated and depressed, giving a bullate appearance to the cup. The 

 spicules composing the bands are very elongate rods having an anchor- 

 shaped extremity with the lateral processes much extended. Inter- 

 zonate tissue finely reticulate. The spicules of the superficial layer 

 have a radiate arrangement and are often produced into tufts or 

 spines from the summits of the bullae. 



UPHANTJENIA. 



Circular fronds composed of ligulate radiating and concentric baads, 

 with the inclosed large quadrules free from any tissue. 



The bands show fine reticulate striae similar to Dictyophyton. The 

 margins of the ligulae are thickened, probably from the aggregation 

 of spicules. 



