304 DurryosPONoii)^. 



PLATE LIII. 

 THAMNODICTYA, Hall. 



Page 160. 

 (See Plates L and LII.) 



TlIAMNODICTYA OrTONI, Sp. nOV. 

 Page 162. 



Figures 1, 2. Opposite sides of a specimen whicli is an internal cast of the 

 expanded apertural portion of the sponge, the smooth lower point 

 representing the place of attachment of the pedicel. The species is 

 characterized by the fineness of the reticulation, the peculiar curva- 

 ture of the vertical bands and its large size. 

 Waverly group. Moo^s Ran, Licking county, Ohio. 



TIIYSANODICTYA, gen. nov. 



« Page 126. 



(Sea Plates XIX, XXIII, XXIV, XXV, XXVI, XXVII, XXXVIII, XXXIX, XL, XLII.) 



TlIYSANODICTYA EXPANSA, Hall (sp.). 

 Page 154. 



Figure 3. A large basal disc or diaphragm characterized by its irregularly 

 radiating spicular bands and nodose periphery. This represents an 

 individual of great size. 

 Waverly group. Warren, Pennsylvania. 



TYLODICTYA, gen. nov. 



Page 151. 



Tylodictya ( ? ) TENUIS, Hall (sp.). 



Page 152. 



Figure 4. A small portion of a frond showing two double nodes, one more 

 distinctly divided. Drawn from a cast of the original impression. 



Figure 5. The original illustration of this species, showing the impression of 

 one of the double nodes and the extremely fine reticulation of the 

 surface, but with the specimen oriented differently than in fig. 4. 

 Waverly group. Warren, Pennsylvania. 



