3Qg Du TYOSPONC.ID.E. 



PLATE LV. 

 PRISMODICTYA, gen. nov. 



rage 79. 

 (See Plates XVII, XVIII, XIX, XX, XXI, XXVII, XXXIII, XXXIV, XXXV, XXXVI, XLI, XLH.) 



Pkismodictya polyiiedra, sp. nov. 



Page 168. 



Figures 1, 2. Opposite sides of the original specimen. 



Keokuk group. In the shales at Crawfordsville, Indiana. 



DICTYOSPONGIA, gen. nov. 



Page 72. 

 (See Plates XIV, XV, XVI, XXVII, XXXIII, XXXVI, XXXVI[t, XLI, XLII, XMV, XLVI, LVI, LXI ) 



DlCTYOSPONGIA CYLINDRICA, Whitfield (sp.). 

 Page 166. 



Figure 3. View of the original specimen retaining the pyritized skeleton. 

 Keokuk group. Crawfordsville, Indiana. 



ACLCEODICTYA, gen. nov. 



Pago 177. 

 (See Plates LIV, LX, LXI, LXVIII.) 



ACL(E0DICTYA MAESIPUS, Sp. UOV. 



Page 178. 



(See Plates LX, LXI, LXVIII.) 



Figure 4. Portion of the specimen with pyritized skeleton ; showing the 

 extent of one of the vertical lamellae of the outer ^vall. of the 

 sponge. 

 Keokuk group. Crawfordsville, Indiana. 



(?) Lyrodictya, Hall. 

 Figure 5. Enlargement of a part of the surface of a young sponge ^vhich 

 probably belongs to a species of this genus ; showing the pyritized 

 spicular rods of two of the vertical bundles. The quadrnles bear 

 faint traces of a fine reticulation. x3. 

 Keokuk gi-ouji. Crawfordsville, Indiana. 



