206 DlClTOSPONGIDA 



PLATE IV. 

 HYDRIODICTYA, gen. nov. 



Page 77. 

 (SeePlatesV, XVI, XXI.) 



Hydbiodictya patula, Hall (sp.). 



Page 78. 



Figure 1. A view of the original specimen ; showing the smooth, expanding 

 surface, regular aperture and sharply defined reticulation. 

 Chemung group. Brown hill, near ColiocUni, N. Y. 



HYDNOCERAS, Conrad. 



Tape 05. 

 (Seo Plates II, III, V, VI, VII, VIII, IX, X, XI. XII, XXXIII, XXXVI, XXXVII, XXXVIII, XXXIX, XLVI ) 



Hydnoceras tuberosum, Conrad. 



Piigo 97. 

 (See Plates 11, III, V, VI, VII, VIII, XXXVIII.) 



Figure 2. A plaster-cast of the original specimen of the sj^ecies. 



Chemung group. Said to have come from near AMlson, Steuben 

 county, New Yovh. 



Figure 3. A very hroad and somewhat compressed example with the reticu- 

 lation and subprismatic form finely preserved. 



Figure 4. A small specimen with the normal number of four horizontal rows 

 of low nodes, the summit of each of which is incomplete, indicating 

 the presence of spicular tufts at these points. The specimen lies in its 

 matrix, which retains the impressions of the pointed tufts on the 

 lateral nodes and the vertical, erect expansions connecting them. 

 These were probably also present in varying degrees of development 

 on all of the principal vertical and horizontal spicular bands. An 

 interesting abnormality is shown on the lo\ver right margin of the 

 specimen Avhere a very strong spicular tuft exists between two nodes 

 in their normal j^osition, and there is only very obscure evidence of 

 an intercalary node at this point. The tuft near the base of the 

 sponge represents another very faintly developed node. 

 Chemung group. Brown hill, near Cohocton, New Yorh. 



