230 DlCTYOSPONGID^ 



PLATE XVI. 

 RHABDOSISPONGIA, gen. nov. 



Page 116. 

 (See Plate XLVII.) 



Rhabdosispongia Amalthea, Hall (sp.). 



Page 116. 



Figure 1. A nearly entire individual with broad annulations and sharp 

 vertical ridges. Drawn from a plaster cast of the original specimen 

 which was from the 

 Chemung group. Great Bend, Susquelmnna county, Pennsylvania. 



HYDRIODICTYA, gen. nov. 



Page 77. 

 (See Plates IV, V, XXI.) 



Htdriodictta cylix, sp. nov. 



Page 78. 

 (See Plate V.) 



Figure 2. The external impression of a large individual somewhat crumpled 

 by compression ; showing the prevailing coarse and square meshes 

 of the reticulum. Near the middle of the sponge a break in the 

 net-work has been repaired by highly irregular spicular bands. 

 Chemung group. Deyo hasin, Naples, New York. 



DICTYOSPONGIA, gen. nov. 



Page 72. 

 (See Plates XIV, XV, XXVII, XXXIII, XXXVI, XXXVIII, XLI, XLII, XLIV, XLVI, LV, LVI, LXI.) 



DiCTYOSPONGIA SCEPTUUM, Hall (sp.). 

 Pago 73. 

 (See Plates XIV, XV, XXVII, XXXVI.) 



Figures 3, 4. Opposite sides of a slender but imperfect Sf)eciraen ; showing 

 a difference in the preservation of the reticulum. In figure 4, the 

 exposed side is a shai-p internal cast and clearly shows the elongate 

 rectangles produced by the intersection of the primary lamellae, 

 while the surface represented in figure 3 is involved in a muddy or 

 shaly sediment which has retained the finer net-work of the outer 

 wall. 

 Chemung group. Friendsliijy, New Yorh. 



