236 DiCTTOSPONGIDiE. 



PLATE XIX. 

 PRISMODICTYA, gen. nov. 



Page 79. 

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



Prismodictya choanea, sp. nov. 



Page 85. 

 (See Plates XXVII and XXXV.) 



Figure 1. The basal portion of a specimen of medium size, showing a fine 

 reticulum and faint traces of prism-faces. 



Figure 2. A similar portion of a larger specimen. 



Chemung group. Iscliua, Cattaraugus county, New Yorh. 



Figure 3. The upper portion of a large cup, believed to represent this 

 species; having the prism-faces obsolescent and an extremely fine 

 reticulum. This specimen is accompanied by fragments of others 

 of the same species and impressions of the brachiopod, Spirifer 

 dhjunctiis. 

 Chemung group. Almond, Allegany county, New York. 



PlilSMODICTYA PARALLELA, Hall (sp.). 



Page 82. 



(See Plates XX, XXI, XXXV.) 



Figure 4. The exterior of a portion of a cup, showing its gradual expansion, 

 the somewhat obscure and rounded prism-faces and the sharply 

 elevated primary reticular bands. This is drawn from a plaster- 

 cast of the original specimen, which is an external impression in 

 sandstone. 



Chemung group. Southwestern New Yorh (^frecise locality 

 unhnoi07i). 



Pkismodictya Conradi, Hall (sp.). 



Page 91. 

 (See Plate XVIII.) 



Figure 5. An apical view of the basal extremity of the specimen shown on 



plate 18, figure 4. 

 Figure 6. Side view of the same specimen presenting its narrower diameter 



and showing the irregular node at the top. 



Chemung group. Randolph, Cattaraugus county, New Yorh. 



