Explanations ok Platkh. 253 



PBISilODICTYA CHOANEA, Sp. nOV. 



Page 85. 



(See Plates XIX anil XXXV.) 



Figure 5. The lower portion of a large cup showing obscurely prismatic 

 faces. 

 Chemung group. Imhaa, Cattaraugus county, New York. 



DiCTYOSPONGIA ? (EcTENODICTTA ?). 



Figure 6. A flat and expanded portion of a frond, whose outline may 

 represent the original form of the cup, although the edges appear to 

 be somewhat ragged. The reticulation is very fine and the surface 

 without evidence of prism-faces. The specific and generic relations 

 of the' specimen are uncertain. 

 Chemung group. Wellsvllle, New YorJc. 



THYSANODICTYA, gen. nov. 



Page 125. 

 (See Plates XIX, XXIII, XXIV, XXV. XXVI, XXXVIII, XXXIX, XL, XLII, LIU.) 



Thtsanodictya iiermenia, sp. nov, 



Pago 133. 

 (See Plates XXXIX and XL.) 



Figure 7. The surface of an incomplete individual ; showing the very strong 

 primary bands and large quadrilles. No evidence is retained of 

 subordinate reticulation but the surface of the specimen has been 

 involved in shale and the structure obscured. The drawing is made 

 from a plaster-cast of a natural mould of the exterior. 

 Chemung group. Alfred, New Yorlc. 



Thtsanodictya apleta, sp. nov. 



Page 135. 

 (See Plate XXVI.) 



Figure 8. A fragment of the surface, sho^ving the coarse primary and 

 secondaiy quadrules. 

 Chemung group. Alfred, New York 



