132 DicnrospoNGiD^. 



quatlniles by spicular bands of the second order is visible here and thei-e over 

 the sui-face, and over the entire reticulum may be seen the extremely fine 

 ultimate di\-ision of the skeleton. At the base the margins of the diaphragm 

 are someAvhat irregularly thickened into nodes, but. the structure of the 

 reticulum over the basal surface is not retained although the form and outline 

 of this part are distinctly shown. 



The species is distinguished from T. rudis and T. Randalli by its greater 

 size and the coarseness of its primary meshes. 



The specimen we have used for the illustration of this species shows in a 

 very interesting manner how differently the reticulum may be retained on 

 parts of the same individual. Figures 3 and 4 (Plate xxxviii) represent 

 opposite sides of a specimen, on one the primary net-work only being apparent 

 while on the other the minute ultimate division of the net is i-etained. This 

 difference appears to be due to the fact that the specimen is a somewhat con- 

 cretionary mass of sandstone which was involved on one side in a film of fine 

 mud capable of retaining the impression of the most delicate spicular divisions. 



Dimensions. Length of an essentially entire specimen, 140 mm. ; width 

 above the middle and at the base 85 mm. 



Locality. From the Chemung group at Weston mills, Cattaraugus 

 county, and Wellsville, Allegany county. (Collection of E. B. PIall.) 



Thysanodictya scyphina, sp. nov. 



Plate xlii, Fig. 8. 



Sponge small, subcylindrical, the original specimens being somewhat con- 

 tracted at or near the aperture and having the prevailing mesh of the net-work 

 of small size, averaging 2 to 3 mm. on a side. The species is distinguished by 

 these characters from other members of the genus. 



The basal frill is clearly retained over a portion of the lower extremity 

 and shows a broadly crenulated or furrowed surface and an irregular margin. 



Dimensions. The length of the specimen, which has been somewhat com- 

 pressed vertically, is 36 mm., its basal diameter 30 mm. and the width of the 

 basal expansion 7 mm. 



Localitij. In the upper part of the Chemung group, Olean, Cattaraugus 

 county, N. Y. (Collection of E. B. PIall.) 



