118 DiOTVOSPONOin J5. 



diniinislied in prominence, though the duplication of the latter is still more 

 pronounced than in Ceratodictya cincta. 



The reticulum is very fine-meshed throughout, with no evidence of any 

 especially predominating series of spicular bands. The prevailing mesh 

 measures about 1 mm. on each side and is subdivided by a single minor series. 

 There is no evidence of any ornamental projections from the surface in the 

 form of tufts or spicular ridges. 



Dimensions. This sponge is remarkable for the great length which it 

 attained. Plate xlii shows one excellently preserved sj)ecimen, incomplete, 

 however, at both ends, having a length, measured along its gently curving 

 axis, of 317 mm. In its entire length it bears thirteen double annulations, 

 the earliest of which, measured from the outer edges of the ridges, is 15 mm. 

 wide, and the last of them has about the same width. A second fragment 

 (Plate xliii, fig. 2) is nearly complete at the base and is straight for a distance 

 of 365 mm., the remainder being lost. The very long specimen shown on the 

 same plate (fig. 1) measures 500 mm. in length, with slight curvature, and 

 is complete at neither end. Fragments of the apertural end of full grown or 

 old specimens found in association with those referred to, have a much greater 

 width. One of these, doubtless of this species, is 130 mm. wide and to have 

 attained this width at the rate of increase shown in other specimens, the entii-e 

 sponge must have been not far from three feet in length. Allowance is, in 

 this estimate, made from the very evident fact that the sponge expanded much 

 more rapidly dui-ing the first one-third of its length than in later gro\vth. 



Localities. All the more extended specimens have been obtained in the 

 upper beds of the Chemung group, on Milo Cole's fann, near Ischua, Cattarau- 

 gus county. A single fragment of an old individual is from Randolph, N. Y. 

 Associated with it in the soft greenish shales at the former locality are speci- 

 mens of Lingida, Camarotcechia and Sfirifer. (Collection of E. B. Hall.) 



Ceratodictya cincta. Hall (sp.), 



Platk XXII, Pigs. 7-9. 



1884. Dietyophyton cinctnm. Hall. Thirty-fifth Ann. liept. N. Y. State 

 Mus. Nat, Hist., p. 472. 

 Sponge large, subcylindrical, showing slight evidence of tapering, and 

 though much compressed, evincing a nonnally circular cross-section. Surface 

 bearing closely-set, subequidistant, nan-ow and strong annulations separated by 

 furrows equal to them in Avidth. These form a purely ornamental configura- 

 tion of the surface and have no other relation to the reticulum. The reticular 



