Spkciks of tiik Ciikmuno Group. 



119 



net-work is extremely fine and homogeneous, no large (juadrules being present. 

 The prevailing mesh is about 1 ram. square and is subdivided by a subsidiary 

 pair of spicular bands. These cover the entire surface both of the annulations 

 and furrows, without the intersection of any coarse bands. 



The entire dimensions of the cup are unknown. A large fragment with 

 a length of 120 mm. bears eight annulations, the height of each being about 

 5 mm. The diameter of this specimen is 120 mm. On one side of the cup the 

 growth of the annulations has been interrupted, evidently from accident, and 

 in the repair of thereticulum the regularity of the annulations ha? been greatly 

 disturbed. This species will be distinguished from the terminal e.xpanded 

 portions of O. Carpenteriana by more regularly equidistant annulations. 



Locality. In the sandstones of the Chemung group ; from a boulder at 

 Erie, Pennsylvania. Portions of several intlividuals occur in the same frag- 

 ment of rock and with them is the original specimen of Ceratodictya zonata. 

 (Collection of the Philadelphia Academy of Natural Sciences.) 



Ceratodictya zonata, sp. nov. 



Plate xu, Fiq. 8. 



1884. Dictyophyton cinctum, Hall {partim). Thirty-fifth Ann. Kept. N. Y. 

 State Mus. Nat. Hist., p. 473. 



Sponge small, slender, gradually expanding. Surface crossed by broad 

 and low annulations which are separated by narrower and shallow constrictions 

 toward the basal extremity which is wanting. These horizontal rings are not 

 sharply defined ; those over the median and distal parts of the cup are 

 flattened or somewhat depressed on their summit. There are eight annulations 

 in a length of 45 mm. 



Reticulum exceedingly fine, all of the quadrules being minute. The most 

 conspicuous of the spicular bands are represented by sharp horizontal lines at 

 the bottom of each constriction. 



Length of the only observed specimen 53 mm. ; diameter at the lower 

 end, 6 mm.; greatest diameter 14 mm. 



Locality. In the arenaceous beds of the Chemung group ; from a boulder 

 found at Erie, Pennsylvania. (Collection of the Philadelphia Academy of 

 Sciences.) 



