REPORT OF THE DIRECTOR I916 183 



5 Single row of low nodes 



6 Triple row of low nodes, more or less fused vertically 



7 Large, simple nodes, obviously fused vertically 



8 Large, simple nodes 



9 Low, triple, grooved nodes 



10 Low, triple, grooved nodes 



11 Low, duplicate, grooved nodes 



The above details give a fairly adequate account of the char- 

 acters of the species. The length of the specimen is 180 mm, and 

 this length, if increased by the length of the smaller specimen, 

 with a slight allowance for the break, would be 220 mm. The 

 specific name is given as a recognition of Mr Armstrong's interest 

 and his diligence in the study of the paleontology of his neighbor- 

 hood. These specimens are from " about 8 miles east of Erie, Pa." 



ELUCIDATION OF THE GENUS CRYPTODICTYA 



(Plate 4) 



In the Monograph of the Dictyosponges its authors described as 

 Cryptodictya alleni, certain frond-shaped structures of 

 large size which seemed to have been sponge masses with extremely 

 thin, expanded reticulum and which, in being tossed together by 

 the waves, had assumed irregularly infolded shapes. There was no 

 evidence, from the study of these bodies, that the films had ever 

 been inclosed into vases or other symmetrical forms. The sponge 

 character of these organic structures was only presumptive, but 

 their association in the Chemung rocks of Cattaraugus county, 

 N. Y., was with other sponges and the occasional indications which 

 they presented, of structures which might be interpreted as spicular, 

 and also the fact that surfaces were irregularly marked by little 

 monticules or acute papillae, sometimes symmetrical but often 

 elongated and irregular elevated surfaces which might have served 

 as bases for spicular tufts and did indeed, when protruding into 

 the matrix, seem to be accompanied by evidences of such spicular 

 sponges. 



Mr Armstrong has recently discovered a series of small disks 

 which have the same general surface appearance as those of C . 

 alleni, but which are distinctly outlined, and I have little hesi- 

 tancy in comparing the latter with the type species of the genus. 

 These smaller disks are all of about the same size and average about 



