356 



Report of the State Geologist. 



(?) ECTENODICTYA, Hall. 



1884. Ectenodictya, Hall (partim). Thirty-fifth Ann. Kept. N. Y. State Mus. 

 Nat, Hist., p. 466. 



The name Ectenodictya was introduced for certain forms of apparently 

 more or less irregular growth, which seemed to have expanding or unenclosed 

 fronds. Both in the upper Devonian and the lower Carboniferous faunas 

 sponges of such aspect have been found, with a surface usually free of nodes 

 or other ornamental characters. The absence of a well defined form in these 

 species was the principal reason for placing them together under a single generic 

 term, although the division could, by the very nature of its composition, have 

 little more than a temporary value. In 1884, two species, E. implexa and E. 

 expansa were described from the AVaverly sandstone, E. BurUngtonensis from 

 the Burlington group and E. eccentrica from the Keokuk group. Fossils of 

 like character are also abundantly known in the Chemung group but no 

 names have been applied to them. The accession of material has shown that 

 such Chemung specimens indicate, by one or another set of characters, relations 

 to some of the larger sponges of the group, many of these imperfect fronds 

 probably representing the. species Prismodictya choanea, D. Ahnondensis, 

 or some similar sponge in which the expanse of surface is large and the pris- 

 matic aspect obscured. Thus, also, with most of the described species of 

 Ectenodictya; E. Burlingtoriensis seems a probable representative of the 

 genus Lyrodictya ; E. expansa undoubtedly represents a species of Tiiysano- 

 dictya and E. eccentrica*, as now known, is the basal diaphragm of a 

 sponge like Phragmodictya, but having a structure necessitating its 

 removal to another and new genus, Aclceodictya. There remains, then, but 

 the type-species of Ectenodictya, E. implexa, whose apparent structure is 

 here described. 



Ectenodictya implexa, Hall. 



Plate liv, Figs, 3, 4. 



1884. Ectenodictya implexa, Hall. Thirty-fifth Ann. Kept. N. Y. State Mus. 

 Nat. Hist., p. 475, pi. (18) 10, fig. 1. 



"Frond a reticulate expansion, assuming a variety of form from pressure or 

 other causes; the original form has been apparently broadly funnel-shaped or 

 ovoid. Base unknown. 



•Th»B8 specios were first desortbed as Phr aomodictta. 



