20 Report of the State Geologist. 



In several preliminary papers published in the Annual Reports 

 of the State Museum or of the State Geologist, beginning in 

 1863,* the writer has described a number of species from the 

 Devonian and Carboniferous rocks ; many of these descriptions, 

 however, being brief and incomplete, and without illustration. 



In this memoir all known species of this family from American 

 rocks are brought together ; the previously described species, 

 forty-six in number, are re-described, and a large number of new 

 forms are added, sufficient to make the total number of known 

 species of this single family something more than one hundred. 

 The work opens with a chapter on the general and spicular 

 structure of these organisms, their relation to other sponges, 

 their mode of growth, distribution and preservation. Following 

 this is an extended bibliography of these fossils and the detailed 

 descriptions of the genera and species, those of each principal 

 geologic formation being considered by themselv^es. 



The 108 species now known are divided among 27 genera, 16 

 of which are new. The paper is illustrated with many text 

 figures showing spicalar structure, and with 64 lithographic 

 plates. 



* 1863. Sixteenth Annual Report of the State Cabinet of Natural History. Ten species were 

 described and illustrated. 



1884. Thirty-fifth Annual Report on the State Museum of Natural History. A brief description of 

 *he genera Cyathophycus, Walcott, and Dictyophyton, Ectinodictya, Lyriodictya, Thamnodictya, 

 Phragmodictya, Cleiodictya and Physospongia, Hall, and Uphantaenia, Vanuxem, were given, 

 together with a revision of the species described in the Sixteenth Annual Report, and including 

 those described by Professors C. D. Walcott and R. P. Whitfield, T. A. Conrad and L. Vanuxem. 



1890. In the Ninth Annual Report of the State Geologist two new genera of this family, viz.: 

 Actinodictya and Cryptodictya, together with 10 newgpecies of this family of fossils, were described ; 

 thus making the entire number of species recognized up to that date, 46. 



