^4 l)icrYosi»oNGibiE. 



seen in the figures of the species given on Plate I. They increase the 

 siiniiarity of these sponges to the living Euplectella, in which such openings 

 are the vacant or unobstructed portions of quadrules formed by the primary 

 pentactins and the rectangular intersection of the spicular bundles, rounded at 

 the angles by the encroachment of irregularly branching filigree work. 



The beautiful specimens of Cyatiiopiiycus which have been found in 

 great abundance in the Utica slate at Holland Patent, N. Y., have been the 

 means of affoi-ding a pretty clear conception of the structure of this sponge, 

 and the fine figures given by Rauff, supplemented by those here introduced 

 for comparison with the Dictyosponges, show the details of its composition. 

 Ui>on consulting figure 10, Plate I, which represents a large and finely 

 preserved example of this species, somewhat conventionally but judiciously 

 restored in parts, it will be observed that the mural openings may be crossed 

 by the larger cruciform spicules of the outer layer (which is not true of 

 Euplectella), but they are principally outlined by a pyritized film which 

 appears to be spicular, though not readily resolvable. These charactei's are 

 better shown in figure 12, which is an enlarged view of a portion of another 

 specimen. Cyathophycus* possesses a tuft of short root spicules, arid 

 Cyatliospongia Quehecensis, Dawson, has been i-epresented as having free 

 prostalia both about the aperture and over the outer surface of the Avall.f 



Plate I bears a number of figures representing another interesting 

 species from the Utica slate, occurring in association with Cyathopliycus 

 {Cyatlwdictyd) retieulatus, in which the mural openings are numerous and 

 very clearly defined, lying on the inner wall of the sponge and being sur- 

 rounded by a highly irregular network of cruciform spicules. The form and 

 structure of this sponge suggests little relation to C. reticniatus, but again 

 illustrates the occurrence of mural areoles which open through the inner Avail of 

 the sponge, but are crossed or obstructed by the stauractins of the outer Avail.;}: 



•This name Las been hitherto retained although, like Dictyophyton, it tends to perpetiinte the old 

 and erroneous conception of the algous nature of these fossils. Dawson pmposed to modify the term to 

 Cyathospongia, which would have been an appropriate substitute, had not the name already been in use 

 for a genus of thick-walled sponges. Cyathodictya would be in better harmony with the terminology 

 in this group. 



t After examination of specimens of this species from the Little Metis slates, it seems that the sim- 

 plicity of the reticulum and the absence of mural openings, ally it more closely with the species which 

 Sir William has referred to Protospongia, rather than to Cyathophycus (Cyathodictta) which 

 it resembles only in form. 



tMr. Walcott described from the Utica slate (Trans. Albany Institute, vol. x, p. 19, pi. 2, fig. 17, 

 1879) as Cyathophycus subsphwricus, a flattened, subcircular body, showing no structure, except 

 a small area in the center, which was regarded as aa aperture. Dr. Rauff {op. cit. p. 256, pi. 

 iv, flgs. 3, 4, 1894) has more recently studied these or similar bodies, anil figures them as shallow cups 

 with rather thick walls about the osculum. Only traces of the spicular structure were discerned. 

 Although the composition of these sponges is extremely obscure, Rauff h:is proposed for the species the 

 new genus Teganidm, and is disposed to laclade under the specific name Teganium suhsijhwricum the form 



