11(6 



DlCTYOSPONGlD^. 



PlIYSOSPONGIA MULTIBUR8ARIA, Sp. nOV. 

 PiATK ua. Fig. 7. 

 This is an aberrant form, referred to the genus Piiysospongia, pending a 

 more complete knowledge of its structure. The single specimen represents a 

 portion of one side of what must have been a very large sponge of whose 

 original proportions it is not possible to form an accurate conception. The 

 surface is flat and measures 175 ram. in length and 110 mm. in its greatest 

 diameter. This expansion is covered with a great number of small, rounded 

 elevations having tlie form of drooping pouches, the smaller of them resemb- 

 ling the nodes of Physospongi-a Dawsoni, but the longer appear to have been 

 of the penduh)us nature of the lobes in Botryodictya though of much smaller 

 size. These nodes ai-e arranged in vertical rows although there are portions 

 of the surface where the order is somewhat obscured by the overlapping of 



FiQURE 45. Spicules of Physospongia muUihuraarla, z400. Showing a largo Irregular pentact, fragments of ectiiuate 

 hezacU, smooth diact and a minute cleme. (J. M. C.) 



the longer nodes. At the bottom of the specimen, thirteen of these rows may 

 be counted, while toward the top, where the surface is broadest, there are as 

 many as twenty. No arrangement into transverse rows can be distinguished. 



A few of these processes show traces of reticulation about their basal 

 portions or over their summits, but where the interspaces are uncovered or 

 the nodes have been removed, the impression of a fine spicular net- work is 

 everywhere seen. The unbroken marginal portion at the right of the specimen 

 is without nodes, and here the reticulum is partially preserved in pyrite. 



The meshes and spicular bands appear to be in tv.'o not very clearly 

 marked seines, the principal bands^ so far as can be seen, being from 3 to 5 mm, 



