386 



Report of the State Geologist. 



Figure 43. Spicules of Physospongia Colletti ; frag 

 ments of denies, anchorate clavules and echinate hex 

 actins, etc. x65. (J. M. C.) 



shown in figs. 5 and 6 of the plate cited. The aperture of the cup appears 

 to be smooth and its margin regular and even, without processes or spicular 

 projections. 



Skeleton. As in Physospongia Dawsoni, the vertical bundles in this 

 species are composed of a great number of smooth rods, there being associated 



with them anchors and denies. In the 

 material under examination the spicular 

 structure is not very satisfactorily retained, 

 but it would seem as if these anchorate 

 and clemate rods were comparatively less 

 abundant than in P. Dawson i, and tliey 

 prove to be of somewhat smaller size. The 

 predominant pentactins are of large size and 

 strongly echinate. It is presumed that 

 these lay at the angles of the quadrules and their abundance is in contrast to 



the comparatively rare 

 occurrence and small 

 size of similar bodies 

 in P. Daivsoni. The 

 surface of the nodes 

 and depressions is 

 very minutely and 

 ret-angularly reticu- 

 lated but so little of 

 the spicular frame- 

 work over those areas 

 lias been preserved 

 that only the large 

 umbel (fig. 44) can 

 be referred thereto. 

 It has been observed 

 that although the 

 specimens of P. Daw- 

 sunt have afforded 

 much more satisfac- 

 tory means of study- 

 kioi-rk 44. spicules of physorpongia coiu tn. xioo. (j. m. o ing the spicular ele- 



ments of the skeleton, no umbels have been found in that species. Presum- 

 ably in P. Colletti spicular tufts were present at the intersection of the 



