PLATE I. 



The specimens figured on this plate are now in the Illinois State Museum. They 

 were collected by Dr. Oliver Everett from the Trenton limestone near Dixon, 111. 



PARE. 



Fig. 1. ANTHASPIDELLA MAMMULATA U. & E 258 



1. View of cup, showing the distributi in ol thu oscuh, their elevated mar- 

 gins, and the dense external laye , worn away at the margin. Natural 

 size. 

 1 a. Transverse section showing the thickness of the sponge and the vertical 



arrangement of the canals. Natural size. 

 1 b. Vertical section showing several canals and the direction of the spiculfi 



columns. 



1 c. Portion of 1 lj, x!8. 

 1 d. Central portion of 1 a, xlS, showing the arrangement of the spicules. 



Fig. 2. ANTHASPIDELLA FLOKIFERA U. & E. (See also PI. IV.) 25!> 



View of upper surface of a medium sized specimen, showing arrange- 

 ment of oscula and canals. Natural size. 



Fig. 3. ANTHASPIDELLA PABVISTELLATA U. & E lim 



Upper surface of the i ype specimen, natural size. The radial uiinals 

 have been worn or ground away so that the mouths of the radial 

 canals are exposed. 



