PLATE VIII. 



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. 



PAGE. 



Fig. 1. STBOTOSPONGIA MACULOSA U. & E 277 



1 and 1 a. Two views of the type specimen. Natural size. On the first the 



dark lines represent the sponge tissue, while in 1 a, the dark spots 



represent the mouths of canals. 

 1 b. The same specimen sawed vertically through the center to show the 



intertwining canals and sponge tissue. The latter is represented by 



dark lines. 

 1 c. Thin section, x9, showing relative thickness. 



1 d. Portion of 1 c, x!8, giving an obscure idea of the form and nature of 



the spicules. The spicular skeleton is clearly very much like that of 

 Dystavtospongia. 



Fig. 2. ANTHASPIDELLA MAGNIFICA U. & E 265 



2. Basal portion of specimen with the remainder drawn in outline. Natural 



size. 



2 a. Portion of the inner face of cup to show arrangement of canals and 



oscula. Natural size, 

 2 b. Portion of upper margin (outer side). 



2 c. Vertical section of same, showing canals, and thickness of sponge wall. 



Natural size. 



Fig. 3. DYSTACTOSPONGIA MINOB U & E 278 



3. A specimen of the natural size. 



3 a. Transverse section, x9. 



3 b. Vortical section, x9. Compare portions of this figure with 1 d. 



Fig. 4. DYSTACTOSPONGIA BUDIS U. E J79 



4. Portion of the surface of a specimen, natural size, showing the ikin inter- 



twining walls and rather large interspaces. 



4 a. Transverse section, n9. 



