PLATE IV. 



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, III. 



PAGE 



Fig. 1. ANTHASPIDELLA OBLIQUA, U. & E 265 



1 . Lateral view of an abraded specimen. Natural size. 



1 a. View of upper surface of same showing tho arrangement of the canals 

 and oscula. 



Fig. 2 ANTHASPIDELLA FLOBIPEBA, U. & E 9 



Median vertical section of the specimen figured on PI. I, showing the 

 vertii-al tubes of the central osculum, and ihe arrangement of the radial 

 canals aud the capillary tubuli. 



Fig. 3. ZITTELELLA LOBATA, U. & E 270 



8. View of upper surface of a small specimen. Natural size. 

 3 a. The lower surface of a larger specimen showing the lobate character of 

 the species. Natural size. 



3 ft and Sc. Small portions of transverse and vertical sections to show spi- 



cular structure, x25. 

 Fig. 4. STBEPTOSOLEN OBCONICUS U. & E 274 



4 and 4a. Two vi"ws of a specimen natural size, showing the irregular in- 



tertwining o! the canals. 



4 1). Median vertical section of the same specimen, showing the cloacal 

 tubes and the irregular canals. 



