PLATE V. 



SPATioroaA AREOLATA. (page 21 ) 



Figure 1. Fragment of the upper surface of the zoarium, showing monticules, 



and one of the projecting processes at the margin. Natural 

 size. 



'^ 1 a. Fragment of the under surface showing the hexagonal concave 

 areas. Natural size. 



^' 1 b. Another fragment of the under surface showing three of the pro- 

 jecting processes. Natural size. 



'^ 1 c. Tangential section 'showing a few spiniform tubuli. Enlarged 

 about thirty times. 



" 1 d. Tangential section of a single cell, enlarged about ninety times. 



" 1 e. Portion of a transverse section cut as far below the surface as the 

 extreme tenuity of the zoarium would admit; showing spini- 

 form tubuli. Enlarged about thirty times. 



" 1 /. Part of a longitudinal section, showing the larger tubes with very 

 few diaphragms, and two or three of the interstitial tubes in 

 which the diaphragms are more numerous. Enlarged about 

 thirty times. 



'' 1 g. Longitudinal section showing the under surface with one of the 



concave areas, and the upper surface buried in the matrix. 



Enlarged about fifteen times. 

 " 1 7i. Longitudinal section showing upper surface of the zoarium, the 



lower surface being embedded in the matrix. Enlarged about 



fifteen times. 



" 1 ?. Transverse section (the uj^per figure) and longitudinal section (the 

 lower figure) of one of the projecting processes. Enlarged 

 about tliirty times. 



