PLATE VL 



TiLT'iwiVM Peaciiii, Nich. and Eth., jiin , vur. Canadense. (Pago 24.) 



Figure], Fragment of a largo specimen. Natural size. 



'^ 1 a. A smaller specimen. Natural s'zo. 



'•' 1 b. Polished section of a small specimen, showing concentric lines. 

 Natural size. 



" 1 c. Transverse section, enlarged about forty times. 

 " 1 (I. Part of the same enlarged about ninety times. 



" 1 e. Transverse section showing one of the water canals, (?) Enlarge. I 

 about forty times. 



'' If. Longitudinal section, showing the wavy walls of the corallites, and 

 the concentric lines, crossing these nearly at right angles. 



