DEVONIAN AND OLD RED PERIOD. 



141 



the enclosing rock in the boldest relief, exhibiting to the ob- 

 server the most minute details of their organisation. As before, 



Fig. %\.Zat>hrentjs corm'cula, of the 

 natural size. Devonian, America. (Ori- 

 ginal.) 



Fig. Ho. Cystipkyllum vesiculostttii, 

 showing a succession of cups produced by 

 budding from the original coral. Of the 

 natural size. Devonian, America and 

 Europe. (Original.) 



Fig. %v.Helio/>Jiylhim exigiiunt, view 

 ed from in front and behind. Of the natu- 

 ral size. Devonian, Canada. (Original.) 



the principal representatives of the Corals are still referable to 

 the groups of the Rugosa and Tabulata. Amongst the Rugose 

 group we find a vast number of simple " cup-corals," generally 

 known by the quarrymen as '' horns," from their shape. Of 

 il 



