DEVONIAN AND OLD RED PERIOD. I4!I 
the enclosing rock in the boldest relief, exhibiting to the ob- 
server the most minute details of their organisation. As before, 
Fig. 81.—Zaphrentis cornicula, of the 
natural size. Devonian, America. (Ori- 
ginal.) 
Fig. 80.— Cystiphyllum vesiculosum, 
showing a succession of cups produced by 
budding from the original coral. Of the Fig. 82.—Heliophyllum exiguum, view- 
natural size. Devonian, America and ed from in front and behind. Of the natu- 
Europe. (Original.) ral size. Devonian, Canada. (Original.) 
the principal representatives of the Corals are still referable to 
the groups of the Rugosa and Zabulata. Amongst the Rugose 
group we find a vast number of simple “‘ cup-corals,” generally 
known by the quarrymen as “horns,” from their shape. Of 
