PLATE V. 



Fig. 1. HELIOPHYLLUM CANADENSE, Billings. Nat. size. (p. 25.) 



Fig. 2. HELIOPHYLLUM CAYUGAENSE, Billings. The calice viewed from above. Nat. 

 size. (p. 26.) 



Fig. 3. HELIOPHYLLUM COLLIGATUM, Billings. Upper surface of a fragment. Nat. 



size. (p. 28.) 



3a. Side-view of the same, showing the periodic expansions of the corallites. Nat. 

 size. 



Fig. 4. HELIOPHYLLUM COLBORNENSE, Nich. Nat. size (p. 25.) 

 Fig. 5. DIPHYPHYLLUM GRACiLE, McCoy. Nat. size. (p. 33.) 

 Fig. 6. DIPHYPHYLLUM STRAMINEUM, Billings. Nat size. (p. 33.) 



