Plate 2 



Page 

 1-2' . Hederella parallela, new species 55 



1, Portion of a zoarium incrusting a cup coral (Heliophyllum) 



showing the main axis and several branches composed of 

 zooecial tubes almost parallel to one another. 

 Hamilton (Ludlowville-Tichenor limestone), IJi miles south of 

 East Bethany, N. Y. 



2. Portion of a main branch incrusting a terebratuloid shell. 

 Hamilton (Widder shale), Thedford, Ontario. 



2', Another example incrusting a coral in which the main axes of 



two colonies cross each other. 

 Hamilton (Moscow shale), Moscow, N. Y. 



3. Hederella triseriata, new species 58 



The type zoarium incrusting a Stropheodonta, showing a portion 

 with parallel branches with zooecia in contact and broader 

 than in the related H. parallela. 

 Devonian (Snyder Creek shale), Fulton, Mo. 

 4, 5. Hederella persimilis, new species 49 



4, An example in which overlapping of the branches has produced 



a complex zoarium. 

 Middle Devonian (Traverse-Gravel Point limestone), Bay View, 

 Mich. 



5, Young zoarium illustrating method of branching and budding. 

 Middle Devonian (Traverse-Lower Gravel Point limestone), 



Petoskey Cement Co., Petoskey, Mich. 



6. Hederella halyson (Fenton and Fenton, 1924) (see also pi. 5, figs. 4, 5, 



and pi. 12, fig. 1) 48 



Base of a zoarium with ancestrular portion much obscured but 



with radiating branches showing the typical structure, 

 Devonian (Cedar Valley formation), Buffalo, Iowa. 



7. Hederella rugosa, new species (see also pi. 3, figs. 7, 8) 49 



A well-developed example incrusting Heliophyllum. 

 Hamilton (Widder shale), Thedford, Ontario. 



77 



