Plate 10 



Page 



1,1'. Hederella michiganensts, new species (see also pi. 12, fig. 5) 54 



1, Portion of one of the types consisting of large irregularly branch- 

 ing zooecia. 

 Middle Devonian (Traverse-Upper Gravel Point limestone), 



Emmet County, Mich. 

 1, Portion of an example incrusting a Heliophyllum, illustrating 



more regular branching. 

 Traverse (Ferron Point formation), Rockport quarry, Alpena 

 County, Mich. 



2. Hederella robiista, new species (see also pi. 12, figs. 6, 7) 54 



The holotype showing the large tubes branching regularly into 



well-defined groups. 

 Middle Devonian (Traverse-Norway Point formation), Norway 



Point Dam, Alpena County, Mich. 



3. Hederella clarket, new species 50 



The holotype, well characterized by its zoarium of medium-sized 

 tubes branching at regular intervals into broad clusters of 

 zooecia. 



Hamilton (Ludlowville-Centerfield shale), 3 miles west of East 

 Bethany, N. Y. 



4. Hederella obesa, new species 53 



Portion of the type, a large specimen incrusting the base of a 

 Fistiilipora. The large, very short, broad zooecia arising on 

 alternate sides of a central tube form the specific characters. 



Hamilton (Ludlowville-Tichenor limestone), 18-Mile Creek, N. Y. 

 5, 6. Hederella magniventra, new species 52 



The type specimen, X 2 and X 4, incrusting a brachiopod and 

 illustrating the short, large, swollen zooecia and the rather 

 frequently dividing branches. The example of H. delicatula 

 in the lower right corner illustrates the great variation in 

 size in species of Hederella. 



Middle Devonian (Traverse-Lower Gravel Point limestone), 

 Petoskey, Mich 



85 



