38 PROCEEDINGS OF THE NATIONAL MUSEUM vol.87 



HEDERELLA DELICATULA. new species 



Plate 11, Figures 1-8 



Hederella canadensis (part) Hall and Simpson, Pal. New York, vol. 6, pi. 65, 

 figs. 5, 7, 1887. 



This very delicate but abundant species may be recognized easily 

 by its threadlike zoarium, which, upon sufficient magnification, 

 resolves itself into a main axis giving rise, often at right angles and 

 intervals of about 1.5 to 6 mm., to equally narrow branches from 

 which, as well as from the main axis, the short zooecia arise on alter- 

 nate sides at angles of about 45°. All the other characters are as in 

 the larger typical species of the genus. Frequent overgrowth of the 

 branches results in a dense mat in which it is hard to trace the arrange- 

 ment of the tubes. Zooecial tubes are 0.8 mm. in length and 0.15 

 mm. in width; 4 to 5 zooecia in 5 mm. 



This, the most delicate member of the genus, is in marked contrast 

 with such forms as H. rohusta and H. reimanni, yet the zooecial 

 characters of the three are essentially the same except for size. 



Occurrence. — Middle Devonian: 18-Mile Creek, etc., Erie County 

 (cotype) (Wanakah shale), 3 miles west of East Bethany, and York 

 (Centerfield shale), Iji miles south of East Bethany (cotype) and 

 Pavilion (Tichenor Hmestone), Moscow, Leicester and Kashong Creek 

 (Moscow shale), all in New York; Thedford (cotype) and Arkona, 

 Ontario (Widder shale); 2}^ miles southwest of Sylvania, Ohio (Silica 

 shale); Lebanon, Ky. (cotype) (Sellersburg limestone); Milwaukee, 

 Wis. (cotype) (Milwaukee limestone); Falls of the Ohio (Upper Jef- 

 ferson ville limestone) (cotype); Petoskey Cement Co., Petoskey 

 (Gravel Point limestone), Phelps Quarry (Upper Alpena limestone), 

 and Rockport quarry, Alpena County (Upper Ferron Point formation), 

 ji mile southeast of 4-Mile Dam, Alpena County (Norway Point 

 formation). Partridge Point, 3 miles south of Alpena (Partridge Point 

 formation), 1}^ miles northeast of Bay View and 1.6 miles north of 

 Norwood, Charlevoix County (Petoskey formation), ji mile north- 

 west of Bolton, Alpena County, and Thunder Bay quarry, Alpena 

 (Alpena hmestone. Dock Street clay), all in Traverse group of Michigan. 



Coiypes.— U.S.NM. Nos. 26574, 50247, 54082, 54100, 54120, 

 57529, 87898, 87899, 87900-87906. 



Hederella vagans section 



HEDERELLA VAGANS. new species 



Plate 4, Figures 1, 2 



Hederella canadensis Hall and Simpson (part), Pal. New York, vol. 6, pi. 65, fig. 

 14, 1887 (not Nicholson, 1874). 



Zoarium usually incrusting the epithecated sides of Favosites but 

 also growing upon Heliophyllum and other cup corals and consisting 



