THE HEDERELLOIDEA — BASSLER 39 



of a set of loosely arranged, straggly tubes about 0.4 mm. in widths 

 branching at long intervals, 15 mm. or more, and giving rise to short 

 zooecia 1 mm. in length at angles of 30° to 45°, at distances averaging 

 2.5 mm. Tubes faintly annulated; zooecial apertures terminal, trans- 

 versely oval, opening upward and equaling the tubes in diameter. 

 Two zooecia in 5 mm. 



Occurrence. — Middle Devonian: Thedford (cotypes), Arkona, and 

 Bartletts Mills, Ontario (Widder shale); Pavilion and IK miles south 

 of East Bethany, N. Y. (Tichenor hmestone); 2K miles southwest of 

 Sylvania, Ohio (SiUca shale); Ann Arbor, Mich, (drift). 



(7o<2/pes.— U.S.N.M. Nos. 26574, 54117, 87969. 



HEDERELLA GERMANA, new specie 



Plate 4, Figure 6 



Although related to H. vagans, this species can be distinguished by 

 its wider, more coarsely annulated tubes, branching at considerable, 

 although shorter, intervals (12 mm.), usually at a right angle, and its 

 longer, more distantly spaced zooecia emerging at such a low angle 

 as often to remain in contact. Length of zooecial tubes 1.6 mm., 

 width 0.5 mm., with 1 to 2 zooecia in 5 mm. 



H. canadensis and H. crassilinea are also related species, which have 

 been distinguished under their respective descriptions. 



Occurrence. — Hamilton (Widder shale): Thedford, Ontario. 



Holotype.—U.S.lSl.M. No. 87934. 



HEDERELLA CONTORTILIS. new species 



Plate 8, Figures 5-8 



Nicholsonia canadensis Davis (not Hederella canadensis Nicholson), Kentucky 

 Foss. Corals, pt. 2, pi. 73, figs. 10, 11, pi. 78, fig. 16, 1885 (not pi. 57, fig. 6 = 

 Hernodia davisi; not pi. 80, fig. 15, undetermined). 



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

 fig. 16, 1887. 



Associated with H. adnata, and like it incrusting fenestellid Bryozoa, 

 is another species that differs in its distinctly narrower and shorter 

 zooecial tubes (0.4 mm. wide and 1.5 mm, long). It often grows in 

 such profusion as to form a contorted mat, but a colony unobscured 

 by other zoaria or its own branches shows that the zoarial growth is 

 rather regular, consisting of a main axis of a single tube from which 

 branches emerge at an angle of 50° or more at intervals of 3 mm., 

 these emitting zooecial tubes on alternate sides at an angle of 50°-60° 

 and at distances of about their own length with about 3 in 5 mm. 

 Frequently the zooecial tubes all arise on one side of the branch, thus 

 adding confusion among them. 



H. vagans has about the same width of tubes, but its zooecia are 

 shorter and branch at less frequent intervals. 



