56 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.87 



Zoaria incrusting cup corals and other organisms where they form 

 colonies as much as 7 cm. in length and branching at intervals of 

 8 mm. at angles of about 45°. Each branch appears to be made of 

 three parallel rows of elongate tubes, which in reaUty consist of a 

 central one giving rise on alternate sides to zooecia about 2 mm. long 

 and 0.35 mm. wide at such a low angle as to remain in contact. 

 Surface of tubes transversely rugose; apertures transversely oval and 

 equaling the tubes in width; 2K to 3 zooecia in 5 mm. measured 

 along the same side of a straight branch. 



Occurrence.— llamilton group: Moscow (cotype) (Moscow shale- 

 Windom member), 3 miles west of East Bethany (Centerfield shale), 

 and IK miles south of East Bethany (cotype) (Tichenor limestone), 

 IK miles southeast of East Bethany (Kashong shale), all in New 

 York; Thedford, Ontario (Widder shale) (cotype). 



Cotypes— V.S.N. M. Nos. 87947-87949. 



HEDERELLA COMPACT A. new species 



Plate 5, Figure 13 



Allied to H. parallela is a species from the Middle Devonian of 

 Michigan, with a similar growth habit but differing in that the zooecia 

 are conspicuously shorter and broader (1.5 mm. long by 0.7 mm. wide), 

 with 4 to 4)^ in 5 mm., and budding at an equally acute angle. The 

 initial tube from which they arise is so narrow that the zooecia appear 

 as a parallel, compactly and alternately arranged series of rectangular 

 tubes on each side of the middle line. Branching of the zoarium 

 occurs at an angle of 20° and more frequently than in other members 

 of the group. 



Occurrence. — Middle Devonian (Traverse-Partridge Point forma- 

 tion): Partridge Point, 3 miles south of Alpena, Mich. 



Holotype.— v. S.'N.M. No. 54114. 



HEDERELLA BIUNEATA, new species 



Plate 5, Figures 9-11 



The specific name of this minute species of the H. parallela group is 

 suggested by the characteristic bilineate arrangement of the two rows 

 of small, short, broad rectangular zooecia. The zoarium branches 

 rather regularly at intervals of 3 mm. in the vicinity of the ancestrula, 

 but elsewhere it may form delicate lines of zooecia 9 mm. or more in 

 length before division occurs, in this case at an angle of 60°-90°. The 

 zooecia average 1.0 mm. in length and about 0.3 mm. in width, with 

 5 to 6 m 5 mm. ; they bud from the main axis at such a low angle that 

 they remain confluent ^\dth each other, and are decorated with delicate 

 transverse wrinkles. Apertures transversely oval, rising at an angle 

 from the zooecial tubes. 



