PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



issued iMiv\jA, vJ^l ^y '^* 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 

 Vol. 87 Washington: 1939 No. 3068 



THE HEDERELLOIDEA, A SUBORDER OF PALEOZOIC 

 CYCLOSTOMATOUS BRYOZOA 



By Ray S. Bassler 



The middle and upper Paleozoic strata of North America contain 

 many incrusting, tubular, corallike organisms usually classified as 

 aberrant cyclostomatous Bryozoa. Hederella, Reptaria, and Hernodia 

 are the best-known genera, each represented by a few previously 

 described species some of which have been identified from such widely 

 separated horizons and locaHties that their names have little strati- 

 graphic significance. The care of large collections of these fossils 

 accumulated in the United States National Museum during the past 

 30 years led me to take up their study and, in 1934,^ to propose the 

 name Hederelloidea as a new order of the Cyclostomata, since the 

 typical bryozoan ancestrula was observed in a number of the species. 

 With the present-day recognition of the Cyclostomata as an order, the 

 Hederelloidea becomes subordinal in rank. At present all the six 

 known genera are classified under a single family — Reptariidae 

 Simpson, 1897. 



The earliest known forms of cyclostomatous Bryozoa occur in the 

 lowest Ordovician (Buftalo River series) of Arkansas, where several 

 species of Crepipora LHrich, 1882, of the suborder Ceramoporoidea 

 occur. This suborder expands rapidly, particularly in the Devonian 

 and Mississippian periods, with the very abundant development of 

 Fistalipora and its alfies, but so far as known becomes extinct with 

 the close of the Paleozoic. In the Chazyan, following the Buffalo 



» Proc. Qeol. Soc. America for 1933, p. 346, 1934. 



139917—39 1 25 



