BRYOZOA OF THE PACIFIC COAST 

 OF AMERICA 



Part 3, Cyclostomata, Ctenostomata, 

 Entoprocta, and Addenda 



By Raymond C. Osburn, Ph.D., D.Sc. 



Plates 65 - 82 



A report based chiefly on the Bryozoa collected by the Allan Hancock 

 Expeditions, 1932-1941, in the Velero III (see pages 1-2 of Part I) and 

 in the Velero IV in 1949-1952. 



Additional material received from several sources has greatly enlarged 

 the scope of this study. Especially should be mentioned contributions 

 from the U. S. National Museum, the collections of the Alaska Crab 

 Investigations from southern Alaska, and those from the Point Barrow, 

 Alaska, Arctic Research Laboratory. Also practically every museum and 

 marine laboratory on the Pacific coast of the United States and Canada 

 has contributed some specimens of interest in this extensive survey. 



Order GyGLOSTOMATA Busk, 1852 



Busk in 1852 proposed the name Cyclostomata for this group of 

 Bryozoa, since which time until rather recently it has generally been 

 considered a suborder of the order Ectoprocta. In 1926 Borg pointed 

 out striking anatomical differences between the Cyclostomata and the 

 Cheilostomata-Ctenostomata and gave the former ordinal status under 

 the name Stenolaemata. At the same time Borg (1926:490) included in 

 the Stenolaemata the old fossil order Trepostomata of Ulrich, but did 

 "not wish to give any decided opinion on this point." Later (1944:18-19) 

 Borg definitely made the Trepostomata a suborder of the Stenolaemata, 

 parallel with the Cyclostomata, and included in it the Horneras, Het- 

 eropores, Lichenopores and their allies. 



While it is now generally recognized that the cyclostomes are suf- 

 ficiently different from other bryozoans to warrant their separation in 

 a distinct order, the merging of the Trepostomata with this order and 

 the inclusion of the Horneras, Heteropores and Lichenopores in the 

 Trepostomata has not been accepted. The Trepostomes are all Palaeozoic 

 and do not occur above the level of the Permian. 



[613] 



