THE CIRCUMPOLAR DISTRIBUTION OF 

 ARCTIC- ALASKAN BRYOZOA 



By 



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



The similarity of the bryozoan fauna of the Greenland area with 

 that of northern Europe has suggested to several students of this group 

 that many of the arctic species may be circumpolar in distribution. How- 

 ever, until recently we have had only very incomplete data except for 

 the region extending from Greenland to Nova Zembla and the Kara 

 Sea, or approximately from 75° West Longitude to 75° E. L., consider- 

 ably less than one half the way around the borders of the Arctic Ocean. 

 The much greater extent, 210°, from the Greenland region westward 

 to the Kara Sea, was almost unknown as far as the Bryozoa are concerned, 

 with just a few references to some of the species, and the arctic area 

 north of the Pacific Ocean was practically untouched. This lack of 

 information led Nordgaard^ (1918) to state: "I am of opinion that 

 the arctic fauna is not a homogeneous one around the pole. We may 

 divide in two principal groups, viz.: 1. The arctic fauna of the Atlantic 

 region. 2. The arctic fauna of the Pacific region." Nordgaard's error 

 is due to the fact that he had no data on the true arctic fauna of the 

 Pacific region, but accepted the "Alaska" records from Hincks and 

 Robertson which were from southern Alaska, south of the Aleutian 

 peninsula and therefore in the Boreal Zone. 



iBryozoa from the Arctic Regions. Troms0 Museums Aarshefter 40, Nr. 1, 

 p. 95. 



29 



