30 OSBURN 



Osburn- (1923) studied the Bryozoa collected by the Southern 

 Party of the Canadian Arctic Expedition and gave records of 47 species 

 which extended their range westward from Greenland. But only 18 

 of these were from as far west as Alaska and all of them were already 

 known from the Atlantic-Arctic region. This fact led him to state his 

 belief that "when our records of arctic Bryozoa are more complete for 

 the entire area around the North Pole, we will find that practically all 

 of the true arctic species are circumpolar in distribution." 



Borg^ (1933) attempted an analysis of the arctic and boreal species 

 and listed 93 species which he considered to be purely arctic ("rein 

 arktisch"), of which only 32 were supposed to be circumpolar. But Borg, 

 like Nordgaard, was limited by lack of information on the Pacific- 

 Arctic area. 



Recently, through the courtesy of the Hancock Research Foundation 

 of the University of Southern California, Osburn* has had the oppor- 

 tunity to study a collection of 113 bryozoan species made by Professor 

 and Mrs. G. E. MacGinitie at the Arctic Research Laboratory, Point 

 Barrow, the most northwestern part of arctic Alaska. Some of these 

 same species have also been taken at Nunivak Island and the Pribilof 

 Islands in the eastern part of the Bering Sea, but well north from the 

 Aleutian peninsula. 



The analysis of this interesting series shows that of the 113 species 

 from Point Barrow all but 11 were already known from the more 

 eastern area, Greenland to the Kara Sea, all occurring under strictly 

 arctic conditions. This leads us definitely to two conclusions: 1, that 

 there is no significant difference between the bryozoan faunas of the 

 Pacific-Arctic and Atlantic-Arctic areas, and, 2, that there is a pre- 

 ponderance of circumpolar species in the Arctic Ocean, w^hether or not 

 they are all "rein arktisch." 



As we have no definite knowledge of the place where any of these 

 species originated, it appears futile to discuss whether certain ones arose 

 in the polar zone and extended their range southward, or if the reverse 



2Rept. Canadian Arctic Exped. 1913-18. Vol. 8, part D; Bryozoa. Ottawa. 

 13 pp. 



^Uber die geographische Verbreitung der innerhalb des arkitschen Gebietes 



gefundenen marinen Bryozoen. Arch, fiir Naturgeschichte, n.f., Bd. 2, Heft 1, 

 pp. 136-143. 



*Bryozoa of the Pacific Coast of America. Allan Hancock Pacific Expeditions, 

 Vol. 14, Pts. 1, 2, 3, 1950-52-53. 



