12 Pratt, Bipolar Theory. 



nortli and south extra-tropical forms: — Selenka,DeGuerne, 

 r^ischcr, and Shipley, for the Gephyrea, Th^el for the 

 Holothurids, Ehlers for the Polycha:tes, I. C. Thompson 

 for the Plankton, and Pratt for certain littoral forms. 

 Giesbrecht has shown the bipolar Calarms Jiyperboreus to 

 be distinct from the species inhabiting warmer seas 

 {C. finmardiiais). Therefore, we cannot accept Ortmann's 

 statement that "(^r//thc results of investigations in special 

 " groups of animals tend to show that the theory held by 

 " Pfeffer and Murray, that both polar faunas are more 

 " closely related to each other than to any of the inter- 

 " mediate ones, is without support." 



This appears to bring to an end the published evidence 

 bearing upon the " bipolar " controversy. 



For the following account of the distribution of 

 Scalibregma inflahcvi I am indebted to Dr. J. H. Ashworth, 

 of Edinburgh. Further information on the subject will 

 be found in his memoir on the " Anatomy of Scalibregma 

 inflatiim" Quart. Joitrn. Micro. Science (in the press). 



Dr. Ashworth examined 40 specimens of Scalibregma 

 inflaUivi, 26 of which were from the United States 

 National Museum, the remainder from the museums of 

 Bergen and Stockholm. Those obtained from Scandinavia 

 were collected chiefly on the Atlantic coast of that 

 jjcninsula, the U.S. specimens along the east coast of the 

 American continent, the most southerly station at which 

 these were obtained being 40^ N. and the most northerly 

 44^ 23' N. 



Distribution. Scalibregma occurs eastward as far as 

 Cape Grebeni (the most southern point of Waigatsch 

 Island), western shores of Spitzbergen, Nova Zembla, 

 western coast of Norway, and western coast of Sweden (in 



