1898-1902. No. a] BRYOZOA. 43 



is only one report of its occurrence in the east arctic region (Ice Fjord 

 on Spitsbergen, according to Smitt). The reason that the species is not 

 found in the numerous sounds and currents of East Spitsbergen, can scarcely 

 be that they cannot thrive there. And if, in reality, it is not more widely dis- 

 tributed in the east arctic region than our present acquaintance with this 

 matter indicates, the reason must be sought in the fact that the species 

 has not yet had time enough for a circnmpolar distribution. 



There is another thing that may possibly be deduced from the 

 distribution of this species. As it occurs in abundance off Greenland 

 and in the North American archipelago, but very sparsely off Spitsbergen, 

 it is highly probable that Greenland lies nearer to the distribution-centre 

 than Spitsbergen, whither it must have come from the west. A simi- 

 lar chain of reasoning may be applied to Flustra serrulata. In the 

 east arctic region, this species has only been found in the Kara Sea 

 (Levinsen), and it is natural to suppose that it has come thither from 

 Greenland. 



The species described as new cannot in the mean time be employed 

 in zoo-geographical considerations, and with regard to the others, the 

 greater number of them are circumpolar, while again others such as 

 Schizoporella produda, Packard, and Porella saccata, var. rostrata, 

 HiNHKS, are up to the present found only in west arctic waters. 



There thus appears to be a difference between the west and east 

 arctic waters as regards the Bryozoan fauna, and one would think that 

 a careful study of the distribution of the different species, would lead to 

 important conclusions regarding the locality in which the arctic condi- 

 tions first took the place of the Tertiary. The above seems to point to 

 the probability that the first creation of the arctic forms took place 

 north of America, and not north of Europe. On the whole, it is pos- 

 sible that the great changes in the natural conditions of the earth are 

 the most important, or one of the most important, of the species-form- 

 reasons. 



HiNCKS described a Cellaria from Queen Charlotte Islands, C. man- 

 dibulata, which, on account of its occurrence might possibly be sup- 

 posed to be arctic. This is not the case, however, for A. Robertson i 

 now states that the above-named species has a large distribution, and 

 is most general in southern waters. C. articulata is thus left as the 

 sole representative of its genus in the arctic fauna. On the other hand, 



• Non-incrusting chilostomatous Bryozoa of the West Coast of N. America. Un 

 veristy of California Publications. Zoology. Vol 12, no. 5, p. 289. 



