Ball.] 164 [November 10, 



Mr. W. H. Dall made a few remarks upon the distribution 

 of marine animals, asserting that their range was influenced 

 more by the temperature of the water than by the dej>th or 

 other conditions. 



He showed that the floating ice line of Bering Sea (which passes 

 between the PribylofF and St. Matthew groups of islands, touching 

 the continent near Kuskoquim Bay), governed the distribution of the 

 fish and mollusks of those waters. It is the northern limit of all the 

 more southern forms, some of which range as far south as Monterey. 

 It is the southern limit of almost all the truly arctic species. The 

 fur seal is never found to the north of it, though often erroneously 

 spoken of as coming from Bering Strait; the polar bear never passes 

 to the south of this line; the cod invariably keep to the south, and 

 the mullet to the north of it. It is also the limit of distribution of 

 many fuci and seaside plants. 



Where the water is cooled by northern currents, or by glaciers, 

 deep water species of mollusks, especially brachiopods, are found at, 

 or even above low water mark. Where the surface water is warm, 

 these mollusks, which in the north are found near the shore, are only 

 obtained at a depth of many fathoms. 



The President gave notice that the first series of lectures 

 for the season, entitled Sketches of Animal Life, would be 

 given by Mr. Edward S. Morse upon successive Monday 

 evenings, commencing November 8th. 



Section of Microscopy. November 10, 1869. 

 Mr. R. C. Greenleaf in the chair. Sixteen persons present. 



Dr. IT. TIagen called the attention of the Section to the 

 statements of Professor Listing of Gottingen, who had re- 

 cently 1 given some suggestions concerning the further im- 

 provement of the microscope. 



1 itfachr. d. kgl. Gesell. der Wissenseb., 1869, No. I, and PoggendorfTs Annaleu, 

 1869, T. xvi, p. 467. 



