52 BULLETIN OF THE 



Mv. S. F. Baird presented a communication 



ON THE DECREASE OF FISH ON THE SOUTHERN COAST OP NEW ENGLAND, 



(This paper is published in Report of the U. S. Fish Commissioner for 

 1871-72.) 



Following the paper of Mr. Baird, Mr. Gill made some re- 

 marks on the relations of the fishes of Massachusetts to those of 

 other regions, affirming that the fauna of the State was composed 

 of two elements, a northern and southern, the boundaries of 

 which were, on the whole, tolerably well defined by Cape Cod. 

 The forms found north of the Cape were in great part represented 

 by corresponding or identical species in northern Europe, while 

 those inhabiting the southern waters were mostly nearly allied to 

 forms characteristic of the Caribbean Sea, or merely wanderers 

 from that region. In respect to the influence of the blue fish on 

 the supply of scup, he was inclined to believe that while the 

 pounds are in operation, the diminution of the scup would be 

 accelerated in constantly increasing ratio up to a certain point, 

 the disturbance of the equilibrium being due to the difference of 

 habits of the two species. The scup is rather a shore fish, while 

 the blue fish is an open water species and exempt in greater pro- 

 portion from capture in pounds ; therefore, the ratio of prey to 

 the enemy would be constantly diminished by the capture of a 

 disproportionate number of the former. 



24th Mebtinq. April 6, 1872, 



The President in the Chair. 

 Mr. C. E. DuTTON read a paper 



ON THE measurement OF THE PRESSURE DEVELOPED BY THE EXPLO- 

 SION OF GUNPOWDER IN FIREARMS. 



Mr. S. Newcomb made a communication 



ON THE POSSIBILITY OF A UNIVERSAL ATMOSPHERE. 



Mr. B. F. Craig exhibited a recently invented apparatus for 

 the generation of ozone from the flame of the Bunsen burner. 



