G. GENERAL NATURAL HISTORY AND ZOOLOGY. 261 



catching salmon, to learn that the last report of the Commis- 

 sioner of Fish and Fisheries for New Brunswick and Nova 

 Scotia announces a very decided increase in the number of 

 salmon, in consequence of the protective measures that have 

 been established by the Dominion government. He recom- 

 mends, what will also be agreeable news to our fishermen, 

 that the salmon rivers be freely leased to gentlemen, under 

 proper regulations, as the best method of preventing illegal 

 poaching, and the improper destruction of breeding and im- 

 mature fish. Among the chief measures to which the increase 

 in question is due is ascribed the introduction of ladders into 

 the dams on the streams, both salmon and alewives, by their 

 means, passing up waters from which they had for a long time 

 been absent. Report of Canada Department of 3Iarine and 

 Fisheries, 1869, 1870. 



USE OF THE PECTORAL FINS OF FISH. 



Mr. Hansen, in discussing the movements of the fins of fish- 

 es in water, remarks that the propelling power of the pecto- 

 ral fin is directed upward and forward, and is intended to as- 

 sist the passage of the water into and out of the gills, and 

 thus aid in respiration. When only one pectoral fin is moved, 

 the body rotates around its longitudinal axis ; a more decided 

 movement of both fins will raise the anterior extremity of 

 the body in the water. When flying-fish ascend quickly to 

 the surface by means of the active movement of the pectoral 

 fins, they describe an arc over the water, but ultimately fall 

 back into it. For this reason they are scarcely to be included 

 among flying animals. 1 C, 1870, xlv., 720. 



RELATIONS OF GANOIDS TO PLAGIOSTOMES. 



Dr. Albert Gunther, of the British Museum, has presented 

 an elaborate communication in Nature upon the relationships 

 of the remarkable animal discovered not long since in Queens- 

 land, known as the Ceratodus forsteri (or Dawson salmon), 

 which is, in general characters, an amphibian-like fish, allied 

 to Lepidosiren, etc. Considering Ceratodus as a form of ga- 

 noid fishes, Dr. Gunther has been induced, as the result of his 

 investigations, to unite the Plagiostomata (sharks and rays) 

 with the ganoids, since they agree in having a third con- 

 tractile chamber in addition to the ordinary two divisions of 



