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Monday, l^th December 1854. 

 Right Rev. Bishop TERROT, V.P., in the Chair. 

 The following Communications were read : — 



1. Some Observations on the Salmonidae. By John Davy. 

 M.D., F.R.S., Lond. and Edin., Inspector-General of 

 Army Hospitals. 



These observations are given in seven sections :— 

 In the 1st, the author treats of the air-bladder of these fish, and 

 the contained air, which he found, in every instance that he exa- 

 mined it, to be chiefly azote. 



In the 2d, he points out a mistake he had fallen into in the m- 

 stance of the female fish, as regards its abdominal aperture, which, 

 in a former paper he had described as open only for the passage of 

 the ova ; on further examination made on the larger species, he has 

 ascertained, that though virtually closed, except during the spawning 

 time, it is not absolutely, either by a membrane or adhesion. 



In the 3d, on the breeding localities of the Salmonidae, he states 

 his opinion, that running water is not essential to the hatching of 

 the ova, and he adduces instances in proof and illustration. 



In the 4th, which is on the variable time of the hatching of the 

 ova, he describes examples of difference as to time of the production 

 of the young fish under circumstances apparently identical, or cir- 

 cumstances only very slightly different, tending to show the influence 

 of a vis insita in the several ova. 



In the 5th, on circumstances and agencies likely to take effect on 

 the young fish, he notices two trials,— one on keeping the young 

 fish in d°arkness after quitting the egg, which had no marked in- 

 fluence ; the other, on keeping them in the smallest portion of 

 water capable of covering them, in relation to the position of young 

 fish during a time of drought ; in one experiment life was pro- 

 tracted 52 hours, in another 74. 



In the 6th, on the food of the young fish, he endeavours to prove 

 that the food most suitable for them, and for which thev are best 



