[ 138 ] 

 XVIII. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 67-] 

 April 26, 1855.— Sir Benjamin Brodie, Bart., V.P., in the Chair. 



THE following papers were read : — 

 " Some Observations on the Ova of the Salmon, in relation to 

 the distribution of Species ; in a letter addressed to Charles Darwin, 

 Esq., M.A.. V.P.R.S. &c." By John Davy, M,D., F.R.SS. Lond. 

 & Edinb. 



In this paper the author describes a series of experiments on the 

 ova of the Salmon, made with the intent of ascertaining their power 

 of endurance under a variety of circumstances without loss of life, 

 with the expectation suggested by Mr. Darwin, that the results might 

 possibly throw some light on the geographical distribution of fishes. 



The details of the experiments are given in five sections. The 

 results obtained were the following : — 



1 . That the ova of the Salmon in their advanced stage can be ex- 

 posed only for a short time to the air if dry, at ordinary tempera- 

 tures, without loss of life ; but for a considerable time, if the tempe- 

 rature be low, and if the air be moist ; the limit in the former case 

 not having exceeded an hour, whilst in the latter it has exceeded 

 many hours. 



2. That the vitality of the ova was as well preserved in air satu- 

 rated with moisture, as it would have been had they been in water. 



3. That the ova may be included in ice without loss of vitality, 

 provided the temperature is not so low as to freeze them. 



4. That the ova, and also the fry recently produced, can bear for 

 some time a temperature of about 80° or 82° in water, without 

 materially suflfering; but not without loss of life, if raised above 84° 

 or 85°. 



5. That the ova and young fry are speedily killed by a solution 

 of common salt nearly of the specific gravity of sea-water, viz. 1026; 

 and also by a weaker solution of specific gravity 1016. 



Finally, in reference to the inquiry regarding the distribution of 

 the species of fishes, he expresses his belief that some of the results 

 may be of useful application, especially those given in the second 

 and third sections ; inferring, that as in moist air, the vitality of the 

 ova is capable of being long sustained, they may during rain or fog 

 be conveyed from one river or lake to another adhering to some part 

 of an animal, such as a Heron or Otter, and also during a time of 

 snow or frost; and, further, that other of the results may be useful 

 towards determining the fittest age of ova for transport for the pur- 

 pose of stocking rivers, and likewise as a help to explain the habitats, 

 and some of the habits of the migi'atory species. 



"Observations on the Anatomy and Affinities of the Phyllirrho'e 

 bucephal a (Vex on) y By John Denis Macdonald, Esq., R.N. , As- 

 sistant-Surgeon of H.M.S.V. 'Torch.' 



As the true position of Peron's genus Phyllirrhoe, and even the 



