248 DR. J. MURiE ON THE [Mar. 26, 



A number of writers affirm, and instances shall by and by be 

 quoted where tacts are adduced in proof, that Salmon-fry can be 

 retained in fresh water alone in a healthy condition for a number of 

 years consecutively. In these cases, so to speak, the growth has 

 been arrested, and the fish have remained in the parr or smolt 

 condition. 



Some have even gone so far as to believe that such fishes, were they 

 ))ermitted to migrate to large freshwater lakes, where abundance of 

 nourishing food could be obtained, would return to their native 

 streams as large and full- developed Salmon. 



Other scientific naturalists, on the contrary, entirely ignore the 

 facts of such alleged cases, or at least doubt the accuracy of the 

 observations. 



The specific identification of a single specimen in the flesh, and 

 upon which a main argument in the present paper would be satis- 

 factorily established, is not, as some might suppose, an easy matter. 

 When such a comj)etent authority as Dr. Albert Giinther, in his 

 Preface to the Catalogue of the Fishes in the British Museum 

 (vol. vi. 18C6), states of the Salmonidce that " sometimes forms are 

 met with so peculiarly and so constantly characterized, that no ich- 

 thyologist who has seen them will deny them specific rank ; but in 

 numerous other cases one is tempted to ask whether we have not to 

 deal with a family which, being one of the most recent creation*, is 

 composed of forms not yet specifically diiFerentiated," there is surely 

 some ground for giving a decisive judgment with caution. 



Such divergence of individual opinion and the consequent diffi- 

 culty of defining specifically the varied forms of the family increase 

 the value of faithfully recorded instances bearing upon the moated 

 questions. 



The case presently to be related is one, it may be, involving con- 

 tradiction. 



History. — 1 am indebted to the Keeper of our Fish-house, 

 Tennent, for the subjoined information (taken from his Note-book) 

 regarding the receipt and subsequent hatching of Fish-ova. Our 

 Superintendent, Mr. Bartlett, has substantiated his statement. 



1. "Ova of Rhine Salmon, presented to the Gardens by Frank 

 Buckland, Esq., on the 8th of January, 1863. These ova began to 

 be hatched on the 20th of the month following (February)." 



2. "Ova of Great-Lake Trout, received February 18th, 1863; 

 began to hatch on the 1st of March." 



3. "Another batch of Great-Lake Trout came on the 28th of 

 February, and began to hatch on the 12th of March, 1863." 



4. " Mr. Gurney presented some ova of the Common Trout upon 

 February 20th, and these began to hatch on the 6th of April, 1863." 



5. " In the same year there also was received (21st of February) 

 some ova of Galway Salmon, which commenced hatching on the 

 1st of March." 



6. "Furthermore, upon the 2Sth of February, 1863, some ova 



* " No fossil true iSV/ft/io is known at present ; the nearest fossil approacliing 

 to it is a Mallotus" (footnote, ihid.). 



