Mr. J. Black walPs Notes on the Salmon. 413 



periments, not being in possession of all the particulars given by 

 the author in connexion with them ; but I may be permitted to 

 remark, that condition, considered with reference to weight, must 

 have exercised no small share of influence in the case of the grilse 

 marked by him after they had spawned in winter, and recaptured 

 in the ensuing summer as finely-formed salmon weighing from 

 nine to fourteen pounds ; in the instance of the specimen marked 

 as a grilse of four pounds in January 1842, and retaken as a sal- 

 mon of nine pounds in July; and also in that of the salmon weigh- 

 ing twelve pounds, marked on the 4th of March, after it had 

 spawned, and recaptured on the 10th of July, weighing eighteen 

 pounds. 



For the following table of the dimensions and weight of salmon 

 differing in condition I am indebted to my brother, Mr. Thomas 

 Blackwall. 



Length in inches. Girth in inches. Weight in pounds. 



23 13 5 



26 12 ,.. 5 



28 — 5 



26 13 7 



29 14 7 



29 15 8± 



31 15 9 



28 18 11| 



33 15§ Ill 



35 17£ 15| 



34 18 16 



36 19| 18£ 



39 184 18* 



36 20 20 



42 18 21 



39 20± 23 



34 13 — 



The salmon which ascend the Conway are frequently infested 

 externally by the Caligus curtus of Miiller, and internally by En- 

 tozoa, three perfectly distinct species being sometimes found in 

 the intestines of the same individual. These internal parasites 

 abound in salmon newly arrived in the fresh water ; but in various 

 specimens which I have examined in March, when they had 

 spawned and were about to return to the sea, scarcely any were 

 to be seen. My observations, however, are too limited to warrant 

 the deduction of any general conclusions in relation to this curious 

 subject, which certainly merits further investigation. 



P.S. I have ascertained by repeated dissections of the young 

 of the Salmon Trout, Salmo trutta, that the males of that species 

 shed their milt before they descend to the sea, but that the fe- 



