and on the Ova qfifte Salmon, 107 



nated have taken four days more to perfect the embryo thau 

 those impregnated in the natural way. However, this sUght 

 difiPerence in regard to time, may have proceeded from some im- 

 perfection in the process, or some little difference in the quality 

 or temperature of the water. 



That the female parr docs not spawn is und^iable ; and al- 

 though the male parr of eighteen months old is to be found ia 

 the river, with the milt flowing from it in abundance, all the 

 winter round till about the end of February, yet no instance 

 has fallen under my observation of the roe in any female of the 

 same age, or indeed of any age, having advanced to similar ma- 

 turity. The female parr may be found in the river in autumn, 

 in nearly equal numbers to the male, but the roe found in it 

 has not the most distant appearance of approaching to maturity. 

 I have also taken it at times during the whole winter, when 

 the weather was mild, and still the roe had no appearance of ad- 

 vancing ; and even up to the period of their migration, it is to 

 be found with the roe in the same immature state. The male 

 parr having got rid of the milt, and therefore having no strong- 

 ly defined sexual distinction, has led many into the mistake of 

 supposing all parrs to be mules. By a minute examination, 

 however, there may be observed two very small reddish colouj- 

 ed vessels lying on each side of the swimming bladder, which 

 runs from the neck to the vent ; which vessels formerly contain- 

 ed the milt, but after its discharge have become very difficult of 

 detection, from their minuteness and transparency. 



It has sometimes been maintained that the female parr has 

 been found in the act of depositing her spawn, but I am con- 

 vinced that those who have held this opinion have mistaken the 

 common trout for the par. Between the two tlie resemblance is 

 so close (both being marked with the transverse bars) as to be 

 a very probable source of error. If the parr was at all in the 

 i)abit of depositing its spawn in the river, or in its tributaries, 

 to which all small fish generally resort for that purpose, and if 

 we consider that nine-tenths of the small fish found in this part of 

 the river Nith are parrs, they must make some considerable 

 appearance when assembled on the streams, and therefore could 

 not escape observation. The apparent maturity of the organs of 

 reproduction in the male parr, and the decided immaturity of tlu? 



