276 



correspond in every way to those of tlie same age in the natural 

 streams and pools of the river. He liad previously ascertained 

 and stated, that young salmon remain in their native river for two 

 years (under the names of parrs, pinks, fingerlings, &c.), and du- 

 ring that period, or till near its close, he applies to them the name 

 of parr, as that by which they are usually designated in Scotland. 



The hatching of the ova is regulated in a great measure by the 

 temperature of the season^ In severe winters, the principle of life 

 is slowly developed. He found, by experiment, that spawn placed 

 in a stream of spring water of tlie average temperature of 40', ex- 

 hibited the embryo fish (visible to the naked eye) by the end of 

 the 60th day, and was hatched on the 108th day after impregna- 

 tion Spawn deposited by the same parent on the same day in the 

 river (the average temperature of which, for eight weeks, did not 

 exceed 33"), did not exhibit visible young until the 90th day, and 

 131 days elapsed before their final hatching. Yet the departure of 

 thfe more advanced fry sea-wards does not seem to depend on the 

 variable time of hatching, — the first week of May, of the second en- 

 suing season, being a very regular period for the main body, and on 

 the occasion in question, large shoals of salmon fry were descending 

 the river on the very day (10th May) on which the young of that 

 year were only emerging from the ova. Yet the usual belief is, 

 that they migrate in the course of the same spring in which tliey 

 are hatched. 



Mr Shaw's paper is accompanied by an extensive and varied 

 collection of specimens, which exhibit the development of the 

 fry from the period of hatching until the termination of the se- 

 cond year. A parr or young salmon twelve months old, mea- 

 sures about three and three-fourth inches in length, and exhi- 

 bits what may be called the ordinary summer aspect. It corre- 

 sponds in age and'size with those which, in the natural bed of the 

 river, are denominated " May parr,' and it is these latter alone 

 (with such as have been recently hatched) that are found in the 

 river after the beginning of May, as about that period the two- 

 year-olds all migrate to the sea. May parr are to be regarded as 

 identical with the '• Pinks of the river Hodder," alluded to by Mr 

 Yarrell, but they are the produce of the preceding spring, instead 

 of being, as usually supposed, only a few weeks old. They re- 

 main all summer, and throughout the ensuing winter, in the river, 

 and, by an anomalous, or at least unusual, economy of nature, the 

 males in the course of this early period become fit for generative 



