G. GENERAL NATURAL HISTORY AND ZOOLOGY. 217 



just referred to, in the development of a conical tusk in the 

 lower jaw, in the similarity of the parrs to the salmon parrs 

 of the same size, and the great size of the eggs, equal in this 

 respect to those of the salmon ; in the form of the yolk sac; 

 which is elongated like that of the salmon, instead of bein^ 

 rounded like that of the trout; in their ascending streams at 

 night; in the short period of spawning; and in spawning at 

 night and lying quiet during the day, the reverse being the 

 habit of the trout, which spawns during the day and lies 

 quiet at night. The relation is, therefore, much more close 

 to the true salmon ; and the remaining question is as to 

 whether it be really the same as the true sea salmon or not. 

 Mr. Stone, however, thinks the difference in the number of 

 eggs of the Sebago salmon, as he calls it, and that of the sea 

 salmon, is a very important point. Thus, while the latter 

 produces from nine to fifteen thousand eggs per season, or an 

 average of about one thousand to each pound in weight of 

 the fish, the landlocked salmon, although of about one third 

 the weight, averages only six hundred eggs per season, or 

 about two hundred to the pound. Furthermore, there is not 

 now, nor has there ever been, any thing to prevent these so- 

 called " landlocked salmon" from going to the sea whenever 

 they preferred ; and the fact that they do not migrate is cotf- 

 sidered by Mr. Stone as strong proof that they never pos- 

 sessed the instinct to do so. 2 A, April 8, 1871, 245. 



FOOD FOR YOUNG TROUT. 



According to Dr. Slack, the well-known proprietor of the 

 Troutdale fish-breeding establishment in New Jersey, the 

 best substance with which to feed embryo trout hatched out 

 artificially consists of beef's heart, prepared by first being 

 opened that the coagulated blood may be washed away thor- 

 oughly, and then using only the pure muscular fibre. This is 

 to be finely chopped into minute fragments, so as almost to 

 form a pulp, and then, mixed with a little water, it is to be 

 washed through a fine sieve of twenty-four threads to the inch, 

 so as to prevent any minute particles from passing through. 



TAILLESS TROUT IX SCOTLAND. 



At the last meeting of the British Association some so- 

 called tailless trout were exhibited, which were said to occur 



K 



