82 SCIENCE SKETCHES. 



In the depths of Lake Superior is a variety of 

 the great lake-trout known as the Siscowet {^Sal- 

 veliniis namayctish siskawitz), remarkable for its 

 extraordinary fatness of flesh. The cause of this 

 difference lies probably in some peculiarity of food, 

 as yet unascertained. 



