16 CATECHISM OF 



than the tusk of the elephant, and the oil which 

 it yields, though small in quantity, is much va- 

 lued. By the Greenlanders its flesh is much re- 

 lished ; with its fat they supply their lamps ; of 

 the tendons they make excellent thread, and of its 

 teeth, hunting implements, or stakes, for the con- 

 struction of their huts. 



CHAPTER III. 



Of Cartilaginous Fish. 



Q. BY what peculiarities are Cartilaginous Fish 

 distinguished ? 



A. Fish of the Cartilaginous kind have not 

 bone as the Cetaceous and Spinous fish, but 

 their muscles are supported by a soft substance, 

 resembling gristle. Like the first class, they are 

 furnished with lungs, and with gills like the last, 

 so that they can breathe through either one or the 

 other, as they may have occasion to continue 

 above or below the water. 



Q. What are the principal divisions of this class ? 



A. Cartilaginous fish are divided into 1. those 

 of the Shark kind ; 2. those of the Flat Fish kind; 

 3. those of the slender Snake-shaped kind ; 4. the 

 Sturgeon and its varieties. 



