NATURAL HISTORY. 



449 



always deposits her eggs in fresh water, and the young, when 

 hatched, descend to the sea, and are supposed not to return 

 again until, in their turn, they seek the fresh water in order to 

 deposit their spawn. 



Hub-order II. TREMATOPXEr. (Or. TpT/fia, a hole pierced through any- 

 thing; -rryt'w, I breathe.) 

 Family I Scyllidrc. (Gr. 2/cuAm, a Dog-fish.) 



SCYLLIUM. 



Canicula (Lat. a little Dog), the Little Spo 



The SHARKS and RAYS have no gill-covers, but the water 

 passes through five elongated apertures on each side of the head. 



The Sharks are proverbially ferocious and dangerous crea- 

 tures, and are the pest of those seas which they infest. Their 

 mouths are furnished with several rows of sharp jagged teeth, 

 which can be raised or depressed at pleasure, and which can 

 cut through a limb or even the body of a man with the greatest 

 ease. The mouth of these fishes is placed beneath the head, 

 so that a shark cannot seize a prey at the surface of the water 

 without turning on its side, which evolution often gives time 

 for its expected prey to escape. 



The LITTLE SPOTTED DOG-FISH is the most common of the 

 Sharks that visit our shores. It is principally known on 

 account of the havoc it makes among the fish during the 

 seasons of the various fisheries, for which reason it is most 

 especially detested by the unfortunate fishermen, who not un- 

 frequently, together with their expected spoil, draw up a 



