3."> J ZOOLOGY. 



Newfoundland in quest of the cod (Fig. 323), a large and 

 excellent fish abounding on these coasts, though not on ours, 

 the subject cannot be said to be without interest. 



494. Classification. Fishes form one of the most 

 numerous classes of the animal kingdom, and are usually 

 divided into two series, according to the nature of their 

 skeleton. 



The group or sub-class of osseous fishes is by far the most 

 numerous in genera and species. It is composed of all the 



Fig. 323. Common Cod. 



ordinary fishes, and is subdivided into six orders by cha- 

 racters in general not very important. These orders are 

 Acanthopterygii, Malacopterygii abdominales, Malacopterygii 

 sub-branchiales, Malacopoterygii apodes, Lophobranchii, and 

 Plectognathi. 



495. The plectognathi differ from all other fishes in the 

 conformation of their mouth, for in them the upper jaw-bone 

 is united to the cranium. This famil} r comprises the coflfres 



Fig. 324. Coffre, or Astracion. 



( Fiir. 32 1), which have the body covered with a kind of cuirass 

 with osseous compartments; the diodon or globe-fish, and 

 the tetrodon. which by swallowing the air become inflated 

 like a ball, are examples of this class. 



496. The lophobranchii are characterized by the struc- 

 ture of the gills. These, instead of resembling the teeth of a 

 comb, divide into little rounded tufts, fixed in pairs along the 



