NATURAL HISTORY OF FISH IN GENERAL. 



Same little acquaintance with the elements of Ichthyology is necessary for 

 the proper understanding of the scientific terms used by naturalists in describing 

 Fish, and comparing them with each other. This may be acquired by the 

 attentive examination of any common form like our ordinary Catfish or Bull- 

 head (fig. 1). 



Fig. 1. — Common Catfish, or Bcllhead. | (Amiurus nebulosus) 



This fish is known to zoologists as Aviiurns nebulosus, Le Sueur ; its 

 scientific name, like that of all other animals and plants, is a double name, this 

 baing necessary to indicate the particular species to which it belongs, for there 

 are other kinds of catfish in North America sufficiently like this to be 

 united with it in the same " genus " Amiurus. The specific name " nebulosus " 

 was given by Le Sueur to this particular kind on account of its yellowish 

 brown skin being often clouded by black, but the colouration is very variable, 

 and there appears to be in the South a mottled variety sometimes regarded 

 as a distinct species, but probably only a geographical variety or sub-species, the 

 name of which is written A. nebulosus var. viarmoratus. 



All catfishes and their allies belong to a " family " called Siluridse, which 

 contains very numerous genera in the fresh waters of the tropics of both the Old 

 and New Worlds, and which, with a host of other families po.ssessed of a well 

 formed bony skeleton, belongs to the sub-division Teleostei of the class PISCES 

 — one of the primary divisions into which all back-boned or vertebrated animals 

 are divided. 



With all other vertebrates then, the catfish shares certain essential characters, 

 such as the possession of a brain and spinal cord protected by a skull and spinal 

 column. Of these, the skull serves in addition for the protection of the nose, eyes and 

 ears, as well as for masticating the food, and, in the fish, caiir^'ing out the movements 



