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~ NATURAL HISTORY OF FISH IN GENERAL, 
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Some 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 Cartrisn, oR BoLLHEAD. 4+ (Amiurus nebulosus). 
This fish is known to zoologists as Amiuwrus nebulosus, Le Sueur; its 
scientific name, like that of all other animals and plants, is a double name, this 
being 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. marmoratus. 
All catfishes and their allies belong to a “family” called Siluridz, 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 possessed 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. 
o) 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, carrying out the movements 
. 
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