Vol. III. 



APKIL, 1893. 



Copyright 1893. All Rights Reserved. 



No. 27. 



DENOMINATIVE CHARACTER- 

 ISTICS OF FRESH WATER 

 FISHES. 



ANATOMY OF FISHES. 



(With illustration of the Black Bass.) 



Fish belong to that great branch of 

 the animal kingdom called vei'tebrates, 

 the first of the four " structural con- 

 ceptions" Cuvier, the great French 

 naturalist, found in nature and to which 

 man himself belongs. The vertebrates 

 are subdivided into four classes in the 

 following order: Fishes, Reptiles, Birds 

 and Mammalia. The structural plan 

 of the vertebrates, in the language of 

 Agassiz, is ''a backbone, with a solid 

 arch above and a solid arch below, form- 

 ing two cavities that contain all the 

 systems of organs, the whole being sur- 

 rounded by the flesh and skin. Now, 

 whether a body so constructed lies prone 

 in the water, like a Fish, or be lifted 

 on imperfect legs like a Reptile, or bal- 

 anced on two legs, while the front limbs 

 become wings, as in Birds, or be raised 

 upon four strong limbs terminating in 

 paws or feet, as in Quadrupeds, or 

 stand upright with head erect, while 

 the limbs consist of a pair of arms and 



a pair of legs, as in Man, does not 

 in the least affect that structural con- 

 ception under which they are all in- 

 cluded. Every Vertebrate has a back- 

 bone ; every Vertebrate has a solid arch 

 above that backbone, and a solid arch 

 below it, forming two cavities, no mat- 

 ter whether these arches be of hard 

 bone, or of cartilage, or even of a softer 

 substance ; every Vertebrate has the 

 brain, the spinal marrow or spinal cord, 

 and the organs of the senses in the 

 upper cavity, and the organs of diges- 

 tion, respiration, circulation, and re- 

 production, in the lower one ; every 

 Vertebrate has four locomotive appen- 

 dages, built of the same bones and 

 bearing the same relation to the rest of 

 the organization, whether they be called 

 2:)ectoral and ventral fins, or legs, or 

 Avings and legs, or arms and legs." 



It is not our purpose, however, to 

 enter into a scientific disquisition upon 

 the subject under consideration, but 

 rather to bring before the intelligence 

 of the reader a simple, yet correct, idea 

 of the external and internal anatomy of 

 fish. 



The scientist proceeds in a methodi- 

 cal manner that to the uninitiated is not 



