I066 BULLETIN OF THE BUREAU OF FISHERIES. 



shelter and home by obtruding into the posterior end of the abdominal cavity 

 of holothurians. 



Another subject that will furnish interesting cases is courtship among 

 fishes. Many American fresh-water fishes furnish examples. The males become 

 more or less brilliant and assume bright liveries for and during the spawning 

 season and variously show themselves to the females; the best known species 

 are the sunfishes {Lepomis and Eupomotis) of diff'erent kinds, but representatives 

 of most or all families have their special modes of action. A still more elabo- 

 rate courtship was observed a decade ago (1898) by Ernest Holt among sea 

 fishes of the genus Callionymus. 



One fact, too often forgotten, is that there is considerable individuahty 

 among fishes and that there may be exceptions to most general propositions. 

 Species, for instance, may prefer certain food, but if they can not get such they 

 will act very much like human beings — take what thev can get. Yet our peri- 

 odicals, monthly as well as weekly, are often charged with bitter controversies 

 because one man makes an assertion respecting habits which is denied by 

 another who asserts that the animal in question always has certain other habits. 

 Both may be right in their observations but wrong in contending each that the 

 other is wrong. 



Such are a few of the many interesting phenomena manifested by fishes 

 and such a few of the special exceptions to general propositions. No men are 

 professionally in such excellent positions for observation of the habits of fishes 

 as are pisciculturists, and, if they would, they could add greatly to our knowledge 

 of their ways and means; that they should do so the scientific ichthyologist 

 and the practical fisherman must alike hope. 



I conclude with a recapitulation of some of the characteristics by which 

 fishes are distinguished among themselves and which may direct attention to 

 points overlooked or forgotten. Any biography of a fish that is wanting in 

 attention to any of the characteristics indicated is to such extent incomplete. 



Specific characters: 



Adults. 



Sexual differences. 



Relative size. 



Length. 



Weight. 

 General behavior: 



Character of water preferred. 



Character of ground preferred. 



SCHEDULE FOR OBSERVATION. 



General behavior — Continued. 



Manner of resting. 



Manner of swimming. 



Use of fins. 



Respiration. 



Association (in schools, etc.). 

 Feeding: 



Kind of food preferred. 



Manner of taking. 



