xxiv INTRODUCTION 



All these groups are divided into subdivisions, such as suborders, 

 subfamilies, subgenera, and even subspecies; but in the writer's 

 opinion there is very little excuse for their creation, or for their 

 continued existence, and the student will do well to let them alone 

 until he feels the need for them. 



A tautonym is a scientific name in which the name of the genus is 

 repeated as the name of the species. Thus, some authors write the 

 Latin name of the American Bison as Bwon bison; and the Anhinga 

 is Anhinga anhinga. In America, the tautonym habit is merely 

 another step toward the complete demoralization of zoological 

 nomenclature. 



A trinomial is a name in three sections, applied to a subspecies; 

 such as Felis concolor oregonensis. 



By scientific authors, species are frequently divided into sub- 

 species, or races, because in widely separated localities, animals of 

 the same parent stock sometimes are so influenced by differences 

 in climate, food, and surroundings that they assume different 

 colors, or grow larger or smaller than the type. But, no matter 

 how much individuals may differ in size and color, if it is possible 

 to bring together a collection of specimens which will show all 

 stages of variation from the type to the extremes, then the specimens 

 all belong to the same species. Thus, in passing from New York 

 to Ohio, specimens of the Gray Squirrel show all shades of varia- 

 tion, from the typical gray to black; but all belong to the same 

 species, called in Latin, Sciurus carolinensis. 



A SPECIES is an assemblage of individual animals which in at 

 least one respect are distinctly different from all others, and whose 

 peculiarities are so well marked and so constant that they can be 

 distinguished from all others without the aid of locality labels. 



When a new kind of animal is found, adult specimens of which are 

 distinctly different from those of all known species, an average 

 specimen is taken as a type, and it is described, and christened by 

 its describer. Every species should be distinguishable by external 



