INIRODUCTION 



characteristics; but they breed with one an- 

 other and are more Hke each other than 

 they are like other wolves. The prairie wolf 

 or coyote {Canis latrans), in contrast, is 

 smaller and more slender, with a body about 

 49 inches long, a tail about 16 inches long, 

 and a weight of only about 25 pounds. Its 

 color is tawny, clouded with black, and its 

 tail is tipped with black. Timber wolves and 

 prairie wolves, as their common names indi- 

 cate, live in different types of habitats. 



The following is a good definition of a 

 species: A species may be defined as con- 

 sisting of groups of interbreeding natural 

 populations, which may differ markedly 

 among themselves, yet resemble each other 

 more closely than the members of any other 

 groups, and which are reproductively iso- 

 lated from other such groups. 



Origin of modem classification 



Many attempts to classify animals were 

 made before the present system was per- 

 fected. The Greek scientist Aristotle (384- 

 322 B.C., p. 652) attempted to classifv ani- 

 mals according to their similarities in 

 structure and succeeded so well that practi- 

 cally no improvements were made until the 

 time of Linnaeus (1707-1778, p. 654). This 

 Swedish scientist, instead of giving animals 

 common names which might be used for 

 different species in different localities, estab- 

 lished a universal system of classification; 

 this is the binomial nomenclature still in 

 use, and gave for each species a concise de- 

 scription in Latin. He succeeded in listing 

 4378 different species of animals and plants. 

 His greatest work entitled Systema Naturae 

 was published in 1735. It passed through 12 

 editions, and the tenth (1758) has been 

 agreed upon as the basis for zoological no- 

 menclature. The work of Linnaeus stimu- 

 lated other naturalists to discover and name 

 new species of animals. At first this was the 

 only end in view, but at the present time 

 taxonomists are interested mainly in the 

 evolution of animals in general, and espe- 

 cially in tlie groups which they are studying. 



Rules of nomenclature 



In 1901 the International Congress of 

 Zoology organized an International Commis- 

 sion on Zoological Nomenclature, which has 

 served since that time. The Commission has 

 prepared a set of International Rules of 

 Zoological Nomenclature; these rules apply 

 to family, subfamily, generic, subgeneric, 

 specific, and subspccific names. They cover 

 the formation, derivation, and correct spell- 

 ing of zoological names, the author's name, 

 the law of priority and its application, and 

 the rejection of names. According to these 

 rules, zoological and botanical names are 

 independent; and the same genus and spe- 

 cies name may be applied to both an animal 

 and a plant, although this is not recom- 

 mended. Scientific names must be Latin 

 or Latinized. Family names are formed by 

 adding idae to the stem of the name of the 

 type genus. Generic names should consist 

 of a single word, written with a capital 

 initial letter, and italicized. The names of 

 species are adjectives, agreeing grammati- 

 cally with the generic name, or substantives 

 in the nominative, in apposition with the 

 generic name, or substantives in the geni- 

 tive; they should be italicized. The author 

 of a scientific name is the first person to 

 publish the name with a definition or de- 

 scription of the organism. If a new genus is 

 proposed, it is necessary to publish a de- 

 scription of it, to designate a type species of 

 the genus to describe it, and to tell the col- 

 lection in which it has been placed. The list 

 of International Rules of Zoological Nomen- 

 clature was published in a text titled Pro- 

 cedure in Taxonomy, 1956, by Schenk and 

 McMasters. 



Derivation of terms 



Every subject has its own vocabulary 

 which must be learned by the student. New 

 terms have more meaning and are easier to 

 remember if their derivation is known. For 

 this reason, the derivations of many of the 

 common scientific terms used in zoology are 



