2 MANUAL OF ZOOLOGY 



The domestic cat, the European wild cat, the ocelot, the 

 leopard, the tiger, and the lion are animals which agree with 

 one another in the general features of their organisation 

 in the number and form of their bones and teeth, in the 

 possession of retractile claws, and in the position and 

 characters of their internal organs. No one can fail to 

 see that these animals, in spite of differences of size, colour, 

 markings, etc., are all, in the broad sense of the word, 

 " cats." This is expressed in the language of systematic 

 Zoology by saying that they are so many species of a single 

 genus. 



According to the system of binomial nomenclature intro- 

 duced by Linnaeus, each kind of animal receives two names 

 one the generic name, common to all species of the 

 genus ; the other the specific name, peculiar to the species 

 in question. Both generic and specific names are Latin in 

 form, and are commonly Latin or Greek in origin, although 

 frequently modern names of persons or places, with Latinised 

 terminations, are employed. In giving the name of an ani- 

 mal, the generic name is always placed first, and is written 

 with a capital letter, the specific name following it, and 

 being written, as a rule, with a small letter. For instance, 

 to take the examples already referred to, the domestic cat is 

 called Felis domestica, the European wild cat F. catus, the 

 leopard F. pardus, the tiger F. tigris, the lion F. leo. Thus 

 the systematic name of an animal is something more than a 

 mere appellation, since it indicates the affinity of the species 

 with other members of the same genus : to name an animal 

 is, in fact, to classify it. 



It is' a matter of common observation that no two indi- 

 viduals of a species are ever exactly alike : two tabby cats, 

 for instance, however they may resemble one another in the 

 general characters of their colour and markings, invariably 



