XVI INTRODUCTORY REMARKS. 



no instance of Mules, or any other hybrids, being 

 capable of procreation between themselves. Diver- 

 sities of size, figure, and colour, sometimes occur 

 between individuals of the same species in a wild 

 state, and are very frequently found in a state of 

 domestication ; but the former are inconstant and 

 transient, and the latter seem dependent for per- 

 petuation on the watchful care of man ; and in both 

 cases, there is a constant tendency to revert to the 

 typical condition of the race. Such accidental devi- 

 ations are known by the term varieties. 



We cannot dismiss the arrangement of Linnaeus, 

 without noticing the simple but most happy in- 

 vention of the nomen triviale ) or specific name. Before 

 his time, Naturalists, in speaking of any particular 

 animal, were compelled to give a short description of it, 

 such as " the lesser grey Shrike, with a white spot 

 on the scapulars," " the smallest Lark with a Grass- 

 hopper's voice," which even in that age was extremely 

 awkward, and in our day of multiplied species would 

 be utterly impracticable. Linnaeus registered the 

 specific characters of the subject, and designated it by 

 a single term, which with the name of its genus 

 prefixed should at once distinguish it from all others, 

 exactly in the manner of the Christian and family 

 names of a man. Thus in the examples adduced, 

 having given the name Lanius to the Shrikes, and 

 Alauda to the Larks, he distinguished these two 

 species as Lanius Rutilus and Alauda Trivialis. By 

 this simple expedient, he conferred a benefit upon 



