ITxEFACE TO THE SECOND YOLUiAlE. 



In the Preface to tlio First Volume I briefly alhulcd to the diiiercnt 

 arrangement of the present from previous editions of this Avork, 

 one reason for which being the mucli larger number of species 

 of animals and plants now enumerated. Tlie difference iu this 

 respect, between the edition of 18G0 and the present, may be 

 thus contrasted : 



The above figures will serve to explain the great inequality in the 

 treatment of some Classes of animals and plants. It woxdd have 

 been wholly out of the question within the limits at my disposal 

 to have attempted the same amount of detail in all cases, that 

 I have ventured on in some. With the Invertebrata for example, 

 little has been attempted, beyond a list of species, and their distri- 

 bution, without any attempt at descriptive notices. The number 

 of species of Invertebrata now given is alone sufficient to show 

 how impossible, in a work of this character, any attempt at 



