PEEFACE TO THE SECOND EDITION. 



The attempt to encourage practical work in Biology by means of clear figures briefly explained, and 

 accompanied by instructions for the examination of specimens, has evidently been received with 

 favour, since a second edition of the "Biological Atlas" has been called for witliin a year of 

 publication. 



Both Text and Plates have been carefully revised, and such alterations and improvements 

 made as will tend to render it still more serviceable. However, few changes have been found 

 necessary. 



The colouring of the Animal portion of the work has been somewliat altered, in order to 

 bring it into harmony witli tliat of the " Zoological Atlas," to which tlic present work may be 



regarded as an introduction. 



D. M'A. 



Edinburgh, April 1881. 



