PREFACE TO THE THIRD EDITION 



In the two former editions the " Lessons " practically 

 concluded with Polygordius as an example of tripoblastic 

 animals, and with the Fern as an example of vascular 

 plants, and the merest sketches of the higher groups of both 

 kingdoms were added (see Preface to the first edition, 

 p. viii). It has, however, been suggested to me from more 

 than one source, that the usefulness of the book would be 

 increased by expanding these sketches into somethmg more 

 comprehensible to the beginner. 



This I have done in the present edition, with the result 

 that Lesson XXVI I. of previous editions has been expanded 

 into Lessons XXVI. — XXIX., and Lesson XXX. into 

 Lessons XXXII. — XXXIV. The new matter is illustrated 

 with forty additional figures. 



I have again to thank my brother, Prof. W. N. Parker, 

 for sacrificing much time in the labour of proof correcting. 



September 1896. 



