PREFACE. vii 



from my own papers or drawings by Mr Collings, who 

 has spared no pains to render the woodcuts as clear and 

 intelligible as possible. I trust my readers will not be 

 disappointed with the results. The sources from which the 

 woodcuts are taken have been in all cases acknowledged, 

 and in the cases where no source is given the illustrations 

 are my own. 



I take this opportunity of acknowledging my great 

 obligations to Professors Agassiz, Huxley, Gegenbaur, 

 Lankester, Turner, Kolliker, and Glaus, to Sir John Lubbock, 

 Mr Moseley, and Mr P. H. Carpenter, for the use of electro- 

 types of woodcuts from their works. 



I am also under great obligations to numerous friends 

 who have helped me in various ways in the course of my 

 labour. Professor Kleinenberg, of Messina, has read through 

 the whole of the proofs, and has made numerous valuable 

 criticisms. My friend and former pupil, Mr Adam Sedgwick, 

 has been of the greatest assistance to me in correcting the 

 proofs. I have had the benefit of many useful suggestions 

 by Professor Lankester especially in the chapter on the 

 Mollusca, and Mr P. H. Carpenter has kindly revised the 

 chapter on the Echinodermata. 



I am also much indebted to Dr Michael Foster, Mr 

 Moseley, and Mr Dew- Smith for aid and advice. 



1 LIBRARY 



