INTRODUCTION. XV11 



naturalist be referred with almost certainty to the 

 part of the sponge whence it was derived. The 

 immense variety of forms and parts are all, as much in 

 unison with each other, as the varied and numerous 

 parts of plants are in the vegetable creation, or the 

 numerous and varied forms of the bones in the higher 

 animal creation. 



In concluding, I must beg leave to return my 

 sincere thanks to the friends who have kindly assisted 

 me during the progress of this volume. I am deeply 

 indebted to my friend the Rev. A. M. Norman, for the 

 kind and liberal manner in which he has rendered me 

 most essential service by having placed at my disposal 

 for description and figuring, the whole of his extensive 

 and valuable collection of British sponges. My best 

 thanks are also due to Captain Marshall Hall, and Mr. 

 W. Saville Kent, for having placed at my service, 

 several rare and beautiful specimens of British 

 sponges acquired during their cruise in the British 

 Channel in Captain M. Hall's yacht Norna. To my 

 friend Mr. Henry Lee, and to Mr. Parfitt of Exeter, 

 my thanks are due for specimens of new species that 

 are figured in this volume. To Mr. Higgin of 

 Huyton near Liverpool, and Mr. Moore of the Free 

 Library and Museum of Liverpool, I am indebted for 

 much valuable information, and some new species 

 from their neighbouring localities. 



I am deeply indebted to my old friend Mr. W. Lens 

 Aldous the artist, for the minutely faithful and 

 beautiful representations of the British sponges, of 

 their natural size, and of the highly magnified repre- 

 sentations of their structural and microscopical cha- 

 racters. It is an astonishing fact that at the age of 

 eighty-two, when he did the drawings on stone of 

 Plates XCI and XCII, the work is as minutely 

 beautiful as the earlier plates that he executed for the 

 volume. 



