ON 



THE ANATOMY AND PHYSIOLOGY 



OB THE 



SPONGlIADiE. 



I. OEGOOGRAPHY. 



Naturalists are deeply indebted to Dr. Johnston for 

 having, with great labour and patient research, collected to- 

 gether all the widely scattered information that existed on 

 the subject of the Spongiadae, and for having, with so much 

 sound judgment, reduced the comparative chaos of facts 

 and opinions regarding them to such a condition of order 

 as to greatly facilitate the labours of succeeding students. 

 He has displayed in the three introductory chapters to his 

 ' History of British Sponges ' such an extent of reading 

 and research, from the earliest writers on natural history 

 to the latest authorities on those subjects, such an admirable 

 and lucid condensation of the information he has thus 

 obtained, as to render them one of the most valuable and 

 satisfactory treatises on this obscure branch of natural 

 history that has hitherto been written. It would, therefore, 

 be a work of supererogation on my part to endeavour to 

 dilate on that portion of our subject, and I am satisfied that 

 I cannot do better than to recommend to students in this 

 branch of natural history the careful perusal of his intro- 



