X PREFACE. 



Owen. Professor Dickie, of Aberdeen, has also kindly 

 allowed me the nse of his valuable collection of northern 

 specimens of sponges. To my friend Mr. Dunsterville, of 

 Algoa Bay, I am indebted for a fine collection of the 

 sponges of that locality ; and to Mr. H. Deane, of Clapham, 

 for rare specimens of Spongilla from India. I have to 

 thank Professor Milne Edwards, of Paris, for much kind 

 assistance during my visits to the museum of the Jardin des 

 Plantes ; and also my friend Dr. A. Farre, for the liberal use 

 he has allowed me of his fine specimens of Farrea occa and 

 Euplectella cucumer, Owen ; nor must I forget my late friend, 

 Professor Edward Forbes, who kindly supplied me with seve- 

 ral rare species of British sponges. To my friend Professor 

 Grant I am, indeed, deeply indebted, especially for the use 

 of the type specimens of British species described by the late 

 Colonel Montagu, and those presented to him by the late 

 Dr. Fleming, and also of specimens of those species which 

 he had himself described, by the means of which I have 

 been enabled to recognise many species described by the 

 authors mentioned above, and also by Dr. Johnston, the 

 identity of which must otherwise have remained in much 

 doubt and uncertainty. To my late friend, Mrs. Griffiths, 

 of Torquay, and to the Rev. Walter Gregor, of Aberdeen, 

 I am equally indebted for numerous interesting species 

 collected in the neighbourhood of Torbay, and Macduff in 

 Banffshire. My best thanks are also due to Dr. Davvson, 

 of McGilTs College, Montreal, for several contributions of 

 North American marine sponges, and for specimens also of 

 Spongilla from the river St. Lawrence. Dr. Asa Gray, of 

 Boston, and Dr. J. Leidey, of Philadelphia, United States, 

 I have to thank for specimens of North American Spongillas, 

 and Mr. J. K. Lord, for the loan of similar specimens from 

 Vancouver's Island. 



