viii PREFACE. 



rich in species than himself, sent such sponges and Htho- 

 phytes as he considered to be rare or undescribed, from the 

 coast of Yorksliire ; I received many others from the 

 shores of the south of England from Mr J. C. Bellamy, 

 the author of the " Natural History of South Devon ;" 

 and from my much respected friend the Rev. David 

 Landsborough of Stevenston in Ayrshire those which occur 

 on tlie western coast of Scotland came uncalled for. For 

 assistance of a similar kind I must likewise acknowledge 

 my obligations to Miss Ellen Forster of Teignmouth, Dr 

 Coldstream of Leith, Mr Embleton, Surgeon, of Embleton, 

 the Rev. Dr Fleming of Aberdeen, Dr P. W. Maclagan, 

 Mr T. G. Rylands of Bewsey House, near Warrington, Mr 

 William Jackson Jun., Dundee, and Mr Alder of New- 

 castle. 



I have done my best to arrange and describe the materials 

 thus furnished me, but there is no affectation of modesty 

 when I express myself dissatisfied with ray own performance ; 

 and it would give me unfeigned pleasure to be able to assure 

 my readers that an abler hand would soon dispossess me of 

 this field of my choice and occupancy. Naturalists are 

 looking to Mr J. S. Bowerbank for much novel discovery 

 relative to the structure and functions of this hitherto ne- 

 glected tribe ; and the descriptions which he has given in 

 this volume of Pachymatisma Johnstonia and of Dysidea 

 fragilis are so excellent in every respect, that it will be a 

 matter of regret should this eminent naturalist decline to 

 publish a history of the class in general. To him I am un- 

 der deep obligations for assistance which he has given with 

 an alacrity and kindness that tempted to very frequent ap- 

 plications for it. 



For much kind aiJ, more particularly in drawing up the 



