A larger number of species is dealt with in this volume than in the last, but as many were procured in deep water, for instance, by Dr. Gwyn Jeffreys and Canon Norman in Shetland, or captured under difficult circumstances, it has not been possible to include so many coloured figures as could have been wished. Yet in this part economically valuable forms, such as the Arenicolids and Spionids, brightly phosphorescent types like Chaetopterus, the most cosmopolitan of all the boring groups, viz. the Polydorae and Dodecaceridsae, the complex and physiologically interesting Magelona and the Capitellidae, and, lastly, the numerous and peculiar family of the Maldanids, fall to be considered.
While some in this section lack beauty of coloration in contrast with the elegant Phyllodocidae, they, for example, Chaetopterus and Magelona, surpass these in the remarkable complexity of outline, or in special modification of internal structure. The coloured figures by my late sister, Mrs. Albert Günther, and those by Miss Walker, speak for themselves.
To my colleagues of the Old and the New World I am much indebted for many valuable works and memoirs pertaining to the Marine Annelids, and especially of the families now under consideration. Whilst a list of these will probably be given in the final part, it is right now to record the loss which everyone interested in the group has felt by the death of the veteran naturalist, Prof. Kinberg, of Stockholm. As a pioneer his name is worthy of honourable remembrance along with those of Rathke, Grube, George Johnston, De Quatrefages, Malmgren, and Langerhans.
The kind aid of Canon Norman and the late Dr. Gwyn Jeffreys in their dredging in former years in the Zetlandic seas has again to be recorded. To Dr. Allen, of the Plymouth Marine Laboratory, for southern specimens, to Prof. Arwidsson, of Upsala, for aid with the Maldanidae, to Mr. Southern for his courtesy in forwarding Irish specimens, and to Mr. Arnold Watson for a coloured and other figures of Owenia, my special thanks are due.
I have also, as on former occasions, to acknowledge the courtesy of the Librarians of the Linnean, the Royal, and the Zoological Societies of London, of the British Museum (Natural History), as well as that of the Librarians of the University of St. Andrews.
My thanks are further due to Miss Ada H. Walker for her skilful and patient work with pencil and brush. Unfortunately one or two forms were found to be British at the last moment, and hence the illustrative figures were entered with difficulty in the plates, whilst others have to be delayed for future publication.