TEMPOBABY PREFACE 



The present Part contains a larger number of species than Part II of the previous 

 volume, and the majority are more or less brilliantly coloured, not a few, for example, in 

 the PhyllodocidaB, Hesionidge, and Syllidse being amongst the most beautifully ornamented 

 Invertebrates; indeed, many vie with the gaudy tints of butterflies and birds or the 

 burnished splendour of beetles. Fortunately some of the finest of them had been 

 drawn from life by the late Mrs. Gimther (Roberta Mcintosh), and their softness and 

 beauty did not suffer at her hands. 



It is perhaps well to note that the author does not feel warranted in adopting any of 

 the recent classifications of the Polychaata, e. g. that of Professor Benham ( £ Cambridge 

 Natural History,' ii, 1896), which has certain features of Levinsen's classification, because 

 none relieves the difficulties encountered in the older and more simple classification into 

 errant and sedentary forms by Audouin and Edwards. Thus in such a system as 

 Benham's, incongruous families are grouped together (e. g. the Nephthydidse between the 

 Nereidse and Amphinomidse), and the arrangement has the support neither of structure 

 nor development. The Polychseta, indeed, do not lend themselves readily to the 

 systematist, and it is safer at present to place the families in series according to their 

 natural and structural relationships, reserving further consideration of the subject for 

 the summary. There are notable differences in the structure of the body-wall, the 

 arrangement of the great nerve-cords and the neural canals, the digestive system and 

 other features, but even these do not readily conduce to systematic arrangement. They 

 are thus in contrast with the Nemerteaus, the classification of which in 1868-9 on a struc- 

 tural basis has never been disputed, though modern nomenclature may sometimes obscure 

 the original facts. 



Dr. Goodrich has kindly drawn the segmental organs typical of the Nephthydidse, 

 and his experience of these is great. 



I have to thank Dr. Allen, the Director of the Plymouth Marine Laboratory, who 

 exerted himself to procure such of the southern types as were not readily obtainable in 

 the fresh condition elsewhere. 



To Miss A. H. "Walker, the artist who has faithfully aided me throughout the work 

 on the Annelids, special acknowledgments are due. Her pencil and brush have been of 

 great service. 



I have to acknowledge the courtesy of the Carnegie Trust in having given aid for 

 three years in regard to the artist and in section-making. Without such help it would 

 have been impossible to overtake the work in time for issue in 1907. Moreover, the 



