INTRODUCTION. 13 



twelve (cephalothoracic) somites. The abdominal 

 segments in the Copepoda have no limb-like append- 

 ages. 



The preparation of this Monograph has involved 

 labour extending over several years, and in now bring- 

 ing that labour to a close I must express my warmest 

 thanks to all who have lent me their aid during the 

 progress of my work. Especially are my acknow- 

 ledgments due to Mr. David Robertson to whom 

 for kind and ever active help during many pleasant 

 excursions, as well as for gifts of numerous valuable 

 gatherings of Copepoda, I am very largely indebted ; 

 to the Rev. Alfred Merle Norman who with unvarying 

 kindness and liberality has placed his valuable collec- 

 tions at my disposal, to Mr. E. C. Davison, R.N., of 

 Sunderland, for many very interesting collections made 

 during the voyages of the " Porcupine " and at other 

 times; to Sir John Lubbock, Dr. Claus, and M. T. 

 Thorell for their liberal communication of information 

 and specimens. 



