A MONOG-EAPH 



OP THE 



BRITISH 



FREE AND SEMI-PARASITIC COPEPODA. 



INTRODUCTION. 



SINCE the publication, by the Ray Society in 1850, of 

 Dr. Baird's work on the ( British Entomostraca,' much 

 has been done by various authors in this country as 

 well as on the Continent of Europe and in America, to 

 extend our knowledge not only of the morphology 

 and physiology of the group, but also of its distribu- 

 tion, both fossil and recent. Dr. Baird's work admi- 

 rably fulfilled its purpose of gathering together what 

 was at that time known of the British species, a very 

 large amount of this knowledge being derived from 

 the painstaking researches of the author himself. 

 And though now of necessity somewhat obsolete 

 owing to the continued labours of more recent col- 

 lectors, no one who has studied the ' British Entomos- 

 traca ' can fail to have been largely indebted to Dr. 



8179 



