EDITORIAL NOTE. 



The first Memoir in the present volume is a Report on the Actiniaria of the 

 Expedition, by Professor Richard Hertwig, of Koenigsberg. 



This Report is not complete, in so far as it does not embrace the whole of 

 the Challenger collection. A considerable number of specimens did not reach 

 Professor Hertwig till some time after he had completed the examination of 

 the collection originally sent to him, indeed, not till the present paper was in 

 type. Professor Hertwig has kindly undertaken to prepare a short supple- 

 mentary Report on the additional specimens here referred to. 



The Memoir has been translated from the German by Miss Nellie 

 Maclagan. 



The second Memoir is the first part of a Report on the Tunicata of the 

 Expedition, by Professor W. A. Herdman, of University College, Liverpool. 



As Professor Herdman had completed the examination and description of 

 the Ascidise Simplices, he consented to the separate publication of this 

 portion of his Report. 



The second part of his Report, which will consist of a description of the 

 Ascidias Composites and the Pelagic Tunicates, will, it is hoped, be ready for 

 publication within a year from the present time. 



The above Reports form respectively Parts XV. and XVII. of the Zoolo- 

 gical Series. Part XVI. was published in Vol. V.. Zoology. 



John Murray. 



