ii THE VOYAGE OF H.M.S. CHALLENGER. 



In the meantime I found many opportunities of continuing my researches into the 

 Siphonophorse during the numerous journeys which I undertook for the purpose of 

 completing my System der Medusen, and to which I made some reference in 1879 in 

 the preface to that monograph. I also collected much valuable material in the 

 different museums which I visited for the same purpose. A further supply of 

 specimens, and among them many new and instructive forms, were received from 

 various travellers, and notably from Captain Heinrich Rabbe of Bremen. Lastly my 

 journey to India furnished me with a long wished-for opportunity of becoming 

 acquainted with the rich though little known Siphonophoral fauna of the Indian Ocean ; 

 on the journey out to Ceylon (via Bombay), on my return home (via Socotra), and 

 especially in the expeditions which I made from Belligemma and Matura, I observed a 

 number of new genera, some of which were exceedingly interesting (November 1881 to 

 March 1882). At the same time I was able to extend my earlier observations upon the 

 development and metamorphosis of the Siphonophorse. 



Valuable systematic contributions were also derived from the study of the excellent 

 original drawings and the manuscripts of Mertens, of which Brandt gave a short 

 account in 1835. I am highly indebted to Professor Alexander Strauch in St. Petersburg 

 for the opportunity of examining these drawings which Mertens took in 1827 from living 

 Siphonophorse in the North Pacific, and which, unfortunately, have never been published; 

 they are among the best and most lifedike representations of the class that have ever 

 been produced. 



I take this opportunity of expressing my best thanks to those gentlemen who have 

 assisted me in this investigation, especially to those travellers and directors of museums 

 who have furnished me with material. By their aid I have been enabled to extend our 

 knowledge of this group, and by the discovery of new morphological types to bring it to 

 a certain degree of completeness. I am especially indebted to my honoured friend, 

 Dr. John Murray, who with the greatest liberality offered to me all the Sipkonophorze 

 collected by himself, and gave me permission to incorporate my own rich materials 

 in this Monograph. My sincerest thanks are due also to the excellent artist, Mr. 

 Adolph Gdtsch, who, aided by his morphological interest and unwearying care, executed 

 the chromo-lithographic Plates of this Report with such perfection, that they will give 

 a complete idea of this most wonderful class of animals. 



