REPORT ON THE RADIOLARIA. in 



indebted to both gentlemen for the freedom they have allowed me in the carrying out of 

 my work, and especially for the permission to include a description of all known 

 Eadiolaria in the Challenger Eeport, which has thus become a second edition many 

 times enlarged of my Monograph published in 1862. Since all previous literature 

 of the subject has been consulted and critically revised, it is hoped that this Eeport 

 will form a useful foundation for future investigations. All names of sufficiently 

 described Eadiolaria published during the first half century of our knowledge of the 

 class (from 1834 to 1884), are inserted in alphabetical order in the index at the end of 

 this work. 



In addition to the treasures of the Challenger, my own collection of Eadiolaria has 

 yielded many new forms whose description is here included. On my journeys to the 

 Mediterranean (an account of which is given in the introduction to my Monograph of 

 the Medusae), 1 have given special attention to these delicate microscopic organisms for 

 more than thirty years. Besides the various points on the Mediterranean, the Atlantic 

 Ocean at the Canaries (in the winter of 1866-67) yielded many interesting new forms ; 

 whilst my voyage across the Indian Ocean, from Aden to Bombay, in November 1881, 

 thence to Ceylon and back by Socotra in March 1882, was still more productive. In 

 particular, some extended excursions which I had the opportunity of making from 

 Belligemma and Matura (at the southern extremity of Ceylon) gave me an insight into 

 the rich treasures of the Indian Ocean. 



Most important, however, as regards the knowledge of the Indian Eadiolaria, are the 

 collections which Captain Heinrich Eabbe of Bremen has so beautifully preserved during 

 his many voyages through that region. In the neighbourhood of Madagascar and the 

 Cocos Islands more especially, and also in the Sunda Archipelago, he met with large 

 swarms of Eadiolaria, among which were many new and remarkable forms. These were 

 of special value for completing the chorology, and the more so since the course of the 

 Challenger in the Indian Ocean lay very far to the southwards. I will therefore take 

 this opportunity of repeating my best thanks to Captain Eabbe for the friendly donation 

 of his valuable collection. 



The Eadiolarian fauna of the North Atlantic Ocean, which was previously but little 

 known and only slightly increased by the investigations of the Challenger, received a 

 valuable increase from the interesting collections made by Dr. John Murray on various 

 expeditions to the Fseroe Islands (on the "Knight Errant" in 1880 and on the "Triton" 

 in 1882). A large number of new Eadiolaria were captured in the Faeroe Channel, 

 partly at the surface of the Gulf Stream, partly at various depths, and the proof was thus 

 furnished that at certain points in the North Atlantic Ocean Eadiolaria are very richly 

 developed. I am further indebted to Dr. John Murray for the free use of this important 

 material as well as for much other assistance in the carrying out of my work. Another 

 rich source of Eadiolaria I found in the alimentary canal of pelagic animals from all seas. 



