MEDUSAE OF THE WORLD. 



THE SCYPHOMEDUSAE. 



INTRODUCTION. 



The present volume is a continuation of the work the two former parts of which dealt 

 with the Hydromedusae. The acknowledgments which I was privileged to render in the 

 introduction to the first volume need not here be repeated, pleasurable to me as such a repeti- 

 tion would be. Suffice it to say that the work was commenced in 1892 at the suggestion of 

 Dr. Alexander Agassiz whose generous aid enabled me to pursue these studies for many years 

 under the most advantageous conditions; and apart from the sense of personal gratitude 

 I cherish toward Dr. Agassiz I hope that enough of scientific worth may be found within 

 these volumes to cause it to appear that I have made appreciative use of the opportunities he 

 so magnanimously accorded to me. Throughout the years I have hoped that Dr. Agassiz 

 might live to see this work and that he might be pleased by this fruit of his inspiration, 

 but on March 27, 1910, the great student of the oceans died upon the sea, only a few weeks 

 before the publication of these volumes. 



Since the first two volumes passed under the press I have been most kindly aided by the 

 United States Bureau of Fisheries and by the National Museum of the United States, at 

 Washington. The authorities of the former permitted me to study the important collection 

 of Scyphomedusje recently made by the Albatross in the Philippine Islands, and those of the 

 latter institution were so courteous and helpful as to set aside for my use a table in the 

 Smithsonian building in order that I might study this collection to the best advantage. It 

 is due especially to Dr. Hugh M. Smith, Deputy Commissioner of the Bureau of Fisheries, 

 and to Dr. Richard Rathbun, Assistant Secretary of the Smithsonian Institution that I owe 

 these highly appreciated favors. 



Plates 61 and 64A and several text-figures are taken from drawings made from nature 

 by my friend, the late Prof. William K. Brooks. These drawings were most kindly presented 

 to me for publication in this work by Prof. E. A. Andrews, of the Johns Hopkins University, 

 soon after the death of Professor Brooks. They will serve as memorials of the rare skill in 

 observation and in draftsmanship of the great naturalist who made them. 



SCYPHOMEDUS.E. 



Phanerocarpa-, Eschscholtz, 1829, Syst. der Acal. 



Steganopthalma, Forbes, 1848, British Naked-eyed Medusae. 



Acraspedj^j Gegenbaur, i8!;6, Zeit. fiir wissen. Zool., Bd. 8. 



Discophora, AcASslz, L., 1862, Com. Nat. Hist. U. .S., vol. 4. 



Acraspedx, Haeckel, 1880, Systems der Medusen, Halfte 2. 



ScyphomeduSiSf Lankester, 1881, Encyclopa?dia Britannica, Ed. 9, Hydrozoa, p. 547. 



Medusiform CniJarla with tentacle-like, entodermal filaments upon the subumbrelia floor 

 of the stomach-cavity. With entodermal gonads, and without a velum such as is characteristic 

 of the Hydromedusae. Development by strobilization from scyphostoma larvae. 



There is but little evidence to support the supposition that the Sc\'phomedusK have been 

 derived from the Hydromedusae. The medusa shape of the sexual generation in both has in 

 all probability been acquired independently. Indeed, various animals have assumed the 

 external appearance and peculiar mode of locomotion by pulsation which is characteristic of 

 the medusae. Such for example are the protozoan Craspedotella and the holothurian Pela- 

 gothuria. Moreover there is reason to believe that the medusa-bell of the Narcomedusae has 



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