INTRODUCTION. 11 



the value of chloretone as a stupefying reagent for Medusae. A few cubic 

 centimeters of a 1% solution of chloretone were usually added to the recep- 

 tacle in which the " tow " was contained, and proved most satisfactory, not 

 only for Medusae, but also for Siphonophorae. Excellent and concise direc- 

 tions for the treatment of Medusae on shipboard have been published by 

 Browne (: 06). 



In the preparation of this report I have been much assisted by having ac- 

 cess to the extensive collection of Medusae in the Museum of Comparative 

 Zoology, which, besides being rich in West Indian species, contains many of 

 the specimens from Puget Sound described by A. Agassiz ('65), as well as 

 those from the Fiji Islands reported upon by Agassiz and Mayer ('99). The 

 Pacific Medusae of the U. S. National Museum, including the Hawaiian 

 collection reported upon by Mayer (: 06), have likewise been at my disposal. 



It is a pleasure to acknowledge my obligations to the following gentlemen 

 for their assistance : — to Mr. Alexander Agassiz, to whom I am indebted not 

 only for the opportunity to accompany the " Albatross " on her cruise, but 

 for constant encouragement, advice, and criticism in the preparation of this 

 report ; to Mr. Richard Rathbun of the U. S. National Museum for placing 

 at my disposal the collections of the National Museum; to Messrs. G. H. Parker, 

 Thomas Barbour, H. L. Clark, and 0. Bryant for interesting specimens of 

 Medusae; to Mr. E. T. Browne, Dr. C. W. Hargitt, Dr. 0. Maas, and Dr. A. 

 G. Mayer, for information, and counsel on knotty questions of nomenclature. 



Museum of Comparative Zoology, 

 Cambridge, Mass., June, 1U08. 



