EXPLORATION 



OF THE 



SURFACE FAUNA OF THE GULF STREAM 



UNDEE THE AUSPICES OF THE COAST SURVEY. 

 By ALEXANDER AGASSIZ. 



ni. Part I.* 

 Tlie PorpUidce and Velellklce. B>j Alexander Agassiz. 



(Published by permission of Carlile P. Patterson and J. E. Hilgard, Supts. U. S. 



Coast and Geodetic Survey.) 



While at the Tortugas f examining the structure of the coral reefs, I took 

 advantage of my opportunities to study the sui'face Fauna of the Gulf Stream, 

 and when not otherwise occxipied devoted the time I could spare to complete 

 the notes and drawings I had accumulated regarding Porpita and Velella 

 under less flivorable circumstances at other points of Florida, at Newport, 

 and on board of the '' Blake." These notes are now published, as giving the 

 principal points on the Natural History of a small and limited group of 

 Oceanic Hydroids, interesting from their affinities, on the one side, to the 

 Tubularians, with which Vogt, Kolliker, and Agassiz were inclined to associ- 

 ate them, and, on the other, with the Siphonophorte proper, with which, as 



* Mr. C. 0. Whitman was sent to Key West this spring in hopes of obtaining the material necessary 

 to complete this memoir, and at the same time to investigate anew the whole subject of the structure and 

 functions of the so-called yellow cells. Although Mr. Whitman spent six weeks at Key West, he was 

 unable to accomplish the object of his trip, not a single Velella appearing in the harbor of Key AVest 

 during the whole of his visit. I have therefore thought it advisable not to delay the publication of the 

 descriptive part of this memoir any longer, and to complete it when the necessary preparations could be 

 finished. 



f See Letter No. 5, Alexander Agassiz to Carlile P. Patterson, on the explorations in the vicin- 

 ity of the Tortugas in 1881. Bull. M. C. Z., VIIL, No. 3, p. 145. I spent the months of March and 

 April, 1881, at Key West and at the Tortugas, under the auspices of the United States Coast Survey, the 

 late Mr. Patterson, the Superintendent, having kindly placed at my command a steam launch while 

 engaged in examining the distribution of corals and studying the surface fauna of the G>df Stream. 

 The Hon. Secretary of the Navy kindly alL^wed the commanding officer at Key West, Lieutenant Winn, 

 to give me permission to occupy the lolt of the Navy storehouse as a laboratory. 



