EXPLORATION 
Or THE 
SURFACE FAUNA OF THE GULF STREAM 
UNDER THE AUSPICES OF THE COAST SURVEY. 
By ALEXANDER AGASSIZ. 
It. Parr I* 
The Porpitidee and Velelide. By ALEXANDER AGAssIz. 
(Published by permission of Carine P. Parrerson and J. E. Hinearp, Supts. U.S. 
Coast and Geodetic Survey.) 
Wuite at the Tortugas ¢ examining the structure of the coral reefs, I took 
advantage of my opportunities to study the surface Fauna of the Gulf Stream, 
and when not otherwise occupied devoted the time I could spare to complete 
the notes and drawings I had accumulated regarding Porpita and Velella 
under less favorable 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, Koélliker, and Agassiz were inclined to associ- 
ate them, and, on the other, with the Siphonophorx proper, with which, as 
* Mr. C. O. WuiTMman 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 West 
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. 
+ See Letter No, 5, ALexanpER Aaassiz to Cartite P. Parrersoy, 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 Gulf Stream. 
The Hon. Secretary of the Navy kindly allowed the commanding officer at Key West, Lieutenant Winn, 
to give me permission to occupy the loft of the Navy storehouse as a laboratory. 
