THE PELAGIC FAUNA AND FLORA. 183 
England meduse, such as Cunina (Fig. 90), Eutima, Trachy- 
nema, Eucheilota, Liriope, Zanclea, and many other species 
which have been described by MeCrady from Charleston, S. C., 
are also brought north every year along the course of the Gulf 
Stream, and during the summer are blown to the westward 
towards the New England coast and the Atlantie coast of the 
Middle States by the prevailing southwesterly winds. 
The common green turtle of Florida is caught every year in 
Narragansett Bay, and the leather-back turtle (Sphargis) has 
been caught as far north as Massachusetts Bay. 
Fig. 91. — Velella mutica. 1. 
Velella (Fig. 91) is found in large numbers in the Straits 
of Florida, between Cuba and the Florida reefs. "Thousands 
of this animal are brought by favorable winds and tides into 
Key West harbor, and are carried by the same agencies be- 
tween the Tortugas channels. They are usually seen in large 
schools, and, although capable in a smooth sea of independent 
movement by means of their tentacles, are practically at the 
mercy of the winds and currents. They are destroyed in im- 
mense numbers by even moderate waves, which upset them, 
drive them ashore, or kill them, if kept below the surface for 
any length of time. They apparently need a good deal of 
movement, for when kept in confinement they do not thrive, 
soon die, and are rapidly decomposed. The dead floats are 
thrown upon the beach behind Fort Jefferson at the Tortugas 
