SURFACE FAUNA OF THE GULF STREAM. 
Ce) 
floats are thrown upon the beach behind Fort Jefferson at the Tortugas in 
great numbers, forming regular windrows, and, when dry, are blown by the 
winds to the highest parts of the beach. 
The Florida species is much larger than the Mediterranean V. spirans, 
Specimens measuring nearly four inches in length are not uncommon. 
On Plate I is figured in profile, from above and below, a huge Velella, 
nearly five inches in length. This is a somewhat unusual size. The out- 
line of the mantle, seen from above, is less elliptical than in V. spirans, 
it is somewhat rectangular, with rounded corners (Pl. I, Fig. 2), and 
is also proportionally broader than in the Mediterranean species. Seen 
from above (Pl. I. Fig. 2), the color of the mantle is of a metallic bluish 
green, with a deep cobalt blue edge surrounding the outer edge of the float, 
and a similar band, forming an irregular ellipse with re-entering sides, placed 
somewhat diagonally across the float. Between these bands the color of the 
mantle passes rapidly from a yellowish green to the dark-blue inner and 
outer bands. Through the outer edge of the mantle the base of the outer 
blue tentacles of the lower side of the float can be indistinctly seen. The 
whole of the mantle is dotted with the patches of the so-called liver-cells, of a 
brownish color. The extreme edge of the dark outer part of the mantle is 
fringed with a light cobalt blue band, in which are placed the glandular 
organs of the free edge of the mantle. The free outer edge of the mantle is 
usually turned down so as to form slight indentations, or apparently sharp 
incisions in the general outlme (PI. I, Figs. 2,3). The figure from below 
(Fig. 3) shows how the edge of the mantle is carried when folded under to 
produce the incisions seen from the upper side. The mantle, where it covers 
the central part of the float, is of a light greenish blue, with a metallic lustre, 
with a few patches of liver-cells, diminishing in number towards the base of 
the keel. The greenish lines of color form concentric lines parallel with the 
chambers of the float, crossed by triangular radiating rays extending from 
the fixed edge of the mantle towards the base of the keel, dividing the float 
into irregular alternating sections of light and colored triangular spaces. 
The keel is of a delicate steel color, with a thickened edge of the mantle 
(PL. I, Fig. 2) running round it. In this the patches of liver-cells are closely 
packed together, and form dark-violet triangular patches, extending at right 
angles from the edge of the keel to the edge of the mantle. Seen from 
above the float is divided longitudinally by a long triangular band of liver- 
cells, which are seen through the float, so as to divide the float into two 
