The accompanying figure is drawn from minute measurements.

The length of this specimen was 2.5 inches, its thickness through the thickest part 0.38.
What I had before imagined to be either a spine or fin turned out to be a pectoral fin.
It thus has two pectoral, one dorsal, and one ventral fin, properly speaking; but the greater part of the body is surrounded by some cartilaginous substance which it probably uses as a fin; under the line b c there is a curved portion of this matter, and above and attached to the fish is a line of round white silvery scales, about ten in number.
Between a and b there is another curved mass of transparent cartilaginous substance, along the bottom of which runs a spine to which is attached a fringe-like fin.

There is a spine upon the back; the eye is very prominent and bright; upon the back, between the eye and the spine, there are successive stripes of purple and burnished gold, so that this little animal is one of the most gorgeously coloured denizens of the ocean.

It swims about amongst the purple barnacles and pink nautili, seeking on the shores of these shining islands its prey, the curious formation of its mouth being admirably adapted to enable it, whilst swimming under these painted floating islands, to crop off what it lists.
There were scarcely any gelatinous animals in the sea this day; but many Janthina shells and Velella were round the ship, to which were attached barnacles of different species; amongst this group of islands numerous crabs were swimming about and running over them.

Animals resembling a wood-louse were also in the sea, swimming and running about the floating shells and barnacles.
We caught also a new species of Janthina, the float of which, instead of being nearly round and extending over the shell on each side, was spread like a spiral fold from the shell; the breadth of this fold was 0.45 inch, close to the mouth of the shell, and it gradually tapered off to a point, its length being 3.6 inches.