[Jordan and Evermann, 1896-1900, p. 898.]
The most interesting character of the leather jacket, and one which places it at a glance, is that the rear part of its soft dorsal fin back from the 7th ray, and also its anal fin back from the 5th ray, is broken, as it were, into a series of 12 low nearly separate finlets, the ray in each of which is subdivided at the tip like the hairs of a little brush. We need only note further that its body is about 3½ times as long as it is deep, very strongly flattened sidewise, and thin, being only about one-third as thick as it is deep; its upper jaw bone reaches back about as far as the rear edge of the eye; its snout is moderately pointed; its caudal peduncle very slender, with a low, inconspicuous keel on either side. Its first dorsal fin is reduced to about 5 separate spines, each with small fin membrane and its second dorsal has about 20 rays; its soft anal fin, also of about 20 rays, is preceded by two stout and conspicuous spines, forming, together, a separate finlet. Its lateral line is nearly straight, and its [page 381] scales are very small, and imbedded in the skin, which is corrugated with a great number of short, fine, longitudinal ridges, giving it a leathery appearance, hence its common name.
Bluish above, silvery below, with yellow fins.
The largest are about 12 inches long.
Common on both coasts of tropical America; northward to New York and southern Massachusetts (Woods Hole), reaching the southwestern part of the Gulf of Maine as a stray.
The only record of this southern fish within the Gulf is of one taken in a trap off the outer beach at Chatham, Cape Cod.