av NEW-YORK FAUNA. 
ridge. The opercle itself is very small, and covered with scales. Gill openings small, with 
six branchial rays, which are difficult to be counted. Mouth small, not terminal; the lower 
jaw shortest, and both with fleshy lips. Teeth minute, short, conical, forming a patch of 
three or four rows on each side of the jaws. Card teeth on the pharyngeals ; palate smooth. 
Eyes large, 0°4 in diameter, and 0°7 distant from each other. Nostrils double; the inferior 
small and tubular. 
The first dorsal fin composed of two nearly free and flexible filaments, which are nearly abreast 
of each other, and united near the base by a low membrane ; closely contiguous to these, but 
not united tothem by a membrane, follow four feebly spinous rays, united together by a mem- 
brane, and the rays diminishing in length backwards. Both this and the following fin are 
lodged ina groove. Between this and the second dorsal is a short immovable triangular crest, 
the “stiff spiny stump” of Mitchill. The second dorsal fin is composed of eight simple 
articulated rays, the two last of which are bifid; it terminates over the end of the anal. The 
pectorals may be described as consisting of two portions; the anterior 1°3 long, of six rays, 
with their tips free, and the fourth and fifth rays longest ; the posterior portion, or pectorals 
proper, extends nearly to the base of the caudal fin, and rounded. ‘This contains thirty rays ; 
they increase in length to the ninth; the nine following are subequal, when they rapidly de- 
crease in length, the five or six ultimate ones being exceedingly short and rudimentary. The 
ventral fins are placed under the base of the pectorals ; the first simple; the remaining four 
articulated ; the third 1°2 in length, and longest; the last ray very short and feeble. The 
anal fin commences under the third ray of the second dorsal, and contains six subequal rays. 
Caudal fin crescent-shaped, of ten entire articulated rays, and five accessory rays on each 
side ; the last of the accessories more than half the length of the external ray. 
Color. Light brown above, (darker on the summit of the head,) with irregular darker spots. 
Sides silvery, with flesh-color, which latter is predominate beneath. Dorsals grey, with 
brown spots on the membrane of the first, and the rays of the second annulated alternately 
with brown and lighter. The posterior pectorals blackish, with bluish iridescent spots ; the 
anterior dark brown, varied with black. Ventrals and anal fins flesh-colored. Caudal fin 
light brown, with irregular brownish bands, 
Length, 6°0. Depth, 1-0. 
Hin rays; D: 2.4.1.83 P. 62305) Vi. 1646 Ar GC. 10'S. 
This curious species, which presents so many striking anomalies in its structure, was first 
noticed on our coast by Parra in his Description of the Aquatic Animals of Cuba in 1787. 
Dr. Mitchill, in his Memoir on the Fishes of New-York in 1814, gave a good figure of this 
species ; and in his supplement to this memoir, in the American Monthly Magazine in 1818, 
furnished a detailed description which sufficiently establishes its identity with D. volitans. I 
am inclined to think that five is the normal number of rays in the first dorsal; as in three 
others which I obtained in the harbor of New-York, I found constantly that number. In these 
cases, however, there was but one free ray in front, terminating in a fleshy filament. The 
subiect of our examination was caught ina net in the harbor, in the month of August. If 
