FAMILY TRIGLID®. 49 
GENUS DACTYLOPTERUS. Cuvier. 
The pectoral fins excessively developed, and composed of two portions, forming a large fin 
which serves as awing. Head flat, granulate. Body covered with hard carinated scales. 
Preopercle armed with a long spine. Ventrals with but four soft rays. Teeth in the 
jaws, but not on the vomer or palatines. 
Oss. This genus, as now restricted by Cuvier, comprises but two species ; one from the 
Indian ocean, and the other known from the earliest antiquity, and common in the Mediterra- 
nean sea. ‘This latter is also found along the shores of South America, and is not uncom- 
monly brought by the gulf stream along our coast as far even as the Banks of Newfoundland. 
THE SEA SWALLOW. 
DacTYLOPTERUS VOLITANS, 
PLATE XVII. FIG. 46. Back OF THE HEAD AND SCALES ENLARGED. — (STATE COLLECTION.) 
Trigla volitans. Lin. p. 498. 
Morcielago. Parra, Descripcion, &c. p. 25, pl. 14. 
Polynemus sexradiatus. Muitcuitu, Mem. pl. 4, fig. 10. Supplement Month. Mag. Vol. 2, p. 323. 
Le Dactyloptére commun, D. volitans. Cuv. et Vat. Hist. Poiss. Vol. 4, p. 117. 
Characteristics. First ray of the dorsal slightly longer than the succeeding ; a short triangular 
crest between the first and second dorsals. Length six inches. 
Description. Body cylindrical, tapering towards the tail. Head cubical or four-sided, wider 
than high. Length of the head, to the total length, as one to five. Body covered with rough 
solid scales, dentate on their free margins, and with a prominent crest on each, which is finely 
toothed (see figure). These crested scales become effaced on the abdomen. ‘They are evi- 
dent on the back, but become most conspicuous in five or six rows along the flank, which 
gradually coalesce, the upper and under row becoming more and more elevated, until they 
terminate in two highly crested plates on each side of the tail. Sixty-five scales are enume- 
rated from the opercle to the tail, and thirty-four from the dorsal to the centre of the abdomen. 
Head broader than high, flattened above with a broad furrow between the orbits, descending 
nearly vertically in front; the whole helmet being covered with deep granulations. The 
suborbital bones advance, and nearly approach in front, their whole margins being strongly 
crenated ; posteriorly they terminate in two points, with a broad emargination between them ; 
the one above forming a portion of the orbit ; the other beneath longer and more acute, termi- 
nating at the inner angle of the preopercle. The preopercle terminates in a long stout spine, 
which extends beyond the base of the pectorals, with a prominent ridge on its surface, fur- 
nished with teeth directed forwards ; its lower margin is likewise dentate. The sur-scapulars 
terminate on each side above in a very robust broad spine, which reaches as far as the penul- 
timate ray of the first dorsal (see figure). On the surface of each spine is a strong crenate 
Fauna — Parr 4. Ge 
