Family-DELPHINIDÆ.
Delphinus Fitz-Royi.
Plate X.
D. suprà niger; capitis corporisque lateribus, corporeque subtùs niveis; caudâ, pedibus, labioque inferiore, nigris; fasciis latis duabus per latus utrumque obliquè excurrentibus, nigréscenti-cinereis, hujusque coloris fasciâ, utrinque ab angulo oris ad pedem tendente.
Description.—Upper parts of the body black, under parts pure white, the two blended into each other by gray: extremity of snout, a ring round the eye, the edge of the under lip, and the tail fin, black; dorsal and pectoral fins dark gray; a broad gray mark extends from the angle of the mouth to the pectoral fin; above which, the white runs through the eye and is blended into gray over the eye; two broad deep gray bands are extended in an oblique manner along each side of the body, running from the back downwards and backwards; iris of eye dark brown. Body anteriorly somewhat depressed, posteriorly compressed; head conical, arched above; the lower lip projecting beyond the upper; eye placed above and behind, but near the angle of the mouth; breathing vent situated in the same line as the eyes—supposing a circle to be taken round the head. Teeth slightly curved, and conical; in the upper jaw twenty-eight in number on each side, and in the lower, twenty-seven.
| Ft. | In. | Lines. | |||
|---|---|---|---|---|---|
| Total length (measuring along the curve of back) | 5 | 4 | 0 | ||
| Length | from tip of muzzle | to vent | 3 | 10 | 9 |
| to dorsal fin | 2 | 6 | 5 | ||
| to pectoral | 1 | 4 | 5 | ||
| to eye | 0 | 9 | 9 | ||
| to breathing aperture (following curve of head) | 0 | 10 | 7 | ||
| to angle of mouth | 0 | 7 | 9 | ||
| of dorsal fin along the anterior margin | 1 | 0 | 5 | ||
| Height of do. | 0 | 6 | 4 | ||
| Length of pectoral, along anterior margin | 1 | 2 | 8 | ||
| Width of tail | 1 | 4 | 5 | ||
| Girth of body | before dorsal fin | 3 | 0 | 6 | |
| before pectoral fin | 2 | 8 | 2 | ||
| before tail fin | 0 | 7 | 8 | ||
| of head | over the eyes | 2 | 0 | 0 | |
Habitat, coast of Patagonia, Lat. 42° 30′, (April.)
This species, which I have taken the liberty of naming after Captain FitzRoy, the Commander of the Beagle, approaches in some respects to the Delphinus superciliosus of the “Voyage de la Coquille,” but that animal does not possess the oblique dark-gray bands on the sides of the body; it likewise wants the gray mark which extends from the angle of the mouth to the pectoral fins. In the figure the under lip of the D. superciliosus is represented as almost white, whereas in the present species it is black: judging from the figures, there is likewise considerable difference in the form. The figure which illustrates this description agrees with the dimensions, which were carefully taken by Mr. Darwin immediately after the animal was captured, and hence is correct.
“This porpoise, which was a female, was harpooned from the Beagle in the Bay of St. Joseph, out of several, in a large troop, which were sporting round the ship. I am indebted to Captain FitzRoy for having made an excellent coloured drawing of it, when fresh killed, from which the accompanying lithograph has been taken.”—D.