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Show 1.54 ZOOLOGY OF TilE VOYAGE OF TilE BEAGLE. and, crossing its former course nearly at right angles, proceeds along the upper part of the side, getting lower as it approaches beneath the dorsal, to terminate at the caudal. There are also two short transverse lines ; one across the snout, connecting the loops; another across the nape, connecting the two main lines after they ha~e assumed ~he usual dire~tion. . CoLoun.-"Bcncath snow white. Above dark browmsh- black, this colour formmg a senes of broad oval rings, one within another; the outer and largest ring includes nearly the entire surface of the back and sides. The upper surface is, in addition, marked with round spots of a darker shade. Pectoral and dorsal fins yellowish brown. Iris, inner edge clouded with orange; pupil dark grecn-bluc."-D.-In its present state, there is no indication of the rings noticed above. The spots, which are small, and cover nearly the whole head, back, and sides, appear also sparingly on the basal half of the caudal, but not on any of the other fins. Habitat, Galapagos Archipelago. This species was taken by Mr. Darwin at Chatham Island, in the Galapagos Archipelago. He observes in his notes that it makes a loud grating noise. It is remarkable for the great tortuosity of the lateral line. The form of the nostrils is also rather peculiar. 4. TETRODON ANGUSTICEPS. Jen. PLATE XXVIII. T. s11,pra obsett1'e vi1·idis: capite oblongo, sttbcompt·esso, spatio interoculm·i multum contracto: cmpm·e infra ventricoso, ubique lcevissinw, duobus, in summo dm·so, cirris cutaneis parvis adornalo : ma::cillis subceqttalibus: naribus tubulosis, indivisis, apertu1 ·is duabus lateralibus : lined laterali in capite tortuosissimd : pinnd dorsali omnino ante pinnam analem ; caudali r.equali. D. 8; A. 7; C. 9; P. 15. LoNG. unc. 9. lin. 3. FonM.-Rather more elongated than the last species; especially in regard to the head, which is also more compressed upwards, reducing the space between the eyes to a narrow channel, much hollowed out, and not exceeding one diameter of the eye. Body inflatable, every where quite smooth. Jaws nearly equal, the upper one perhaps a very little in advance. Nostrils tubular, with two lateral apertures, somewhat similar to those of the last species, but more elevated. Lateral line similar, taking the same windings on the head. A little behind the transverse line on the nape, and nearly above the attachment of the pectoral, are two small skinny appendages: there is also a very minute one on each side of the tail, but none elsewhere. Dorsal wholly before the anal. Caudal square. CoLoun.-" Above dull green: base of the pectorals and dorsal black; a white patch beneath the pectorals."-D.-The colours must have very much altered from the action of the spirit, as it now appears of a nearly uniform reddish brown, only paler beneath. Habitat, Galapagos Archipelago. Another apparently undescribed species of this genus, taken by Mr. Darwin at the same place as the last. He observes in his notes that it is inflatable. |