OCR Text |
Show 122 ZOOLOGY OF THE VOYA<1E OF THE BEAGLE. CoLOun.-(Jn spirits.) Greenish-brown, much more uniform than in either of the last two species, not deepening on the back, and scarcely becoming paler underneath. The back, sides, and rays of the fins, are finely irrorated with dusky specks, as in the M. alpinus, but not to the same extent, the specks being more thinly scattered, and here and there scarcely visible. From the same cause the fins appear paler. Habitat, Bay of Islands, New Zealand. This, which is a very distinct species of this new genus, was taken by Mr. Darwin in fresh-water in the Bay of Islands, New Zealand. It is well characterized by its more attenuated head and smaller eye, than those of either of the two others. FAMILY.-ESOCIDlE. ExocmTus EXSILIENS. Bl. ? Exocrotus exsiliens, Bl. Ichth. pl. 397. FoRlll.-llcad about one-sixth of the entire length, and approaching to the form of a parallelopipcd; very much flattened on the crown and between the eyes quite to the end of the snout, broader above than beneath, so that the cheeks are beyond the vertical inclining inwards at bottom. Snout short: mouth not much cleft; when shut, the jaws are equal, and the commissure of the lips appears to extend to beneath the anterior margin of the eye, but the maxillary, which retires completely beneath the suborbital, does not reach so far: when the mouth is open, the maxillary becomes vertical, and the intermaxillary being scarcely at all protractile, the lower jaw is a little the longest. Teeth very minute: a row, scarcely visible, along the forepart of the intermaxillary, but not extending to the sides of the jaw : none that can even be felt in the lower jaw, or in any other part of the mouth. Tongue rounded, and free at the tip. A loose veil of skin hangs down in front of the palate, from immediately behind the teeth in the upper jaw. Eyes round, and very large ; the upper part of the orbit reaching to the line of the profile, and forming a slightly salient ridge : their diameter very nearly one-third the length of the head; between them and the end of the snout is two· thirds of a diameter ; the distance from one to the other across the crown is one diameter and a quarter. The nostrils consist of one large round orifice a little in advance of the eyes. The membrane of the opercle forms a slightly salient angle backwards, near the upper part of the gill-opening. Scales large, of a somewhat irregular form, approaching to obion~, nearly twice as broad as long, the posterior margin with three or four incisions near the middle, and a few rather indistinct nearly parallel striw on the surface of the basal portion ; in others these striro converge to form a small but very regular fan; and the scales appear to vary a good deal on different parts of the body. . The pectorals reach exactly to the base of the lateral caudal rays; the first two rays are s~mple, and all the others branched ; first ray of all not half the length of the fin. Dorsal so ~1tuate as to leave a space between it and the end of the fleshy part of the tail about equal to 1ts. ow~ lengt~ ; the first ray simple, the others branched; the last prolonged beyond those wh1ch 1mmed1ately precede it so as to form rather a point backwards. Anal similar to the |