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Show 2 16 DR. A. GUNTHER ON A NEW DEEP-SEA FISH. [Apr. 1, by the true Ribbon-fishes (Trachypteridce). The fish described here, however, approaches the Ribbon-fishes in possessing the characteristics of bathybial organization in a somewhat higher degree : the bones of the head are thinner, more deeply sculptured, more flexible, and the muscular system is less developed than in L. cepedianus; on the other hand, the vertebrae are firmly united by ligamentous tissue. I take great pleasure in naming this interesting fish after Mr. Fisk, to whom we are indebted for so many additions to our knowledge of the Fauna of South Africa. LOPHOTES FISKI. (Plates XIX. & XX.) The body of this fish is very elongate and strongly compressed like that of a Regalecus ; it is nearly of uniform depth throughout, and gradually narrowing in its posterior fourth. It is impossible to say whether it possesses a separate caudal fin or tapers into a point, the extremity of the tail being mutilated. As in the other species of the genus, the vent (Plate XIX., v.) is at a short distance from the extremity of the tail, but no anal fin can be made out, possibly on account of the mutilation of this part. The head is scarcely deeper than the body, strongly compressed ; its upper part forms a low crest which is prolonged forward into an extraordinary sword-shaped process which projects far beyond the snout. Like the other bones of the skull, this process is flexible and deeply longitudinally sculptured ; thin as the blade of a knife, it is sharp-edged above and below. The dorsal fin commences on the extreme point of this process with an extremely long and compressed ray. I am unable to give the exact length and form of this ray, as only a fragment about as long as the head remains ; probably when complete it was three or four times that length and may serve either as a tactile or an attractile organ. It is connected with the following rays by membrane ; these are not of unusual length, but the succeeding rays, which are attached to the upper edge of the cephalic process, are short and widely set. From above the eye the rays become longer again, forming a fin which is about half as deep as the body underneath, and which is continued to the end of the tail. To return to the description of the parts of the head, we notice, in the first instance, the large eye, which is longer than the snout and possesses a transversely oval pupil. The mouth is rather small, obliquely ascending forward and with its cleft extending backwards to below the anterior margin of the eye. The maxillary is elongate, lamelliform, broader than the suborbital ring, which consists of two bones only. Both jaws are armed with a series of small uncinate teeth laterally, which series become double anteriorly. The opercular bones much dilated and overlapping each other. Gills well developed, a short slit behind the fourth arch. Six branchiostegals. The pectoral fin consists of thirteen rays, inserted on a broad horizontal base, and points upwards. The skin is scaleless and contains a rather thick deposit of a silvery pigment, which in some parts assumes a blackish hue, and seems to |