OCR Text |
Show 66 ZOOLOGY OF TilE VOYAGE OF THE BEAGLE. spines before the dorsal and anal fins, and which, by virtue of this character, though in the case of the former the spines are not apparent externall.y, serve manifestly to re-conduct to the section to which Licltia belongs. The d.tscov~ry of the present genus, therefore, furnishes a more completely connectmg lmk between these two groups. Rltynclwbdella and Mastacernblus agree with Paropsis, both in wanting ventrals and in having the first dorsal represented by free spines ; but the form of these two genera is so totally different in all other respects, that it is impossible they can be confounded with it. This new genus is from the east coast of South America. PAROPSIS SIGNATA. Jen. PLATE XIII. P. a?gentea, nitens, summo dorso ccerulescente ; operculo ad angul·um superiorem macula nigra signato; pinnis pectomlibus maculis duabus in. axillis et ad radices ?'adim·um, minm·ibus. B. 10; D. 5-1/33; A. 2-1/35; C. 17, et circa! accessar.; P. 21; V. 0. LoNG. unc. 9. FonM.- Body very much compressed, of a rhomboidal form, the dorsal and ventral lines rising to an angle at the commencement of the dorsal and anal fins respectively. Head a laterally compressed cone : tail becoming suddenly attenuated before the setting on of the caudal fin, without any keel at the sides. Back sharp and elevated; the greatest depth contained not more than two and a half times in the entire length: thickness only one-fifth of the depth. The length and depth of the head are equal, each being half the depth of the body. The upper and under profile meet at the extremity of the snout at nearly a right angle, the former falling in a very regular curve from the commencement of the dorsal fin. Mouth moderately large, the commissure reaching to beneath the eye, with the lower jaw projecting and of considerable strength and thickness. In each jaw a single row of very fine sharp teeth. The tongue, which is of a triangular form, free at the tip, and pointed, is rough, with some extremely fine closely shorn velutine teeth : a small triangular patch of these last teeth on the front of the vomer, and a narrow row on each palatine : pbaryngeans with rather stronger teeth. The intermaxillary is very slightly protractile. The maxillary reaches, when the mouth is closed, to a vertical from the posterior part of the orbit: it is very visible from without, having only its anterior portion concealed by the suborbital, and being much dilated at its posterior extremity, which is in shape somewhat securiform. Eyes above the middle of the cheek, and nearer the end of the snout than the posterior margin of the opercle; their diameter rather more than one-fifth the length of the head: the suborbital forms a narrow band beneath each. Nostrils half-way between the eyes and the end of the snout; the anterior orifice round; the posterior, which is the larger one, oval. Preopercle with the ascending margin nearly vertical ; the angle at bottom rounded. The opercle und subopercle together present a rounded margin posteriorly, |