| OCR Text |
Show 326 MR. R. COLLETT ON CERTAIN GOBIOID FISHES. [Mar. 5, The distance between the two dorsals is at least so great that the rays of the first can never reach to the commencement of the second. The second dorsal fin has 13, rarely only 12 rays, the last of which is a double one, although not divided in many young individuals. In the full-grown female, as well as in immature individuals of both sexes, it strongly decreases posteriorly: the first is only half as long as the second and third, which are the longest; after this the length diminishes successively, and the last (the double one) has scarcely the length of the first. T h e first ray is not articulated; the remaining are all articulated ; the first and the second are single, the remaining divided at the point (the double ray only in its innermost branch). In the mature male the posterior rays are lengthened, the fin becoming almost even ; the point of the posterior rays reaches a distance of the diameter of the eye from the root of the caudal fin, this distance being considerably larger in the females and young individuals. The caudal fin has 17 articulated rays, besides a row of 10 short, feeble, unarticulated, supplementary rays on each side. All the articulated rays (with the exception of the two outermost on each side) are twice divided in the outer two thirds of the fin. The length of the fin does not exceed considerably the height of the body. Its form in young specimens, as well as in the female is always slightly emarginated, which is also the case with a great number of the males during the spawning-season; other males have the caudal fin square, with rounded corners ; and it is only in the case of the older that the middle rays are longer than the other ones, by which means the form of the fin becomes rounded. The anal fin has 14 rays, the last of which is a double ray. In its construction and position it agrees in general with the second dorsal; and having a ray more, it stretches a little further back than this. The pectoral fin has 16 articulated rays, all of which, with the exception of the outermost on each side, are divided in the outer third of the fin, and after the fourth-ray doubly divided. The form is somewhat pointed; the point is scarcely the distance of one diameter of the eye from the vent. In accordance with the rule in the generality of fishes, this fin is one of the latest developed; in a specimen with a total length of 19 millims., it consists only of a rounded flap, in which there is a vestige of a few rays. The ventral fins have their origin beneath the root of the pectorals, and consist each of 6 rays. These together form the more or less developed funnel, which is typical of the subfamily Gobiinee. When expanded, the opening of the funnel forms an oblong ring, which runs parallel with the ventral line. All the rays are three times divided down to the root, and are very movable. In the full-grown male the extreme point reaches almost as far back as the pectorals. In the female and the immature males the ventrals are very much shorter, the funnels and the outer division of the rays indistinct; the extreme point is distant more than half the length of the head from the vent. |
