Three genera: Xenocypris and Paracanthobrama from China; and Mystacoleucus from Sumatra.
VIII. Leuciscina.—Anal fin short or of moderate length, with from eight to eleven branched rays, not extending forwards to below the dorsal. Dorsal fin short, without osseous ray. Lateral line, if complete, running along, or nearly in, the middle of the tail. Mouth generally without barbels. Pharyngeal teeth in a single or double series.
Leuciscus.—Body covered with imbricate scales. Dorsal fin commencing opposite, rarely behind, the ventrals. Anal fin generally with from nine to eleven, rarely with eight (in small species only), and still more rarely with fourteen rays. Mouth without structural peculiarities; lower jaw not trenchant; barbels none. Pseudobranchiæ. Pharyngeal teeth conical or compressed, in a single or double series. Intestinal tract short, with only a few convolutions.
The numerous species of this genus are comprised under the name of “White-fish;” they are equally abundant in the northern temperate zone of both hemispheres, about forty species being known from the Old World, and about fifty from the New. The most noteworthy species of the former Fauna are the “Roach” (L. rutilus, see Fig. [21], p. 50), common all over Europe north of the Alps; the “Chub” (L. cephalus), extending into Northern Italy and Asia Minor; the “Dace” (L. leuciscus), a companion of the Roach; the “Id” or “Nerfling” (L. idus), from the central and northern parts of Continental Europe, domesticated in some localities of Germany, in this condition assuming the golden hue of semi-albinism, like a Gold-fish, and then called the “Orfe;” the “Rudd,” or “Red-eye” (L. erythrophthalmus), distributed all over Europe and Asia Minor, and distinguished by its scarlet lower fins; the “Minnow” (L. phoxinus), abundant everywhere in Europe, and growing to a length of seven inches in favourable localities. The North American species are much less perfectly known; the smaller ones are termed “Minnows,” the larger “Shiner” or “Dace.” The most common are L. cornutus (Red-fin, Red Dace); L. neogæus, a minnow resembling the European species, but with incomplete lateral line; L. hudsonius, the “Spawn-eater” or “Smelt.”
Tinca.—Scales small, deeply embedded in the thick skin; lateral line complete. Dorsal fin short, its origin being opposite the ventral fin; anal short; caudal subtruncated. Mouth anterior; jaws with the lips moderately developed; a barbel at the angle of the mouth. Gill-rakers short, lanceolate; pseudobranchiæ rudimentary. Pharyngeal teeth 4 or 5.-5, cuneiform, slightly hooked at the end.
Fig. 274.—The Tench (Tinca tinca).
Only one species of “Tench” is known (T. tinca), found all over Europe in stagnant waters with soft bottom. The “Golden Tench” is only a variety of colour, an incipient albinism like the Gold-fish and Id. Like most other Carps of this group it passes the winter in a state of torpidity, during which it ceases to feed. It is extremely prolific, 297,000 ova having been counted in one female; its spawn is of a greenish colour.
Leucosomus.—Scales of moderate or small size; lateral line present. Dorsal fin commencing opposite, or nearly opposite, to the ventral. Anal fin short. Mouth anterior or sub-anterior; intermaxillaries protractile. A very small barbel at the extremity of the maxillary. Lower jaw with rounded margin, and with the labial folds well developed laterally. Gill-rakers short; pseudobranchiæ. Pharyngeal teeth in a double series.
A North American genus, to which belong some of the most common species of the United States. L. pulchellus (the “Fall-fish,” “Dace,” or “Roach”), one of the largest White-fishes of the Eastern States, attaining to a length of 18 inches, and abundant in the rapids of the larger rivers. L. corporalis (the “Chub”), common everywhere from New England to the Missouri region.