All the fin-rays, with the exception sometimes of the first in the dorsal and the first in the pectorals, soft and cartilaginous; these rays of an articulated structure, and generally more or less branched at their extremities.

(I. ABDOMINALES).

Ventrals suspended from the abdomen, and situate far behind the pectorals.

I. Cyprinidae

Mouth small: jaws weak, generally without teeth, formed by the intermaxil-laries: pharyngeans with strong teeth: body scaly: no adipose fin.

35. Cyprinus

Jaws without teeth: lips simple, with or without barbules: branchiostegous membrane with three flat rays: one dorsal: scales generally large.

(*1. Cyprinus). Dorsal long; the second ray, as well as that in the anal, a serrated spine.

(2. Barbus). Dorsal and anal short; the former with the second or third ray strongly spinous: upper jaw with four barbules; two at the angles, and two at the extremity of the mouth.

(3. Gobio). Dorsal and anal short; without spines: upper jaw with two barbules.

(4. Tinca). Dorsal and anal short; without spines: scales small, and slimy: two very short barbules.

(5. Abramis). Neither spines nor barbules: dorsal short, placed behind the ventrals: anal long.

(6. Leuciscus). Dorsal and anal short; without spines: mouth without barbules.

36. Cobitis

Jaws without teeth: lips fleshy, fitted to act as suckers, furnished with barbules: body elongated: scales small, and slimy: branchiostegous membrane with three rays: one dorsal: ventrals very much behind.

II. Esocidae

Mouth with strong teeth: upper jaw formed by the intermaxillary, or if not entirely, the maxillary without teeth and concealed in the substance of the lips: no adipose fin.

37. Esox

Snout broad, oblong, rounded, depressed; intermaxillaries forming two-thirds of the upper jaw; teeth in both jaws, as well as on the vomer, palatines, tongue, pharyngeans, and branchial arches: one dorsal; the anal opposite.

38. Belone

Snout attenuated, greatly prolonged: intermaxillaries forming the entire margin of the upper jaw: both jaws with small teeth; none on the vomer, palatines, or tongue: body elongated: a row of carinated scales along each side of the abdomen.

(1. Belone). Dorsal and anal entire.

(2. Scomberesox). Last rays of the dorsal and anal detached, forming spurious finlets.

39. Exocoetus

Head depressed, scaly: intermaxillaries without pedicles, and forming the entire margin of the upper jaw: both jaws with small teeth: branchioste-gous membrane with ten rays: a row of carinated scales forming a projecting line along the bottom of each flank: pectorals extremely large, almost as long as the body.

Siluridae

No true scales: skin naked, or covered with osseous plates: adipose Jin often present: upper jaw formed by the intermaxillaries: first ray of the dorsal and pectoral fins generally a strong articulated spine. .

(2). Silurus

Skin naked, covered with a mucous secretion: head depressed: mouth terminal; with several fleshy barbules: card-like teeth in both jaws, as well as on the vomer: dorsal small, without any sensible spine: anal very long.

III. Salmonidae

Body scaly: two dorsals; the first with all the rays soft; second small, and adipose.

40. Salmo

The greater part of the upper jaw formed by the maxillaries: one row of sharp teeth on the maxillaries, intermaxillaries, palatines, and mandibulars; two rows on the vomer, tongue, and pharyngeans: ven-trals opposite the middle of the first dorsal; the adipose fin opposite the anal: branchiostegous membrane with more than eight rays.

41. Osmerus

Two rows of teeth on each palatine, the vomer with only a few teeth in front: ventrals opposite the anterior margin of the first dorsal: branchiostegous membrane with only eight rays: scales minute.

42. Thymallus

Gape small: jaws, tongue, palatines, and front of the vomer, with very fine velvet-like teeth: branchiostegous membrane with ten rays: first dorsal long and high: scales large.

43. Coregonus

Mouth as in the last genus, but the teeth still smaller, sometimes entirely wanting: dorsal not so long as it is high in front: scales very large.

(3). Scopelus

Gape and gill-openings large: both jaws with very small teeth; the margin of the upper formed entirely by the in-termaxillaries: tongue and palate smooth: branchiostegous membrane with nine or ten rays: first dorsal answering to the space between the ventrals and the anal; second very small, with vestiges of rays.

IV. Clupeidae

No adipose fin: upper jaw formed in the middle by the intermaxillaries, which are without pedicles; at the sides by the maxillaries: body scaly.

44. Clupea

Intermaxillaries short, and narrow; sides of the jaw formed by the maxillaries in three pieces, and alone protractile: mouth with few teeth, sometimes with none: abdomen compressed, the scales on the margin forming a serrated ridge: gill-opening very large; branchiostegous membrane with from six to eight rays.

(1. Clupea). Maxillaries arched in front: gape moderate; upper lip entire.

(2. Alosa). Upper jaw notched in the middle.

45. Engraulis

Snout projecting, and sharp-pointed; intermaxillaries placed beneath, and very small; maxillaries straight and long: gape extending to behind the eyes: both jaws furnished with teeth: gill-opening extremely large; the membrane with twelve or more rays: abdomen generally smooth.

(4). Lepisosteus

Snout prolonged, formed by the union of the intermaxillaries, maxillaries, palatines, vomer and ethmoid: lower jaw equalling it: both jaws armed with sharp teeth: branchiostegous membrane with three rays: body covered with hard osseous scales: dorsal and anal opposite, placed very far back.

(II. SUBBRACHIALES).

Ventrals immediately beneath the pectorals, the pelvis being attached to the bones of the shoulder.