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Pectoral arch with both clavicle (so-called infra-clavicle) and cleithrum. Ventral fins inserted far back. With few exceptions (tail of Coelacanthidae, dorsal and caudal fins of Polypteridae) the dermal rays of the unpaired fins more numerous than their endo-skeletal supports, a See also:

PRIMITIVE

primitive See also:

CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character also found in the See also:

LOWER

lower Ganoids, but disappearing in the higher. SUB-ORDER I.—OSTEOLEPIDA (Including the Haplistia, Rhipidistia and Actinistia.) Pectoral fins obtusely or acutely lobate, articulating with the pectoral See also:

GIRDLE (O. Eng. gyrdel, from gyrdan, to gird; cf. Ger. Gurtel, Dutch gordel, from giirten and gorden; "gird" and its doublet " girth " together with the other Teutonic cognates have been referred by some to the root ghar—to seize, enclose, seen in Gr. )(s

girdle by a single basal endo-skeletal element.

Nostrils on the lower side of the snout. Two dorsal fins. Families: Osteolepidae, Rhizodontidae, Holoptychidae, Coelacanthidae. The scales may be rhombic and thickly coated with ganoine (Osteolepidae) or See also:

CYCLOID (from Gr. iciidws, circle, and ennos, form)

cycloid. The vertebral axis is strongly heterocercal in the Osteolepidae and Holoptychidae, and diphycercal or intermediate between the heterocercal and the diphycercal types in the other families; usually acentrous, sometimes with See also:

RING (O.E. hring; a word common to Teutonic languages; and probably cognate with the Lat. circus, Gr. KtpKOS or KpLKOS, Skt'. chakra, wheel, circle, cf. also " harangue "); in art, a band of circular shape of varying sizes, made of any material and used f

ring-like calcifications (some of the Rhizodontidae). In the Holoptychidae the pectoral fin is extremely similar to that of the Dipneusti of the See also:

FAMILY

family Dipteridae, which they resemble closely in See also:

FORM (Lat. forma)

form and scaling. Their See also:

TEETH (O.E. Eel); plural of tooth, O.E. top)

teeth are remarkable for their complicated structure, resembling that of the Labyrinthodont Batrachians. A pineal foramen is present between the frontal bones in most of the Rhizodontidae. The Osteolepidae were mostly moderate-sized fishes, the largest (Megalichthys) measuring about 4 ft. in length. These Crossopterygians first appear in the Lower Devonian, are abundant in the Upper Devonian, Carboniferous and See also:

PERMIAN

Permian; in later periods they are represented only by the more specialized Coelacanthidae, which appear in the Lower Carboniferous, and persist as See also:

LATE

late as the Upper See also:

CHALK

Chalk. SUB-ORDER II.—CLADISTIA Pectoral fin obtusely lobate, with three basal endo-skeletal elements. Nostrils on the upper side of the snout.

A single dorsal fin, formed of a See also:

SERIES (a Latin word from serere, to join)

series of detached rays. A single family: Polypteridae. The existing Crossopterygians which form this sub-order differ very considerably from the See also:

EXTINCT

extinct Osteolepida, perhaps quite as much as these differ from the Dipneusti. The ventral fins are not lobate, the vertebral See also:

COLUMN (Lat. columna)

column is well ossified and its termination is of the diphycercal type. Spiracles, covered by bony valves, are present on the upper surface of the See also:

head. The dorsal fin is unique among fishes, being formed of detached rays consisting of a spine-like fulcra! See also:

scale supporting the fringes of the See also:

ray; these rays have been regarded, erroneously, as representing so many distinct fins, or " finlets." The scales are bony, rhombic and thickly coated with ganoine. The Polypteridae are confined to tropical See also:

Africa and the See also:

Nile, and represented by two genera: Polypterus and Calamichthys, the former moderately elongate and provided with ventral fins, the latter serpentiform and devoid of ventrals. We now know ten See also:

SPECIES

species of Polypterus, from the Nile, the See also:

CONGO

Congo, the See also:

rivers of See also:

West Africa, and lakes See also:

Chad, See also:

RUDOLF (otherwise known as Basso NOROK and Gannon)

Rudolf and See also:

TANGANYIKA (a name said by V. L. Cameron to signify a " mixing-place ")

Tanganyika, and one of Calamichthys, which inhabits West Africa from the See also:

Niger See also:

DELTA (from the shape of the Gr. letter A, delta, originally used of the mouth of the Nile)

delta to the Chiloango. The largest species of Polypterus reach a length of nearly 4 ft. The See also:

young are provided with an See also:

EXTERNAL

external opercular gill very similar to the gills of larval salamanders. The air-bladder acts as an See also:

ACCESSORY

accessory breathing See also:

ORGAN

organ, although these fishes are not known ever to leave the See also:

WATER

water. The development is stated by the late J.

S. Budgett to be even more Batrachian-like than that of the Dipneusti, but the results of the study of the material collected by him shortly before his See also:

DEATH

death have not yet been published.

End of Article: ORDER I

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