Friday 18 May 2012

OSTEICHTHYES-BONY FISH

SUBCLASS-SARCOPTERYGII
Paired fins leg-like with a fleshy,bony central axis covered by scales.
Dorsal fins.
Caudal fin hreterocercal with an epichordal lobe.
Olfactory sacs usually connected to mouth cavity by internal nostrils or choanae.
Fleshy or lobe-finned or air breathing fish.
Divided into two superorders .ORDER 1. CROSSOPTERYGII
Paired fins lobate.
Caudal fin three lobed.
Premaxillae and maxillae present.
Internal nares present or absent.
Spiracles present.
Air bladder vestigial.
Primitive fleshy-finned extinct fishes. Latimeria. ORDER 2. DIPNOI
Median fins continuous to form diphycercal tail.
Premaxillae and maxillae absent.
Internal nares present and spiracles absent.
Air bladder single or paired,lung like e.gEPICERATODUS,PROTOPTERUS LEPIDOSIREN.

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