Studies on the morphology of the gills and gill arches with reference to the blood supply in Notopterus motopterus and Colisa fasciatus.

The morphology of the gills, with their blood supply have been described in Notopterus notopterus and Colisa fasciatus in some detail. Gills are curved and perforated on the dorsolateral and ventrolateral wall of the pharynx. The gills consist of 2 rows of filaments which are stacked one above the other to form a space. The gill filaments are smaller on both the ends and larger in middle. The gill filaments are of pink colour as they are supplied with blood. Gill rakers are large in size in Notopterus notopterus while they are small in Colisa fasciatus. 3 pairs of basibranchials are present in Notopterus notopterus which are covered by median membranous bony plate while 2 basibranchials are present in Colisa fasciatus. 3 pairs of hypobranchials are present in both fishes. 5 pairs of ceratobranchials are present in which Vth ceratobranchial bears teeth. 4 pairs of epibranchials are present. 3 pairs of pharyngobranchials are present in which the tip of the IVth pharyngobranchial bears minute teeth in Notopterus notopterus while in Colisa fasciatus IInd and IIIrd pharyngobranchial bear minute ones. One afferent branchial vessel is present in Notopterus notopterus and Colisa fasciatus in each gill like in other teleostean fishes. One efferent branchial vessel is present in each gill of Notopterus notopterus while in Colisa fasciatus 2 efferent are represented in each gill.