Gill Arches


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Gill Arches

 

the system of skeletal elements of the pharynx in cyclostomes and fish. Each gill arch embraces the pharynx in a half-ring. The majority of present-day fish have five gill arches; cyclostomes and some sharks have up to seven. In bony fish the number of gill arches may be reduced to three with the reduction of the posterior ones. Cyclostomes, cartilaginous fish, sturgeon, and dipnoans have cartilaginous gill arches; bony fish have bony gill arches.

Fully developed gill arches offish consist of four movably united segments. In bony fish the fifth gill arch, which is called the subpharyngeal bone, is usually rudimentary, but sometimes (in cyprinoids) bears teeth and is very powerful. In terrestrial vertebrates, the superior segments of the gill arches are reduced; the inferior ones participate in the formation of the subglossal apparatus and become the laryngeal cartilage.

REFERENCES

Severtsov, A. N. “Morfologiia vistseral’nogo apparata elasmobrankhii.” Sobr. soch., vol. 4. Moscow-Leningrad, 1948.
Gimmerreikh, G. A. “Vistseral’nyi apparat osetroobraznykh kak organ priema pishchi.” In Voprosy evoliutsionnoi morfologii pozvonochnykh. Moscow, 1963.
References in periodicals archive ?
Few studies had been done to determine whether all of the gill arches play an equal part in gaseous exchange or whether more of the respiratory current passes over some gill arches than others.
Later, as the gill arches enlarged, the gill rakers also enlarged, became longer, increased in number and became more complicated in shape due to the addition of side processes.
However, for Benthobatis kreffti there are no descriptive data for the ventral gill arches and the scapulocoracoid, and the present study intends to complement the anatomical information of the species, through the analysis and comparison of these structures.
The results of the present study demonstrated that the characteristics of the gill rakers (rakers and spines length, distance between rakers and spines) may vary between gill arches of the same species, and also with the fish size.
Densities increase slightly on the gill arches (approximately 1600 denticles per c[m.
Some attention to the structure of the original connection between the brain case and the gill arches is useful in understanding the basic changes in pressure that allowed for the eventual modification of the jaw and ear.
After infections, fish were killed and gill arches isolated into chilled phosphate-buffered saline (PBS) awaiting analysis of gill infection intensity using a stereomicroscope (Zeiss, SteREO Lumar .
Mouth and gill cavities, gill arches, tongue, and both jaws black; gill rakers pale.
We removed gill arches from six kokanee salmon infested with gill lice and preserved them in 70% ethanol for identification of the species of gill lice.