spiracle defined in 1951 year

spiracle - spiracle;
spiracle - (1) Dorsally situated reduced first (most anterior) gill-slit in many fish. Its small size results from the connection formed between mandibular and hyoid arches for firm attachment of jaws; between these arches the spiracle lies. See also: Visceral Arch, Hyostylw Jaw Suspension. In most living bony fish, spiracle is closed up. The gill-pouch of embryo tetrapods representing spiracle develops into cavity of middle ear and Eustachian tube. (2) Of insects, synonym of stigma; external opening of trachea.

near spiracle in Knolik

letter "S"
start from "SP"
spiral cleavage

definition of word "spiracle" was readed 1047 times

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