Histological specimens of chick embryonic gizzard at day 9 to day 18 of incubation. (200× magnification).

<p>Collagen bands and trellis-like muscle bundle confirmed at 11 day of incubation enlarges in subsequent days. <i>Key</i>: <i>C</i>: collagen band, <i>M</i>: myoblast, <i>R</i>: red blood cell, <i>S</i>: smooth muscle.