Lobules of Parotid of a Sheep
In mammalia, each salivary gland first appears as a simple canal with bud-like processes, lying in a gelatinous nidus or blastema, and communicating with the cavity of the mouth. As the development of the gland advances, the canal becomes more and more ramified, increasing at the expense of the blastema in which it is still enclosed. the branches or salivary ducts constitute an independent system of closed tubes. Shown are lobules of the parotid, with salivary ducts, in the embryo of the sheep at a more advanced stage.