vacuole (vak'u-61)

A small air cell or a globular space containing either air or a pellucid liquid. Auerbach's v. An 8-shaped, transparent v. formed at the center of the vitellus, according to Auerbach's theory of segmentation, after the disappearance of the original nucleus and as a step preliminary to the formation of the nuclei of the two succeeding segmentation spheres. See aster, amphiaster, and tetraster. contractile v. A v. observed in a structurele ma of protoplasm (as in the Endoplastic a) which slowly fills with a watery fluid and, after reaching a certain size, contracts to obliteration, the proce of distention and contraction being repeated rhythmically, after the manner of a systole and diastole, food v's. 1. Of Lankester, large v's in the endoderm cells of one of the Medusae (Limnocodium). They have been found to contain an albuminous substance supposed to be the product of intracellular digestion. 2. See gastric v. gastric v. A v. formed in the protoplasm of certain protozoa around a particle of food surrounded with water, nuclear v. See Auerbach's v. pulsating v. See contractile v. [Lat., vacuolum, from vacuum, empty.]