Аннотация:The problem of the evolution of a cavity formed at the initial moment of time in the centralpart of a spherical cellular aggregate is solved. The earlier-developed model of a biological mediumformed by cells displaying mechanical activity and an extracellular fluid is used in studying the influenceof different mechanisms of active intercellular interactions (chaotic and directed nonlocal) on thepropagation of a front separating the cellular medium and the fluid. Numerical solutions show that incertain cases characterized by the fluid pressure and the density of the initial cell distribution the chaoticalactivity of the cells alone is sufficient for increasing the radius of the internal cavity. In othercases, the cavity development is impossible without the participation of the nonlocal mechanism ofactive interactions between the cells and the outer boundary. In the absence of the interaction betweenthe cells and the outer boundary the nonlocal mechanism of active intercellular interactions does notlead to the cavity growth for any its initial dimensions. The formulation and solution of the problemdescribe more completely the possible scenarios of the morhogenesis at one of the earlier stages of theembryonic development.