an assembly and components therefor are disclosed for use in the field of cell and tissue culture . the assembly includes a base having one or more wells , and a cell culture insert which is mountable to the base such that the bottom wall of the insert is suspended within the well . each well has a generally rectangular configuration such that openings are provided at each corner of the well for introducing fluid to the well . a cover is provided for protecting the assembly and maintaining the position of the cell culture insert .