10 the flow apertures 32 b may be provided for equilibrating cell media disposed into the vessel 10 so as to distribute the cell media between the various support layers of the vessel 10 as defined by the bottom 12 and the shelves 20 although it is preferred to utilize a two aperture arrangement for each of the shelves 20 a single aperture 32 may be provided for each of the shelves 20 which may perform both functions of gas transmission and equilibration further more than two apertures 32 may be utilized for one or both of the functions of gas transmission and equilibration it is preferred that the gas transmission aperture 32 a and the flow aperture 32 b of a respective shelf 20 be spaced apart the top 14 has a generally inverted tray shape with a base 34 and a wall 36 which extends downwardly therefrom to at least partially bound the base 34 preferably the tubular neck 16 is formed integrally with the top 14 so as to extend therefrom alternatively an opening may be formed in the top 14 with the tubular neck 16 being formed as a separate component which is secured to the top 14 using any known technique such as fusion or adhesive it is further possible to form an opening which extends from the top.