Abstract: Laboratory apparatus for cloning mammalian cells includes a support plate and a plurality of tubular cylinders fixedly secured within the plate and projecting from one face thereof. All of the cylinders, with the exception of one pair, are disposed within a concentrated array defined within a predetermined sector region of the plate, the remaining pair of cylinders being located remote from the sector array yet equidistantly spaced from each other and from the sector array so as to complete the distribution pattern. A substantially C-shaped ring member is fixedly secured to, or integrally formed with, the opposite face of the support plate, in order to facilitate maneuverability of the assemblage when placing the same onto a Petri dish for isolating the colonies developing thereon. The plate and ring member are fabricated from transparent polycarbonate in order to permit the colonies to be identified or viewed by background lighting techniques.