Drosophila, head & antennae, left and right. Showing aristapedia, or the mutation of antennae (aristae) into leg-like structures. Dated by Wallace 1938, with initials CBB (Calvin B. Bridges). On drawing: 6B. Aristapedia, ss a-B male C.B.B. 3 [circled] 58.5.
The dome is 135′ in diameter and approximately the same distance from the ground to the top. The lower part is stationary, with concrete exterior walls 30′ high. The dome revolves.