HPC activity from axolotl spleen and liver. (A) Representative view (×10) of spleen CFU at 10 days. (B) Magnification (×40) of a large CFU-E colony. (C) Magnification (×40) of a non-CFU-E colony. (D) Quantitation of CFUs in the liver and spleen reveals that the spleen contains more than twice as many CFUs as the liver (12 253 vs 5825, P = .0009; N = 3). Graphs show mean ± standard error of the mean of ≥3 independent experiments. (E) The proportion of CFU-E to other CFU colonies (P = .4). CFU assays were imaged on a Leica DMIRB inverted microscope using a SPOT Flex digital camera.