Oxygen consumption of normal and dwarf embryos ofXenopus laevis.

1. The oxygen consumption of normal and half-embryos ofXenopus laevis was measured by the automatic electromagnetic diver respirometer. 2. The rate of morphogenetic development of dorsal, left, and right half-embryos was found to be the same as in whole embryos but, in conformity with earlier observations, the development of ventral half-embryos is blocked. 3. Respiration of dorsal, right, and left half-embryos was found to be approximately half the normal, except in the initial cleavage period. Respiration of the ventral half-embryos, on on the contrary, failed to increase substantially by the time of gastrulation. 4. Our findings suggest a strict correlation between oxygen (and energy) consumption and epigenetic work.