Plate VIII of "A Descriptive Catalog of the Monstrosities in the Cabinet of the Boston Society for Medical Improvement". Figure 18: cranium of an acephalus fetus; A) the posterior portion of the occipital bone; B) the frontal and C) the parietal bones. Figure 19: cranium of a monstrosity. Figure 20: cranium of a monstrous calf. Figure 21: base of the skull, with a portion of the skeleton of a double fetus.