Symbols for designating multiple births

Efforts to improve existing symbols as used in genetic pedigree charts constitute progressive steps in the science of heredity. The recent article by Macklin1 in this JOURNAL is appreciated as a contribution to this objective. The present writer is in favor of the adoption of Dr. Macklin’s improved symbols for miscarriaees and stillbirths as well as of those designating cousin marriages and identical twins. It is unfortunate, however, that Dr. Macklin chose the “double bond” as representative of fraternal twins (Figure 3A). In the writer’s opinion fraternal twinning may be symbolized equally well and without confusing the proper use of the marriage line by merely doubling the fraternity line above and between the progeny symbols for the fraternal twins (Figure 35). Confusion of the marriage line in Figure 3A would be rare, it is true, but it is a possibility and as such it should be avoided. © 1945 Oxford University Press