Maybe blood vessels that are part of the clitoris? Clitoris is not just one little knob on the vulva but a rather pronounced organ that has erections in tissue that stretches deeper into the pelvis, very alike the male erective tissues (clitoris and penis have a lot in common and evolve from the same cell cluster in embryo).

Even parts of modern medicine is struggling with the reality of the “erecting” clitoris (as they do with a lot of female medicine). In that aspect this drawing would be rather modern and sort of accurate.