SAGITTAL • DICTIONARY ONE.COM • Definition of Sagittal

... segmentation-cells, that, for instance, the first segmentation furrow separated off the material and potencies for the right half of the embryo from those for the left half. He had tried to show experimentally that the first furrow in the frog's egg coincided with the sagittal plane of the embryo,[491] and his later success in obtaining a half-embryo from one of the first two blastomeres seemed to ...

— Form and Function - A Contribution to the History of Animal Morphology • E. S. (Edward Stuart) Russell