Fig. 11. SEM views of notochord cell protrusions. (A,B). Cross-sectional views of mid-stage II (A) and early stage III (B) embryos. Arrows indicate individual protrusions. Bright spots are yolk granules lying just under the membrane. (C) Outer (basal) surface of an early stage III embryo. In most (see arrows) but not all (arrowheads) cases, cells extend long continuous protrusions across the surfaces of adjacent neighbors. (D) Ventral surface of a late stage I embryo. Adjacent cells extend short interlocking protrusions across one another’s surfaces. Arrowheads outline a single cell, indicating in each case the direction of the protrusion. Scale bars, 10 µm in A and B and 5µm in C and D. Dorsal is up in A and B.
