Figure 4From: The ultrastructure of book lung development in the bark scorpion Centruroides gracilis (Scorpiones: Buthidae)Book lung precursor cells (C) not yet aligned anterior to the atrium. Centruroides gracilis, embryo. TEM. The cells have irregular shape and many small particles, possibly ribosomes and granules. Primordial air sacs, hemolymph channels and apical-basal polarity are not yet evident among these cells. N, nucleus. Scale, 2 μm.Back to article page