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Profile drawings of the dural veins showing principal stages in their development in human embryos from 4 mm. to birth. It is of particular interest to notice their adaptation to the growth and changes in the form of the central nervous system. Fig. 481, 4 mm.; Fig. 482, 14 mm.; Fig. 483, 18 mm.; Fig. 484, 21 mm.; Fig. 485, 35 mm.; Fig. 486, 50 mm. crown-rump length; Fig. 487, 80 mm. crown-rump length; Fig. 488, adult. (After Streeter.)