embryonic shield

The bulge is the first external expression of the embryonic shield.

The embryonic shield extends above the equator.

The germ ring is wide, approaching 1 mm; and the embryonic shield is broader still.

The embryonic shield is long, intruding anteriad on the evacuation zone, which has a jumble of floor cells.

The subgerminal cavity, distinct from the evacuation zone, begins to inflate under the embryonic shield, but little outside it.

The germ ring is narrow now and the embryonic shield is longer, nearly reaching to the evacuation zone above the equator.

The embryonic shield has the same function as the dorsal lip of the blastopore and acts as the organizer.

The blastoderm can be cleanly separated (by dissection) from the ysl surface beneath the germ ring and embryonic shield, but the deep yolky cells at the animal pole adhere to the ysl.

It activates the expression of Squint (a Nodal related signaling protein aka ndr1) and Bozozok (a homeodomain transcription factor similar to Siamois) which act together to activate goosecoid in the embryonic shield.

The trans-Atlantic bickering covers a palette of seemingly unconnected matters, ranging from terrorism to protectionist impulses on both sides of the Atlantic to suggestions that the United States might effectively scrap the 1972 Antiballistic Missile Treaty and move to deploy an embryonic shield against Soviet warheads.