Mechanical and cellular aspects of gastrulation in the sea urchin Lytechinus variegatus.
D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology; D005775:Gastrula / Q000502:physiology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D012617:Sea Urchins / Q000196:embryology*