somites

Undifferentiated somites

Neural fold

Anterior neuropore

Hensen’s node

Primitive streak

proamnion

foregutAnterior intestinal portal

Sphlancnic mesoderm

Anterior neuropore

pharynx

Oral plate

Subcephalic pocket

Subcephalic pocket

ectoderm

mesoderm

endoderm

Head fold

Anterior intestinal portal

Pharyngeal pouches

Almost neural tube

notochord

Head mesenchyme

Amnio-cardiac vesicle

Sphlanchnopleure (?)

Neural groove

somites

Intermediate mesoderm

coelom

Lateral plate mesoderm

midgut

Cardiac primordia

Somatic and sphlancnic mesoderm

Primtive pit

Area opaca vasculosa

Mesenchymal cells

Yolk and blood islands

Yolk and blood islands in region of area opaca

Cardiac primordia

Cardiac primordia

Subcephalic pocket <?>

Somatic mesoderm

Sphlancnic mesoderm

mesoderm

Blood island and yolk