24 Hour Chick Embryo

proamnion Anterior neuropore

Neural fold somites

Undifferentiated somites Hensen’s node Primitive streak

Sphlancnic mesoderm Anterior  intestinal portal

foregut

Subcephalic pocket

Anterior  neuropore

pharynx Oral plate

Subcephalic pocket ectoderm mesoderm endoderm

Head fold Pharyngeal pouches

Anterior intestinal portal

Almost neural tube notochord Head mesenchyme Amniocardiac vesicle

Sphlanchnopleure Sphlanchnopleure (?) ( ?)

Neural groove

somites

coelom

Intermediate mesoderm Lateral plate mesoderm

Cardiac primordia midgut

Somatic and sphlancnic mesoderm

Area opaca vasculosa

Mesenchymal cells Primtive pit

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