Third pharyngeal pouch -dorsal portion: differentiates into inferior parathyroid gland ventral part: cells differentiates and form two cell cords fuse with each other behind the thorax to give rise to the promordium of the thymus 舌 甲状腺原基 下甲状旁腺原基 上甲状旁腺原基③ Third pharyngeal pouch: ---dorsal portion: differentiates into inferior parathyroid gland ---ventral part: cells differentiates and form two cell cords, fuse with each other behind the thorax to give rise to the promordium of the thymus