*'''Bursa of Fabricius''' - site of haematopoesis in birds and necessary for the maturation of B-cells. The bursa develops as a dorsal diverticulum of the proctadael region of the cloaca (lat. ''bursa fabricii'') | *'''Bursa of Fabricius''' - site of haematopoesis in birds and necessary for the maturation of B-cells. The bursa develops as a dorsal diverticulum of the proctadael region of the cloaca (lat. ''bursa fabricii'') |