The thymus was collected from day old to nine months of age at monthly interval. Histomorphologically, the thymus gland in guinea fowl consists of cortex and medulla. Cortex was composed of small and medium sized lymphocytes, myoid cells and few Hassall’s corpuscles located in the meshwork of reticular cells. The medulla consisted of less densely packed medium and large sized lymphocytes with relatively more reticular cells and Hassall’s corpuscles. The reticuloepithelial cells were large cells with long cytoplasmic process located in both the region. Myoid cells were frequently found in the medulla and in the corticomedullary region, occasionally found in the cortex. |