Testis of a mouse. The spermatogonese is the process by which male spermatogonia develop into mature spermatozoa. 'Zooming in' reveals many meiotic cell divisions, cells of sertoli, cells of Leydig and so on. Plastic section from Technovit 7100; Microtome: LKB 2218 Historange; Staining: Haematoxylin/eosin; Section 1µm.