Testis (100X) Image copyright: University of Oslo, CC BY-NC-ND 4.0. (Tissue stain: H+E). Magnify Labels Up (40X) The circular structures with a lumen in the middle are seminiferous tubules. Magnify to se individual cells. Published May 19th 2019, updated July 2nd 2020. Share on Facebook Tweet Send email Testis Testis