These testes have been incised longitudinally to expose the testicular parenchyma (TP) and the mediastinum (M).  Arrows denote direction of flow of spermatozoa and fluids toward the efferent ducts and the head of the epididymis.

EH  = Epididymal Head       
PP = Pampiniform Plexus
ET = Epididymal Tail       
TP = Testicular Parenchyma
M = Mediastinum