The testes are located dorsally. Penguins do not have intromittent organs. There are varying reasons as to why intromittent would be evolutionarily advantageous in these species. The testes seem to demonstrate extensive morpholical changes throughout the year, the height of such size change during the breeding season. This increase in testis volume occured over the 8 stages of spermatogenesis.
Primary spermatocytes are present in an irregular row toward the lumen.
The lumen is filled with sytoplasm. There is a basal row of spermatogonia and Sertoli cells. Up to one-half the primary spermatocytes in a given tubule cross section are in the stage as synapis where chromatin is concentrated to one side of the nucleus. Towards the lumen two to three of primary spermatocytes are in synapsis. Stage 4 A row of secondary spermatocytes lies toward the lumina of tubules.