Structure of the testis in neonate and adult harp seals, Pagophilus groenlandicus.

The structure of the seminiferous tubules in neonate harp seals, Pagophilus groenlandicus, was essentially similar in one-, five- and ten-day old animals. The tubules were small in diameter, devoid of lumina and contained predominantly supportive cells. The interstitial cells in the neonates were large, numerous and highly vacuolated. They became smaller and appeared less active in the ten-day old animals compared with the one-day old seals, although they were still considerably more numerous and vacuolated than in testes taken from adult harp seals.