280
L . G A L L I E N
FIG. 13. Interruption of spermatogenesis in a haploid Pleurodeles placed in parabiosis,
and having attained adulthood. Condition at 3 years of age. A, General view of testis;
absence of spermatozoa in the central cysts where spermatogenesis has ceased. B, Division of primary spermatocytes with atypical mitoses (below) and pyknosis (at right). C,
In one cyst completion of degeneration of cells. (After Gallien.)