During spring, testicular lobules showed all spermatogenic developmental stages (Figure 2) and continue the same structure during summer where testicular lobules were filled with spermatozoa also, showed thin tunica albuginea and interstitial connective tissue compared to (Figure 3).
The tunica albuginea of both testes and ovaries had no uniform thickness all over the year but, it reached a maximum thickness during winter and became thin during spring and summer due to pressure exerted on it by the distended testicular lobules or enlarged mature follicles, and began to increase again during autumn.
Our results revealed testicular lobules of variable shapes and sizes according to seasons, where it decreased in size during winter which was cold, rainy and short day light season (resting season) and thereafter increased during spring and reached a maximum size during summer which was hot, dry and long day light season (spawning season) as they were distended by different developmental stages of spermatogenic cells and they showed slight decrease again during autumn which was dry and less hot than spawning season (spent season) but still enlarged and larger as compared to structure during winter.
The transition from the outer to the central region of the testis is marked by an abrupt change in the configuration of the testicular lobules, which lose the germinal epithelium and become ducts where lobule function has shifted from sperm production to sperm storage (Fig.
The central ducts of the testis are continuous with the proliferative segment of the testicular lobules, which lose the germinal epithelium in the innermost region of the testis and function as sperm storage structures.
The earliest males to metamorphose had solid testicular lobules. Primary spermatogonia were recognized in the lobules of some animals (Figure 2).
The testicular lobules of sex-reversed males contained oocytes when observed histologically (Figure 5), and males that metamorphosed later contained large numbers of oocytes (Figures 6 and 7).
The poorly developed testicular lobules that lacked germ cells observed in males from the corn field in York County resembled gonadal dysgenesis observed in males exposed to 0.1 ppb atrazine in our laboratory study and effects described in X.