Annual Changes in the Ovary of Xenentodon Cancila (Ham.)

The gonads of Xenentodon cancila show well marked changes in their morphological (shape, size and volume) and histological features during different months of the reproductive cycle. On the basis of these changes, the reproductive cycle is divided into spawning (May to September), postspawning (October to December) and prespawning periods (January to April). In the present study ten cytological stages in the development of oocytes have been observed in the ovary which are early and late chromatinnucleolus stages, early and late perinucleolus stages, early and late yolkvesicle stages, early and late yolk stages, prematuration stage and the mature stage. Besides these different oogenetic stages, Corpora atretica and postovulatory follicles are also present in the ovaries. The quantitative study of reproductive cycle of Xenentodon cancila has been made in respect of gonosomatic index during different months of the year. Although this study, regarding the gonosomatic index, is approximate, yet it is quite significant in understanding the gonadal cycle and seasonal changes in the gonads.