EXTRAIT: Origine des pouss~es ovocytaires chez Tilapia mossambica. L'ovaire de TiIapia mossambica a ~t~ ~tudi~ dans le but de pr~ciser l'origine des pouss~es ovocytaires. Apr~s la ponte l'ovaire n'est pas vide pour autant, et il y subsiste des ovocytes ~t tousles stades du d~veloppement. Les replis de l'~pith~Iium germinatif et les tractus ~pith~liaux ramifies contiennent des flots de cellules qui produisent des ovogonies primaires, lesquelles se transforment en ovocytes et en cellules folliculaires. I1 ne semble pas qu'une nouvelle pouss4e ovocytaire puisse se faire ~ partir des r4sidus des follicules des ovocytes atr~tiques. Seuls les ovules m6rs non ~vacu~s par la ponte subissent une atr~sle et se rdsorbent; les ovocytes immatures ou en vole de croissance ne d~g~n~rent pas. L'asynchronisme de T. mossambica se traduir par la pr& sence simultan~e, dans l'ovaire, d'ovocytes ~ tousles stades de croissance et de maturation.

Channa striala fry (100 20 mg) and fingerlings (2 & 0.2 g) were offered mosquito larvae as prey and the adults (75 _+ 5 g) small fishes. The size of the fish was directly related to satiation time and inversely related to satiation amount. The influence of satiation levels on handling time, showed an increase to almost eight-fold in fry and fingerlings and about two-fold in adults. The study also revealed the role played by the young of C. striala in mosquito control. With the increase in size of the fish the preference for mosquito larvae was seen to decrease. The air breathing habit and hence its ability to survive in polluted and oxygen-depleted waters makes it a suitable candidate as a fish for mosquito control.

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The formation of the micropyle in Tilapia mossambica and Stigmatogobius javanicus, two fresh water teleosts is described. In T. mossambica the micropyle is formed by a single modified follicular cell, while in S. javanicus it is formed by a cellular mass derived from the follicle.

The satiation amount of food and satiation time of three size groups of fish were studied and were found to vary with variations in prey density. The reasons for this variation are discussed. Bindoo Mathen, C.M. Aravindan geszczenie ryb stanowi1cych pokarm Channa striata (Bloch), zmniejsza si,; wowczas Hose pokarmu potrzebne• go dla zaspokojenia ich glodu, bez wzgl,;du na dlugosc drapieznika. Czas potrzebny do nasycenia gl:odu wzrasta wraz ze zwi,;kszeniem liczebnosci ofiar we wszystkich grupach dlugosci drapieinika. Tzw. ,,efekt nadmiaru", spowodowany przez duz1 liczb,; ofiar jest przyczyn!J zmniejszonej presji drapieznikow na ryby, co sprawia, ie zmniejsza si,; ilosc pokarmu a wydluza sie czas nasycenia przy wyzszych liczebnosciach ofiar.