In _Teleosteans_ the generative organs are comparatively large. In some families the ovaries are without closed covering and without oviducts, as in _Salmonidæ_, _Galaxiidæ_, _Notopteridæ_, _Murænidæ_, and others. The surface of such an open ovary--as, for instance, that of the Salmon--is transversely plaited, the ova being developed in capsules in the stroma of the laminæ; after rupture of the capsules the mature ova drop into the abdominal cavity, and are expelled by the porus genitalis. The ovaries of the other Teleosteans are closed sacs, continued into oviducts. Frequently such ovaries coalesce into a single body, or one in which the division is effected internally only by a more or less complete septum. Fixed by a mesoarium, the ovaries occupy generally a position outwards of the intestine or air-bladder; their form varies as well as the thickness and firmness of their covering, which frequently is an extremely thin transparent membrane. The inner surface of the ovarian sac is transversely or longitudinally plaited or covered with fringes, on which the ova are developed, as in the open ovaries. In the viviparous Teleosteans the embryons are likewise developed within the ovary, notably in the _Embiotocidæ_, many _Blenniidæ_, and _Cyprinodontidæ_, _Sebastes viviparus_, etc. Among the Cyprinodonts the end of the oviduct is attached to the anterior anal rays, which are modified into supports of its termination. In _Rhodeus_ the oviduct is periodically prolonged into a long oviferous tube, by means of which the female deposits her ova into the shells of living Bivalves. [Illustration: Fig. 70.--Ditrema argenteum, with fully developed young, ready for expulsion by the genital orifice, _o_; _a_, folds of the ovarian sac; _v_, vent.]