_Gonads._--The portion of coelomic lining which gives rise to the reproductive cells retains its primitive relations most nearly in the female, where, as a rule, the genital cells are still shed into the splanchnocoele. Only in Teleostomes (_Lepidosteus_ and most Teleosts) the modification occurs that the ovary is shut off from the splanchnocoele as a closed cavity continuous with its duct. In a few Teleosts (_Salmonidae_, _Muraenidae_, _Cobitis_) the ovary is not a closed sac, its eggs being shed into the coelom as in other groups. The appearance of the ovary naturally varies greatly with the character of the eggs. The portion of coelomic lining which gives rise to the male genital cells (testis) is in nearly, if not quite, all cases, shut off from the splanchnocoele. The testes are commonly elongated in form. In Dipneusti[20] (_Lepidosiren_ and _Protopterus_) the hinder portion of the elongated testis has lost its sperm-producing function, though the spermatozoa produced in the anterior portion have to traverse it in order to reach the kidney. In _Polypterus_[21] the testis is continued backwards as a "testis ridge," which appears to correspond with the posterior vesicular region of the testis in _Lepidosiren_ and _Protopterus_. Here also the spermatozoa pass back through the cavities of the testis ridge to reach the kidney duct. In the young Teleost[22] the rudiment of the duct forms a backward continuation of the testis containing a network of cavities and opening as a rule posteriorly into the kidney duct. It is difficult to avoid the conclusion that the testis duct of the Teleost is for the most part the equivalent morphologically of the posterior vesicular region of the testis of _Polypterus_ and the Dipneusti. _Relations of Renal and Reproductive Organs._ (1) _Female._--In the Selachians and Dipnoans the oviduct is of the type (Müllerian duct) present in the higher vertebrates and apparently representing a split-off portion of the archinephric duct. At its anterior end is a wide funnel-like coelomic opening. Its walls are glandular and secrete accessory coverings for the eggs. In the great majority of Teleosts and in _Lepidosteus_ the oviduct possesses no coelomic funnel, its walls being in structural continuity with the wall of the ovary. In most of the more primitive Teleostomes (Crossopterygians, sturgeons, _Amia_) the oviduct has at its front end an open coelomic funnel, and it is difficult to find adequate reason for refusing to regard such oviducts as true Müllerian ducts. On this interpretation the condition characteristic of Teleosts would be due to the lips of the oviduct becoming fused with the ovarian wall, and the duct itself would be a Müllerian duct as elsewhere. [Illustration: From _Arch. zool, expérimentale_, by permission of Schleicher Frères. FIG. 11.--Urino-Genital Organs of the right side in a male _Scyllium_. (After Borcea.)