This duct receives the secretion of the whole anterior end of the kidneys[34], that is to say, of all the anterior segmental tubes.
(3) The secondary duct (fig. 4, d.) belonging to the lower portion of the kidneys opening into the former duct near its termination.
(4) The segmental tubes (fig. 4, st) from whose convolutions and outgrowths the kidney is formed. They may be divided into two parts, according to the duct by which their secretion is carried off.
In the male the following parts are present:
(1) The Müllerian duct (fig. 5, md.), consisting of a small remnant, attached to the liver, which represents the foremost end of the oviduct of the female.
(2) The Wolffian duct (fig. 5, wd), which precisely corresponds to the Wolffian duct of the female, except that, in addition to functioning as the duct of the anterior part of the kidneys, it also serves to carry away the semen. In the female it is straight, but has in the adult male a very tortuous course (vide fig. 5).
Fig. 5. Diagram of the arrangement of the Urinogenital Organs in an adult male selachian.
md. rudiment of Müllerian duct; wd. Wolffian duct, which also serves as vas deferens; st. segmental tubes. The ends of three of those which in the female open into the body-cavity, have in the male united with the testicular follicles, and serve to carry away the products of the testis; d. duct of the posterior segmental tubes; t. testis.
(3) the duct (fig. 5, d.) of the posterior portion of the kidneys, which has the same relations as in the female.