. Chordate morphology. Morphology (Animals); Chordata. - excretory part of kidney _vas deferens (nephric duct "ureter" nephric duct Mtjilerian duct. -Seminal vesicle opening of gut into cloaco MALE. urinary papilla FEMALE Figure 10-48. Urogenital systems of the shark. A, mole Squo/us; B, relationship of testicular ampullae and tubules in Scyllium con/cu/a; C, urinary system of female Scyllium; D, urogenital ducts and cloaca of female Squalus. (A and D after Marinelli and Strenger, 1959; B and C after van den Broek, 1933} ampullae to the urogenital sinus where they end blindly above t
. Chordate morphology. Morphology (Animals); Chordata. - excretory part of kidney _vas deferens (nephric duct "ureter" nephric duct Mtjilerian duct. -Seminal vesicle opening of gut into cloaco MALE. urinary papilla FEMALE Figure 10-48. Urogenital systems of the shark. A, mole Squo/us; B, relationship of testicular ampullae and tubules in Scyllium con/cu/a; C, urinary system of female Scyllium; D, urogenital ducts and cloaca of female Squalus. (A and D after Marinelli and Strenger, 1959; B and C after van den Broek, 1933} ampullae to the urogenital sinus where they end blindly above the urogenital gland. In the very young the urogenital gland is small; it is larger in the adult although it may be embedded in connective tissue and not apparent. The male has anterior and posterior pelvic claspers utilized in copula- tion (Figure 10-49). The female (Figure 9-25) is similar to the shark in the position of the ovary, the general nature of the oviduct, and the large, shelled eggs. The Miillerian ducts have a common midline ostium, below the esophagus, and each has an ex- panded nidamental gland area. Also there are regions identi- fied as the isthmus, uterus, and vagina. The oviducts open individually, lateral to the excretory pore in a shallow uro- genital sinus. Anterior to the excretory pore and behind the anal opening is an opening into a blind-ended sac which has been called the seminal receptacle. The young female is presumed to have a more marked urogenital sinus. The anterior wall of this sinus forms a forward-extending bladder or sac, the seminal receptacle. In the mature female, with the partial aversion of the uro- genital cavity, the sac comes to open anteriorly, while the Mijilerian ducts open lateral to the excretory pore (Figure 10-49). The small urogenital gland of the male may be the homolog of the seminal receptacle of the female. General observations Only the middle part of the genital ridge develops in sharks. The genital fold hangs down into
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