xin 



PHYLUM CHORDATA 



299 



present. There was an extensive lateral-line system, leaving its 

 impress on the bones of the skull, in the Stegocephala. 



Urinogenital Organs. In the Urodela the kidneys (Fig. 966, 

 N) are much elongated and are divided into two portions, a broad 

 posterior part, the functional kidney (GN), and a narrow anterior 

 A B 



777 Q 



m/(Otl) 



FIG 



. 966. Diagrams of urinogenital organs of male (A) and female (B) ITrodele. a, collecting 

 tubes : <i\. sexual portion of kidney ; Ho, testis ; Ig. (t'r.) Wotflan duct (ureter) ; ma, IIK.I' , 

 vestigial Mullerian duct of male ; mg. (Od), oviduct ; X, non-sexual portion of kidney ; 

 On. ovary : IV. vast rtferentia ; f, longitudinal canal. (From Wiedersheim's Comparative 

 Anatomy, after Spengel.) 



sexual part connected in the male with the efferent ducts of 

 the. testis. Numerous ducts leave the kidney and open into the 

 Wolffian (mesonephric) duct [Ig. (Ur.)], which thus acts as a ureter 

 in the female, as a urinogenital duct in the male. The oviduct 

 [mg. (Od.)] is developed from the Mullerian duct, a rudiment of 

 which (mg., mg'.) occurs in the male. In the Gymnophiona the 

 kidneys extend the whole length of the coelome, and in the young 



