364 



COMPARATIVE ANATOMY 



Fertilisation is internal in all Elasmobraiichs except Lsemargus, in which 

 generative ducts are said to be wanting. 



FIG. 289. 



FIG. 290. 



FIGS. 289 and 290. FEMALE AND MALE URIXOGENITAL ORGANS or Raja batis. x ^. 

 (From T. J. Parker's Zootomy. ) 



a.p, abdominal pore ; d, cloaca ; epd, left epididymis (the right is removed) ; 

 fl.t, anterior portion of oviducts (Miillerian duct); fl.t', common opening 

 of the two oviducts into the ccelome ; i.r, internal body ; k, kidney ; 

 mn.d, mesonephric (Wolffian) duct ; od.g, oviducal gland ; oes, oesophagus; 

 ov, right ovary (the left is removed) ; pn.d, remains of anterior part of 

 Miillerian duct ; ., sperm sac ; s.s', its opening into the urinogenital 

 inus ; t, left testis (the right is removed) ; u.b, dilated end of mesonephric 

 duct; ug.p, urinogenital papilla; tig.*., urinogenital sinus; u.p, urinary 

 papilla ; ur, kidney ducts ; tir', opening of kidney duet into the urino- 

 genital sinus ; lit, uterine portion of left oviduct (that on the right side 

 is removed) ; nt', its opening into the cloaca ; r.d, vas deferens ; v.s, 

 vesicula seminalis ; t'.-s-', its opening into the sperm-sac. 



In female Holocephali the generative organs are essentially 

 similar to those of Elasmobranchs, but in the male they present 

 certain peculiarities. The unripe sperms pass into the immense 

 epididymis, in which they become ripe and invested by spermato- 



