364 



(XJMPARATIVE ANATOMY 



Fertilisation is internal in all Elasmobranchs except Lsemargus, in which 

 generative ducts are said to be wanting. 



Fig. 289. 



Ficjs. 289 and 290. — Female and JIale Ue,inogei<ital Okgaxs of Eaja hath, x j. 

 (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 (Mtillerian duct); fl.t', common opening 

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

 mii.d, mesonephric (Wolffian) duct ; od.g, oviducal gland ; ((•■■.■, oesophagus; 

 ov, right ovary (the left is removed) ; ^re.(?, remains of anterior part of 

 Mtillerian 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; iig.p, urinogenital papilla; ug.s., urinogenital sinus; n.p, urinary 

 papilla ; i(r, kidney ducts ; ur', opening of kidney duct into the lU'ino- 

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

 is removed) ; i(t', its opening into the cloaca ; r.d, vas deferens ; r.s, 

 vesicula .seniinalis ; c.s', its opening into the sperm-sac. 



In female Holocephali tlie 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- 



