482 MANUAL OF ZOOLOGY sect. 



The left ovary (ov) is a large organ in the adult bird, its 

 surface studded with follicles or ovisacs, varying in size 

 from about 15 mm. in diameter downwards, and each 

 containing a single ovum. The left oviduct (/. od) is 

 long and convoluted ; its anterior end is enlarged to form 

 a wide, inembranous ccelomic funnel (/. od") into which the 



adr 



cl$ 



Fig 292. — Columba livia Ma'e 

 urinogenital organs, adr, ad- 

 renal; cl. 2, urodamm; cl. J, 

 proctodeum; k, kidney; ts, 

 testis, that of the right side dis- 

 placed; Mr, ureter; nr' , aper- 

 ture of ureter; vd, vas deferens; 

 Td\ its cloacal aperture; v. s, 

 vesicula seminalis. ( From Par- 

 ker's Zootomy.) 



Fie. 293. —Columba livia. Female urino- 

 genital organs, cl. s, urodaeum; cl. ?, 

 proctodeum; k, kidney; l. od, left ovi- 

 duct; I. od' , its cloacal aperture; I. od" , 

 its ccelomic funnel; /. od'", its ccelomic 

 aperture; oi\ ovary: r. od, right oviduct; 

 r.od', its cloacal aperture; ur, ureter; 

 7ir' , its cloacal aperture. (From Parker's 

 Zootomy.) 



ripe ova pass on their liberation from the ovisacs ; the rest 

 of the tube has thick, muscular walls, lined with glandular 

 epithelium, and opens into the urodaeum. 



Internal impregnation takes place. As the ova or 



