2 3 6 



ZOOTOMY. 



231. In the male the genital papillae (Fig. 52, v.d'] 

 conical elevations just external to the urinary apertures : on 

 their apices are the apertures of the vasa deferentia. 



232. In the female the aperture of the left oviduct 

 (Fig. 53, l.odf\ a considerable opening just external to that 

 of the left ureter : the rudimentary right oviduct has a 



ur.lf cl? 



FIG. 55. Columba livia. The cloaca of a young female. A, opened 

 from the ventral aspect ; B, in longitudinal section (nat. size). 



If./, bursa Fabricii : b.f, its opening into posterior chamber of cloaca : 

 <r/.i, anterior, cl.2, middle, and ct.^, posterior, chamber of cloaca : orf, 

 opening of oviducts into middle chamber of cloaca : r, rectum : ur, 

 opening of ureters into middle chamber of cloaca. 



small opening (r.od') similarly situated on the right side : 

 in the young bird the two apertures are of equal size 

 (Fig. 55, od). 



233. The aperture of the bursa Fabricii (Fig. 55, b.f), a small, 

 crescentic opening in the middle of the dorsal wall of the posterior 

 chamber : by drawing the cloaca, backwards, and gradually dissecting it 

 away from its attachments, the bursa is seen as an ovoid, somewhat 

 flattened sac (b.f}, with glandular walls, situated between the dorsal 

 wall of the cloaca and the roof of the pelvic cavity : it is best de- 

 veloped in young individuals, when it may attain a length of a quarter 

 to three-quarters of an inch ; in the adult it is usually absent. 



