236 



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.od'}, a considerable opening just external to that 

 of the left ureter : the rudimentary right oviduct has a 



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

 fro 01 the ventral aspect ; B, in longitudinal section (nat. size). 



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

 r/.i, anterior, cl.2, middle, and cl.?,, posterior, chamber of cloaca : od, 

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

 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, &/'), 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. 



