REPRODUCTIVE ORGANS 783 



if not a difficult matter.^ The ripe eggs are received by the 

 Oviducts, Avhich furnish them with the " white albumen," the shell- 

 membrane and the shell, before expelling them into the CLOACA 

 (pp. 197, 198). In young birds both oviducts are almost equally 

 developed, but the right one soon becomes reduced to an insignifi- 

 cant ligamentous strand along the ventral side of part of the 

 Kidney. This one-sided suppression of the organs may possibly 

 be referable to the inconvenience that might be caused were each 

 oviduct to contain an egg ready to be deposited. Practically the 

 Oviduct is a gut-like tube suspended by its own mesentery and open- 

 ing by a wide slit-like infundibulum into the body-cavity near the 

 Ovary. This upper portion of the Oviduct, corresponding Avith the 

 Fallopian tube of human anatomy, has extremely thin Avails, while 

 peritoneal elastic lamellae attach it to the hinder margin of the left 

 Lung in such a way as to secure the reception of any ripe egg that 

 may burst from the Ovary. The next portion of the Oviduct is 

 much narrower with thick glandular walls, which, tAvisting and 

 turning irregularly, secrete the albumen, and it is connected by a 

 constricted portion, the isthmus (p. 197), Avith a dilated "uterus," 

 situated on the ventral and partly on the right side of the Eectum 

 and cloaca. The walls of the isthmus deposit the shell-membrane, 

 while those of the uterus secrete the calcareous shell and the pigment, 

 and the uterus leads into a rather glandless portion, the " A^agina " 

 (Avhich in a common Fowl is about an inch, and in a Goose two 

 inches in length) opening into the dorsal AA^all of the urodseum 

 (p. 90) to the left of the urethral papilla. 



Microscopically examined, the structure of the parts above 

 mentioned is seen to be as folloAvs — The AA^hole duct consists of four 

 layers: (1) an outer peritoneal, mesenteric lamella; (2) a layer of 

 smooth unstriped muscular and, for the most part, longitudinal 

 fibres, most numerous in the uterus and the A^agina, but scanty or 

 absent in the infundibulum; (3) connective tissue Avith blood- 

 vessels ; and (4) the tunica mucosa, mucous membrane, Avhich in 

 the infundibulum is thin and contains numerous cells Avith cilia, 

 the vibrating motion of Avhich propels the ovum doAvnAvard. In 

 the other portions of the duct the mucous membrane forms from 

 ten to tAventy or even more folds, and contains numerous secreting 

 glands. 



During the breeding-season the Avhole Oviduct is in a state of 

 hypertrophic turgescence. In the common FoavI at the period of 

 rest it will be only some six or seven inches long and scarcely a 



^ This is so often tlie case that the usual notes on the labels which collectors 

 attach to their specimens are at that season mostly the expression of fancy. The 

 vicinity of the suprarenal capsules, Avhich are of a pale yellow colour and 

 "granular" in appearance, makes them liable to be mistaken for ovaries, or 

 more often for the testes when in a dormant and much reduced condition. 



