REPRODUCTIVE ORGANS 783 



if not a difficult matter. 1 The ripe eggs are received by the 

 Oviducts, which 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 with the 

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

 peritoneal elastic lamella? 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, twisting and 

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

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

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

 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 " vagina " 

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

 inches in length) opening into the dorsal wall of the urodaeum 

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



Microscopically examined, the structure of the parts above 

 mentioned is seen to be as follows The whole 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 vagina, but scanty or 

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

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

 the infundibulum is thin and contains numerous cells with cilia, 

 the vibrating motion of which propels the ovum downward. In 

 the other portions of the duct the mucous membrane forms from 

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

 glands. 



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

 hypertrophic turgescence. In the common Fowl at the period of 

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



1 This is so often the 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, which 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. 



