PHYSIOLOGY OF REPRODUCTION IN DOMESTIC FOWL. 1 57 



The oviduct ligaments were continuous to the posterior end of 

 the body cavity. That is the tube ended in the fold of enclosing 

 peritoneum while the fold continued to the posterior end of the 

 body cavity. The heavy bands of smooth muscle in the ventral 

 ligament (see E, Fig. 3) continued to the end of the body cavity 

 — several centimeters beyond the end of the tube. The tube 

 rounded off smoothly at the posterior end and the ligament 

 behind did not present the slightest indication that it had ever 

 contained any oviduct tissue. It seems probable that the duct 

 had never extended any farther than at present. From the 

 embryonic history of the oviduct it is evident that if the actively 

 growing point of a duct should cease at an unusually long distance 

 anterior to the cloaca a blind oviduct of this form might result. 



The development of the oviduct according to the account given 

 by Lillie (1908) begins on the fourth day of incubation as a groove- 

 like invagination of a strip of thickened peritoneum on the surface 

 of the Wolffian body or embryonic kidney. The lips of this 

 groove fuse on the fifth day so as to form a short tube open an- 

 teriorly to the body cavity and ending blindly posteriorly. The 

 open end of this tube becomes the ostium tuhcE abdominale or 

 funnermouth of the oviduct. The posterior end grows backward 

 between the strip of thickened peritoneum and the Wolffian 

 body. It normally reaches the cloaca on the seventh day. The 

 growing point is always a short solid wedge of cells. The duct 

 receives its lumen a short distance anterior to this. On the 

 twelfth day of incubation the primordium of the shell gland is 

 distinctly visible as an expansion of the lower end of this tube. 



The most probable explanation of the abnormality of the 

 oviduct found in the case described is that in early embryonic 

 development (probably on the sixth or seventh day of incubation) 

 the backward growth of the primordial oviduct stopped per- 

 manently while the differentiation of the part already formed 

 continued in the normal manner. 



As in other cases where the passage of the egg is prevented 

 the sex organs passed through their normal reproductive cycles; 

 the oviduct functioned as far as the point where the passage was 

 interrupted ; the eggs were then returned to the body cavity and 

 resorbed. The number of eggs and empty egg membranes found 



