282 N. M. Stevens. 



one oviduct, as observed at 10:00 a. m. At 10:10 the egg a was 

 wholly within the oviduct, at 10:15 c was in, and 11:00 all five 

 were in, and a had moved down to x. Two eggs in the other 

 ovary were still partly outside of the oviduct. In every case 

 observed each egg made its way through its own opening into 

 the oviduct, forcing apart the sperm-duct and the anterior wall 

 of the oviduct. Fig. B is a sketch showing a ripe egg at the 

 anterior end of an ovary, observed at 11:30 a. m., forcing an 

 entrance into an otherwise wholly closed oviduct. The sperm- 

 duct (s), containing live spermatozoa lies above the ripe ovum (o) 

 and the younger oocytes. 



In some cases a number of eggs — as many as nine — were 

 crowded into one oviduct, occupying its whole length; in others 

 a single egg was seen to pass down the whole length of the oviduct 

 alone. In the latter case the egg was often drawn out in sausage 

 shape so that it extended half the length of the ovary or more. 

 One especially favorable egg was watched from 4:00 p. m. until it 

 was extruded at 5:25 p. m. When first observed, it appeared as 

 in Fig. Qa. Sketches were made at intervals of about 45 seconds, 

 and though there was constant change in the form of the egg, the 

 changes showed a regular rhythm, running from a through h 

 and various intermediate forms to c, in from 2\ to 3 minutes, and 

 then repeating the series of form changes. With each a-phase 

 the egg made a slight advance down the oviduct. There was no 

 visible muscular movement of the body corresponding to the vari- 

 ous form changes observed in the egg. In Fig. C a an air (?) 

 space is shown in the oviduct at each end of the egg. Such a 

 space is always observable in the case of a single egg in the ovi- 

 duct, in both living specimens and in sections. The first muscular 

 movement observed occurred when the advance air-bubble reached 

 the reproductive pore. The pore suddenly opened wide, the air- 

 bubble, covered by a thin film, passed out and broke, and the egg 

 followed, the opening closing behind it (Fig. D a and 6). Both 

 opening and closing had the appearance of a reflex. When several 

 eggs were passing, crowded together, down the oviduct, the pore 

 was only partly closed and then opened wide for another egg. 

 Several times the sphincter closed too soon and cut an egg in two. 



