200 



BIOLOGY 



the frog is ready to discharge them at the time of copulation. 

 These sacs are called seminal vesicles. Some species of frogs 

 do not have such vesicles. 



In the females the ovaries are situated in a position cor- 

 responding to that of the spermaries in the male; Fig. 100 ov. 



During the late spring ,and 

 summer they are rather small, 

 slightly folded, leaf-like or- 

 gans, not much larger than 

 the spermaries, though differ- 

 ing in shape. In the fall of 

 the year the eggs in these 

 ovaries begin to grow, causing 

 the ovaries to become greatly 

 expanded. During the fall the 

 ovaries are usually greatly 

 swollen and completely fill 

 the abdominal cavity, almost 

 concealing the other organs. 

 The oviducts that carry the 

 eggs to the exterior are not 

 directly connected with the 

 ovaries. They are very much 

 coiled tubes, o, lying beside the 

 kidneys, each ending at its an- 

 terior end in a funnel-shaped 

 opening. From this opening 

 the tube passes backward 

 beside the kidneys, and, after 

 making many coils, finally 

 opens into the cloacal chamber at the back. Just before its 

 termination it is swollen into a rather large, thin-walled cham- 

 ber, the uterus, ut, in which the eggs may be stored for a time 

 after passing through the oviducts before the final egg laying. 

 These long ducts vary greatly in size at different seasons, 



FIG. 100. REPRODUCTIVE ORGANS 



OF A FEMALE FROG, ATTACHED TO 

 THE KIDNEYS 



ki, kidneys; ut, uterus; 



o, oviduct; c, cloacal 



ov, ovary filled with eggs; chamber. 



