54 THE WAY LIFE BEGINS 



ovaries of the rabbit, are but three-fourths of an inch in 

 length and are attached to the body wall, behind and lower 

 down than the kidneys. (See Figure 3.) The ovaries con- 

 tain many eggs, only a few of which are used in the lifetime 

 of the animal. 



The second structures are the oviducts, leading, as in all 

 other forms studied, from the ovaries to the vent. Instead, 

 however, of being merely a straight tube through which the 

 egg passes, as in the fish or frog, the oviduct now has three 

 well-marked portions or divisions, the fallopian tube, the 

 uterus and the vagina. (Figure 3.) In the rabbit, the paired 

 tubes enlarge and join in their lower course to form the uterus 

 or the place where the young are carried. The uterus, in turn, 

 leads into the vagina or vestibule and then to the outside. 

 In all of the lower forms that have been studied, the oviduct 

 and rectum or alimentary canal join and have but one opening 

 to the outside. The oviduct of the higher animals, however, 

 has its own outlet. It is into this duct that the male intro- 

 duces the sperm by means of a special organ, the penis. 



The reproductive organs of the male mammal, while they 

 seem to be unlike the female, correspond part for part. Here, 

 too, there are but two paired structures, the testes, or sperm- 

 producing glands, and the long tubes or spermatic cords 

 through which the sperm passes. The penis of mammals 

 and of man is simply a prolongation of the tube protected 

 by folds built up from the margins of the duct where it emerges 

 from the body. This organ conveys the sperms with more 

 certainty into the oviduct of the female. Male birds have 

 developed these folds to a considerable extent, the duck and 

 goose family having gone the farthest in this direction. The 

 penis because it is the most conspicuous of the visible repro- 

 ductive organs is apt to receive undue attention. From the 

 biological point of view it is an interesting evolutionary 

 structure, and one that has developed independently in other 

 forms than the mammal and for the same purpose; but, on 

 the whole, the organ is of relatively small importance as com- 

 pared with other parts of the reproductive apparatus since 

 fertilization does take place in some animals without it. It 



