122 ZOOLOGY. 



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union of the cells from the two individuals, or to provide 

 for the nourishment of the embryo during its development. 



T|je__gQna<Lin. A female is called the ovary, the reproduc- 

 tive cells it produces are called ova, and 'the gonoduct is an 

 oviduct. As conveniently corresponding terms in the male 

 we have spermary, spermatozoa, and spermiduct ; but the 

 spermary is more usually called the testis, and the spermi- 

 duct the vas deferens. We shall use the latter terms in our 

 description. 



The details as to the changes that take place in these 

 organs will be more conveniently taken in the section on 

 embryolog} 7 . Here we are concerned with the anatomical 

 facts merely. 



It is one of the peculiarities of vertebrates (not un- 

 known among invertebrates) that there is a close con- 

 nextion between the accessory reproductive organs and 

 the organs for nitrogenous (renal) excretion, and that this 

 connexion is usually closer in the male than in the female. 

 The reason for this connexion of two systems of utterly 

 different function cannot be understood from the study of 

 the rabbit alone : we only allude to it here in order that 

 the student may be on his guard against confusing the 

 organs of one system with those of the other. The two 

 systems are often referred to together as the Urino -genital 

 (or Urogenital) System, 



3. Female Reproductive Organs. In the female we 

 find the paired ovaries posterior and lateral to the kidneys 

 (fig. 64). Each oviduct is a tube, open at its anterior end 

 to the coelom, but this open end is an' expanded funnel, 

 and so near the ovary that there is every chance that an 

 ovum when set free from the ovary will fall into the oviduct, 

 especially as the funnel is set with ciliated epithelium which 

 maintains a current towards the tube. Nevertheless, this 

 imperfect arrangement for ensuring the passage of ova 

 towards the exterior is one of the most peculiar facts in the 

 anatomy of the higher vertebrates, especially as many less 

 highly organised animals have their ovaries united to the 

 oviduct, so that there is no risk of an ovum going wrong. 



The oviducts are divided into two parts an anterior 



