64 MB. T. E. GUNN ON THE 



make any reference even to remains of the right ovary being 

 found on dissection, much less to a perfect functional organ, 

 though they may allude to the persistence of portions of the 

 Mlillerian duct on that side. 



Balfour * writes : — " In birds the left ovary alone is found in the 

 adult, and is attached by the mesovarium to the dorsal wall 

 of the abdominal cavity on the left side of the vertebral 

 column." 



Milnes Marshall f : — " In the embryo fowl there are two ovaries, 

 but in the course of development the right ovary disappears 

 and in the adult hen the left ovary is alone present. Of the 

 two oviducts the right one is rudimentary ; the left one, which 

 alone is functional, forms in the adult hen a wide convoluted 

 tube." 



And again t '■ — " In the female, or hen bird (of the fowl) 



the Mlillerian duct of the lught side, like the ovary, 

 disappeai's, though ti'aces of it may persist in the adult — the 

 left Mlillerian duct becomes the oviduct." 



Wiedei'sheim § : — " In Sau7'02}sida, as in other vertebrates, the 

 form of the gonads is influenced by that of the body ; thus 

 in Ohelonians they are broad, while in the snake and snake- 

 like lizards they are more elongated and, as well as in other 

 lizards, are asymmetrical, the organ of one side lying more or 

 less in front of that of the other. 



" More room is thus obtained for the development of the 

 ovaries, and in cases where the eggs are very large the organs 

 of one side tend to disappear as in certain elasmobranchs. 

 In birds, for instance, the left ovary only is completely 

 developed and functional. . . . 



" In birds the right oviduct as well as the right ovary 

 becomes more or less completely degenei-ated." 



Lillie li : — "The oi'gans of reproduction of the hen are the ovary 

 and oviduct of the left side of the body. Although the 

 right ovary and oviduct ai-e formed in the embiyo at the 

 same time as those on the left side, they degenerate more 

 or less completely in the course of development so that only 

 fvmctionless rudiments remain. 



" This would appear to be correlated with the large size of 

 egg and the delicate nature of the shell, as there is not 

 room for the eggs side by side in the lower part of the 

 body-cavity." 



Alex. Macalister *\ : — " There are two fasciculate ovaria, of which 



* ' Elements of Embryology,' p. 11. Foster and Balfour, 1883. 



t ' Vertebrate Embryology,' pp. 228-229. Milnes Marshall, 1893. 



t Ibid. p. 320. 



§ ' Comparative Anatomy of Vertebrates,' p. 474. Wiedershcim (adapted by Prof. 

 W. N. Parker, 1907). 



II ' Development of the Chick,' p. 21. Lillie, 1908. 



^ ' An Introduction to the Systematic Zoology and Morphology of Vertebrate 

 Animals,' (organs of reproduction in Birds) pp. 159-160. Alex. Macalister, 1878. 



