The Frog 87 



make their way into the coiled oviduct through a small opening, passing 

 down into the thin- walled distensible uterus ( ). 



The oviducts themselves are not directly connected with the ovaries, 

 but lie coiled next to the kidneys, the anterior end being a funnel-shaped 

 opening. The tube itself passes caudad beside the kidney to open 

 into the cloaca. The uterus is the rather large thin-walled chamber at 

 its termination, in which the eggs are stored after passing through the 

 oviducts until the final ^gg laying. The oviducts themselves, like the 

 ovaries, vary in size at different seasons of the year. 



The gelatinous substance covering the eggs is secreted by little 

 glands in the oviducts, called nidamental glands (Lat. nidus=a nest). 

 It is to be observed that the sexual organs and kidneys lie close together 

 and have a common opening, and in the male the same duct, namely, 

 the ureter, serves for an exit of both sperm and urine. A similar close 

 relation is found in nearly all other vertebrates, and when the study of 

 embryology is taken up it will be found that the ducts and kidneys were 

 originally derived from the same. region of the embryo. It is, therefore, 

 common to speak of the excretory and reproductive system together as 

 the urogenital system. 



THE FAT BODIES 



Directly in front of the gonads, we find a yellow organ with many 

 finger-like processes known as a fat body. It has a broader and closer 

 attachment to the anterior end of the male gonad than it has to the 

 female ovary. It is supposed to serve as a storehouse of nutriment, for 

 it varies in size and shape at different seasons of the year. Nearly all 

 the fat disappears from the cells in spring while as soon as the feeding 

 period begins the fat increases. 



References : 



Ecker, "The Anatomy of the Frog." 

 Holmes, "The Frog." 



Parker & Haswell, "Textbook of Zoology." 

 Bourne, "Comparative Anatomy of Animals." 

 Borradaile, "Manual of Zoology." 

 Schaefer, "The Endocrine Organs." 

 Bandler, "The Endocrines." 



