CHAPTER THREE 



Reproductive System or tne Adult Fro^: 

 Jxana pipiens 



The Male 



Secondary Sexual Characters 

 Primary Sexual Characters 

 The Testes 

 Spermatogenesis 

 Reproductive Behavior 

 Accessory Structures 



The Female 



Secondary Sexual Characters 



Primary Sexual Characters 

 The Ovaries 



The Body Cavity and the Oviducts 

 Oogenesis — Maturation of the Egg 



The Male 



Secondary Sexual Characters 



The mature male frog is generally smaller than the female, ranging 

 from 60 to 110 mm. in length from snout to anus. The identifying 

 features which distinguish it from the female are a darkened thumb 

 pad which changes thickness and color intensity as the breeding 

 season approaches; a distinct low, guttural croaking sound with the 

 accompanying swelling by air of the lateral vocal sacs located between 

 the tympanum and the forearm; a more slender and streamlined body 

 than that of the female; and the absence of coelomic cilia except in 

 the peritoneal funnels on the ventral face of the kidneys. Males of 

 many species carry additional features such as brilliant colors on the 

 ventral aspects of the legs {R. sylvatica), black chin {B. fowleri), or 

 the size and color of the tympanic membrane. 



Primary Sexual Characters 



The Testes. 



The testes of the frog are paired and internal organs and are sus- 

 pended to the dorsally placed kidneys by a double fold of peritoneum 

 known as the mesorchium. This mesentery surrounds each testis and is 

 continuous with the peritoneal epithelium which covers the ventral 

 face of each kidney and lines the entire body cavity. 



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