THE MALE 



39 











- Spermatozoa in 

 Malpighion 

 corpuscle 



SpermotozoG 

 packed in unniferous 

 tubule 



Bowman's capsule \ Malpighian 

 Glomerulus \ corpuscle 



Spermatozoa 



Glomerulus 

 Bowman's capsule 



Vas efferens 

 full of sperm 



Kidney of the male frog during amplexus showing spermatozoa in the kidney 

 tubules and Malpighian corpuscles, en route to the uro-(mesonephric) -genital 

 (vasa efferentia) duct. 



time as they may be liberated through the genital tract to function in 

 fertilization. 



In observing a section of the summer testis of the frog under low 

 power magnification, it is readily apparent that each seminiferous 

 tubule may contain all the stages of maturation and that each stage 

 is found in a cluster or group within the tubule. Each group of 

 similar cells is derived presumably from a single original spermato- 

 gonium, by the processes of mitosis and meiosis. This is reminiscent 

 of the condition found in the grasshopper (Rhomaleum) testis. 

 Maturation of the germ cells occurs in groups so that when the 

 spermatid stage is reached, the tips of the metamorphosing spermato- 

 zoon heads are all gathered together into the cytoplasm of the Sertoli 

 cell. Spermatozoa may remain thus throughout the entire period of 

 hibernation only to be liberated under the influence of sex-stimulating 

 hormones during the early spring. These spermatozoa are functionally 



