110 



GENERAL ANATOMY. 



first describe this stage, and then follow the development of the female and 

 male organs respectively. 



As stated above, the anal depression at an early period is formed by an in- 

 volution of the external epithelium apart from the intestine, which is still 



A 



C 1 



Development of the external genital organs. Lulifferent type, I. II. III. Female. A B. At the middle 

 of the fifth month. C. At the beginning of the sixth. Male. A'. At the beginning of the fourth month. 

 B'. At the middle of the fourth month. C'. At the end of the fourth month. 1. Cloaca. 2. Genital tu, 

 bercle. 3. Qlans penis or clitoridis. 4. Genital furrow. 5. External genitnl folds (labia majora or scrotum). 

 6. Umbilical cord. 7. Anus. 8. Caudal extremity and ooccygeal tubercle. 9. Labia minora. 10. Uro- 

 genitul sinus. II. Frtonum clitoridis. 12. Preputium penis or clitoridis. 13. Opening of the urethra. 14. 

 Opening of the vngina. 15. Hymen. 16. Scrotal rai>hu. 



closed at its lower end. When the septum between the two opens, which is 

 about the fourth week, the urachus in front and the intestine behind both com- 

 municate with the cloaca. About the second month a transverse division (the 



