FETAL DEVELOPMENT 363 



mary glands begin. Sympathetic nerves. Nose discernible. 

 Additional centers of ossification. 



Ninth Week. Weight, three-fourths of an ounce. Length, 

 one and a quarter inches. Pericardium. Anal canal. External 

 genitals begin to indicate sex. Ovary and testis distinguishable. 

 Kidney characteristic. External ear indicated. 



Third Month. Weight, four ounces. Length, two and 

 three-quarter inches. Chorion frondosum. Placental vessels. 

 Tonsil. Stomach rotates. Vermiform appendix. Liver large. 

 Epiglottis. Ovaries descend. Testes in false pelvis. Hair 

 and nails. Development of different parts of brain. Limbs 

 have definite shape. 



Fourth Month. Weight, seven and three-quarter ounces. 

 Length, five inches. Head one-fourth of entire body. Germs 

 of permanent teeth. Distinction of external genitals well 

 marked. Spinal cord ends at end of coccyx. Eye-lids and 

 nostrils closed. 



Sixth Month. Weight, two pounds. Length, twelve inches. 

 Amnion at maximum size. Trypsin in pancreatic secretion. 

 Air vesicles. Eye-lashes. Lobule of ear characteristic. 



Seventh Month. Weight, three pounds. Length, fourteen 

 inches. Meconium. Ascending colon. Testes at internal 

 rings. Cerebral convolutions evident. Differentiation of mus- 

 cular tissue. 



Eighth Month. Weight, four to five pounds. Length, 

 sixteen inches. Body more plump. Ascending colon larger. 

 Testes in inguinal canal. Skin brighter color. Nails project 

 beyond finger tips. 



Ninth Month. Weight, six to seven pounds. Length, 

 twenty inches. Meconium dark green. Testes in scrotum. 

 Labia majora'in contact. Spinal cord ends at laSjtl lumbar 

 vertebra. Ossification centers completed. 



