434 TEXT-BOOK OF EMBRYOLOGY. 



defects in the vagina may occur, however, when the uterus is normal. In rare 

 instances the hymen is absent; in other cases it closes the entrance to the vagina 

 a condition known as imperf orate hymen. 



Malformations of the uterus and vagina resulting from persistence of the 

 cloaca and atresia of the anus are mentioned on page 357. 



HERMAPHRODITISM. 



This condition implies a combination of the male and female sexual organs 

 in one individual, accompanied by a blending oi the general characteristics of 

 the two sexes When such an individual possesses both ovary and testicle, the 

 condition is known as true hermaphroditism; when the individual possesses 

 ovaries or testicles, the condition is known as false hermaphroditism. 



TRUE HERMAPHRODITISM. The presence of both ovary and testicle in one 

 individual is one of the rarest anomalies in man. Furthermore, one or both of 

 the organs are sexually immature. Three forms can be recognized (Klebs) : 



1. Lateral hermaphroditism, in which an ovary is present on one side and a 

 testicle on the other; 



2. Unilateral hermaphroditism, in which both ovary and testicle are present 

 on one side, either ovary or testicle, or neither, on the other side; 



3. Bilateral hermaphroditism, in which both ovary and testicle are present on 

 both sides. 



In all these cases the general character of the body is of an intermediate 

 type, sometimes tending toward the male, sometimes toward the female. The 

 external genitalia are also of an intermediate type, with hypospadias, small 

 penis, separate scrotal halves, and small vaginal orifice. The uterus usually 

 shows some degree of duplicity. 



FALSE HERMAPHRODITISM. In this type of hermaphroditism, in which 

 either ovaries or testicles are present in an individual with mixed general 

 sexual characteristics, two varieties can be recognized : 



1. Masculine false hermaphroditism, the more common, in which testicles are 

 present but the external genitalia and general character of the body approximate 

 the female; 



2. Feminine false hermaphroditism, in which ovaries are present but other- 

 wise male characteristics predominate. 



The causes underlying the origin of hermaphroditism are among the most 

 obscure in teratogenesis. It is well known that up to the fourth or fifth week 

 the anlagen of the sexual glands are histologically "indifferent," and later be- 

 come differentiated into ovaries or testicles (p. 405). Since the secondary 

 sexual characteristics are dependent upon the development of the primary, they 

 also are brought out later. If the " indifferent " glands give rise to both ovaries 



