THE GENITAL ORGANS OF THE FEMALE. 991 



3. Muscles of the vulva. — Imperfectly described and determined in books on 

 Veterinary Anatomy, these belong to the category of voluntary muscles. We 

 recognize two, which will be described as the posterior and anterior constrictors. 



Posterior Constrictor of the Vulva. — AnalogouL to the constrictor 

 vagince of Woman, this muscle — included in the labia of the vulva — forms a veri- 

 table sphincter. Above, its fibres are mixed with those of the sphincter ani, and 

 are attached to the sacrum through the medium of the suspensory ligaments. 

 Inferiorly, the most anterior are fixed to the base of the clitoris ; the middle 

 are prolonged between the thighs, and are inserted into the inner surface of 

 the skin. 



Inwardly, it is in relation with the vestibular bulb and the mucous membrane 

 of the vulva. Its external face is separated from the skin of the labia by a very 

 vascular cellulo-fibrous tissue capable of tonic contraction, and in the midst 

 of which are always found isolated red fasciculi — dependencies of the principal 

 muscle. 



This muscle, in contracting during copulation, constricts the aperture of the 

 vagina and compresses the penis ; and as, in consequence of its attachment to 

 the clitoris, it cannot act without raising that erectile body, it appHes this to 

 the male organ and causes a greater degree of excitement. With animals in 

 <Estrum, the movements of the clitoris are frequently observed to propel that 

 organ outwards, especially after micturition ; in this case, the fibres of the 

 constrictor attached to the clitoris erect it by its base, while those which are 

 fixed into the skin between the thighs depress the inferior commissure of the 

 vulva. This double action necessarily exposes the erectile tubercle lodged in 

 that commissure. 



Anterior Constrictor of the Vulva. — This muscle is formed of arciform 

 fibres which envelop — below and laterally — the vaginal walls at the entrance of 

 the canal ; its extremities are continued, by means of aponeurotic fascia, to the 

 sides of the rectum, where they are lost ; some even pass tc the inferior surface 

 of the sacrum. By its posterior border, this muscle is mixed with the preceding. 



4. Muscular ligaments of the vulva. — Traces of the suspensory ligaments of 

 the male penis, these are disposed in the same manner at their origin. After 

 becoming united beneath the rectum, they descend in several fasciculi into the 

 labia of the vulva, and disappear among the fibres of the posterior constrictor. 



5. External skin. — This is fine and black (or hght-coloured), destitute of 

 hair, smooth and unctuous, and adheres closely to the subjacent tissues. 



6. The Mamm^. 



The mammce are glandular organs ; they secrete the fluid that should nourish 

 the young animal during the early months of its life. They are rudimentary in 

 youth, and become developed with the advent of puberty, assuming their greatest 

 development towards the end of gestation ; they are most active after parturi- 

 tion, and cease their function, as well as diminish in volume, when the period of 

 lactation has terminated. 



Situation. — These glands are two in number, placed beside each other in the 

 inguinal region, where they occupy the situation of the scrotum in the male. 



Form. — They are two hemispherical masses, separated from each other by a 

 shallow furrow, and showing in their centre a prolongation called the teat, nipple, 

 or mammilla, which is pierced at its free extremity by several orifices for the 



