564 ANATOMY IN A NUTSHELL. 



pectoral, ventral or abdominal, and inguinal. Sometimes they are quite high 

 on the sides of the animal but are never dorsal. The mamma of the cow is 

 situated in the median line, being formed from the coalescence of as many 

 mammae as there arc teats. These glands are paired as arule and common to 

 both sexes, but remain rudimentary and functionless in the male as a general 

 thing. The male mammas have been known to secrete milk. 



The mammary gland of the human female is situated between the third 

 and sixth rib on each side between the sternum and the axilla. The nipple 

 is situated between the fourth and fifth rib about four and one-half inches from 

 the middle line of the sternum ; but. of course, this position varies . The base of 

 each nipple is surrounded by a zone of colored skin called the areola, and this 

 areola has numerous small whittish tubercles which contain the openings of 

 the sebaceous glands. The nipple is highly vascular and its skin is sensitive 

 and contains retiform tissue and unstriped muscular fibers. There are about 

 twenty orifices in the summit of the nipple which are the ends of the milk ducts. 

 This gland is racemose and consists of from fifteen to twenty lobes, which are 

 independent of one another. Each of these lobes is made up of lobules, and 

 these are formed by the aggregation of alveoli in which the milk is secreted. 



Blood Supply. — The anterior intercostals, the external mammary (long 

 thoracic), and acromio-thoracic arteries. 



Nerve Supply. — Anterior and lateral cutaneous branches of the inter- 

 costal nerves. 



Lymphatics of the mammary gland pass into the axillary nodes. 



The Wolffian body is the mesonephros or primitive kidney, the excretory 

 organ of the embryo. It consists of a long tube in the lower part of the body- 

 cavity, running parallel with the spinal axis and joined at right angles by a 

 row of twisting tubes given off from the Malpighian body, and forming a struc- 

 ture resembling a comet. The Wolffian body develops into the head of the 

 epididymis, vas deferens, and ejaculatory duct in the male. 



LESSON CXCVI 



The Male Organs of Generation. (Plates CCLXXIV-CCLXXV-CCLXXVI- 



CCLXXVII-CCLXXVIII). 



The prostate gland is shaped like a chestnut and is about one and one-half 

 inches in itsl ransverse diameter while it is one and one-fourth inches from base 

 to apex. Its weight is aboul the same as the testicle, (six drachms). The 

 \i'i.\ of this gland is a1 the triagular ligament, [ts base is at the neck of the 

 bladder. Its posterior surface is joined to the rectum by areolar tissue. It 

 - dense firm capsule which is derived from the recto-vesical fascia and the 

 posterior layer of the trangular ligament. It consists of a median lobe and two 



lateral lobes. It is c posed of glandular matter, and muscular fibers which 



encircle the urethra. 



