520 



GENITAL ORGANS OF THE COW 



somewhat ellipsoidal in form, but flattened transversely. The base (or dorsal 

 surface) of each gland is slightly concave and slopes obliquely downward and for- 

 ward in adaptation to the abdominal wall, to which it is adherent; posteriorly it 

 is in relation to the large supramammary lymph glands and a quantity of fat. 

 The inner surface is flat, and is separated from the other gland b}^ a well-developed 

 double septum. The outer surface is convex. Four well-developed teats are 

 present; they average about three inches (ca. 7 to 8 cm.) in length. It is customary 



Fig. 416. — Cross-section of Mammary Glands of Cow. 

 a, Body of glarul; b, lactiferous .sinus; c, cavity of teat; d, duct of teat; e, intermammary groove; /, septum 



between glands; o, supramammary fat. 



to consider the udder to consist of four "quarters." There is no septum nor visible 

 division between the two quarters of the same side, but, on the other hand, in- 

 jections of fluids of different colors into the two teats of the gland demonstrate that 

 the cavities drained by them do not communicate. 



Tho size and form of the {ihuuls vary greatly; in the highly .speeialized dairy breeds (e. g., 

 Holsteins) they often attain enormous dimensions. The size of the udder is not a certain index 

 of its productivity, since some so-called "fleshy" udders contain a very large amount of inter- 

 stitial tissue and relatively little 7)arenchyma. Small accessory teats often occur posteriorly; 

 commonly these are rudimentary and imperforate (j)olythelia), hut .sometimes they drain a small 

 amount of gland substance (polymastia). Sanson described a case in which there were seven 

 teats, all giving milk. 



