168 EVOLUTION AND DISEASE. 
firmatory result; my own experience as to their 
frequency coincides with the above statement. As a 
rule only one extra nipple is found, but occasionally 
two may be detected. A typical specimen is given in fig. 
89: the nipples are situated exactly in the line of the 
deep epigastric arteries. 
As accessory glands, or nipples, are so frequent in the 
human subject, it occurred to me that they ought 
f/f 
Fic. 89.—Two supernumerary nipplesin a Man. (After Lichtenstern.) 
theoretically to occur in quadrumana. To this end I 
examined systematically all monkeys coming under my 
observation, and in a short time secured two well-marked 
examples. The first was a female macaque (JZacacus 
sinicus) (fig. 90). On the left side, about an inch below 
the normal gland, an accessory and well-formed nipple 
was detected ; in size it equalled the normal teats, and 
was associated with glandular tissue and traversed by 
ducts. The second monkey came to hand a few months 
