THE REPRODUCTIVE SYSTEM 



145 



anchoring nipples are unassociated with milk secretory 

 glands, but among the Marsupial animals the unusual 

 circumstances of pouch life have led to the develop- 

 ment of a peculiar type of nipple, which is both an 

 anchoring and a milk-conveying nipple. Now, when the 

 mother Lemur (or Bat) is at rest, the young one reverses 



FIG. 55. THE PECTORAL MAMMARY GLAND OF A TYPICAL BAT 

 (Brachyphylla cavernarum). 



its position, and clinging with its legs round its mother's 

 waist and grasping the fur of her chest with its hands, 

 takes into its mouth one of a pair of pectoral nipples, 

 and from this it suckles (see Figs. 55 and 56). The 

 pectoral nipples are associated with pectoral mammary 

 glands, and are the source of supply of infantile nutrition. 

 The aberrant Galeopithecus volans probably combines the 

 functions of milk secretion and of anchoring in its pectoral 

 mammary glands (see Fig. 57). Now in the Primates 

 higher than the Lemurs the inguinal anchoring nipples are 



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