SKIN-SECRETIONS 29 



are merely the glands from which the secretion flows. 

 On the neck behind the eye these glands are larger 

 and the fluid from these parts is usually more acrid. 



A threatening attitude is a frequent means of 

 escape or defense among amphibians. Toads nor- 

 mally have the sections of the breast-bones overlap- 

 ping, so that they can swell themselves enormously 

 when angry. Frogs have their breast-bone pieces 

 meeting edge to edge, which prevents this power of 

 expansion. 



