Bufonidse 



with great vigour, the air from the side slits in the mouth presses 

 on the side walls of the throat-pouch with such force as to make 

 the pouch look as if it were made up of two sacs, i. e. the wall at the 

 midline is not as forcibly distended as are the side walls. 



If we hold a toad in our hands, we realize certain details of his 

 appearance which we should not have noticed if we had looked at 

 him at longer range. 



The two oval black nostrils are very conspicuous. Each is 

 situated on a line between the inner corner of the eye and the end 

 of the muzzle, and is somewhat nearer the former. There may be 

 rhythmic movements of the membrane bordering the openings 

 which show that air is being taken in. 



The throat also moves rhythmically in and out as if in breath- 

 ing, but more rapidly than the nostril membranes. Timing the 

 movement of the throat, we find that the pulsations occur at the 

 rate of about three per second.^ The movement is confined to the 

 floor of the mouth and throat, and is, in truth, a swallowing act, 

 necessary to force the air down into the lungs. The necessity 

 arises from the facts that the nasal tubes leading from the external 

 nostrils open into the front part of the mouth (see Fig. 279), in- 

 stead of far back in the throat, as they do in higher forms, and 

 that the toad has no ribs, and so cannot have chest movements to 

 suck the air into the lungs. 



The elevated eyes are very brilliant and very beautiful.^ 

 The pupil is a black horizontal oval and is surrounded by a broad 

 rim (iris) of gold. While we watch, the eyes are shut, both to- 

 gether or one at a time. The process seems mainly one of making 

 the eye level with the surrounding surface by lowering it into the 



^The rate varies with temperature and other conditions. It is much slower when the toad is 

 sleeping or hibernating. The throat movements may cease altogether for a minute or more at a 

 time. This occurs when the toad is eating or is " playing dead." 



2 The toad's eye is so beautiful that it gave rise in past ages to the fable of the " jewel " of 

 the toad's head. This jewel was supposed to be a precious stone found within the toad's head. It 

 acted when worn as a tahsman protecting the wearer from all sorts of evil. 



Possibly the supposed venomous quahties of the toad gave the toad-stone special value, for the 

 old tlieory that " like cures Hke" was fully believed, and all sorts of poisonous plants and animals 

 were used as charms and taUsmans. 



The jewel in the toad's head is referred to again and again in Uterature and history. 



" The fayrer the stone is in the toad's head, the more pestilent the poyson in his bowelles." 

 —Lyly. 



" There may be many that ware these stones in Ringes beeing verily persvraded that they 

 keep them from all manner of grypings and pains of the belly." — Topsell. 



76 



