348 



NATURE S TEACHINGS. 



the " eye " is placed over the button, while in the latter the 

 clasp or hook is passed through the eye. Several examples 

 of the Button and the Clasp are given on the right hand of 

 the illustration, and are too familiar to need description. 



As to the corresponding articles in Nature, they are very 

 numerous. We will take, for example, the Saddle-back or 

 Crow Oyster of our own shores. It is a most remarkable 

 being. It deposits upon the object to which it adheres a sort 

 of button of shelly matter, and the lower valve, which is nearly 

 flat, has in it an aperture which is placed over the knob, just 



-WING-HOOKS OF INSECT. 

 SADDLE-BACK OYSTEE. 



CLASPS AND BUTTON. 



as a button-hole goes over the button. As this arrangement 

 is confined to the lower valve, and cannot be seen unless the 

 upper valve be removed, the lower valve only is shown in the 

 illustration, as it appears when fastened to the side of a large 

 limpet. 



Of the Hooks and Eyes in Nature I have only taken two 

 examples, though there are many others. 



We all know the Bees, Wasps, Hornets, and other similar 

 insects, and that they possess four wings. I may here mention 

 that no insect which does not possess four transparent wings 

 is capable of stinging. 



When the insect is at rest the four wings may be easily 

 distinguished, but when it is in flight they coalesce, so that 

 practically the insect has two wings instead of four. This 

 object is attained in the following way : — 



