214 ZOOLOGICAL GLEANINGS 



of the ''hand" of the larger cheliped a transverse row 

 or key-board of fine teeth, which, when the cheliped 

 is flexed, can be made to play against a ridge or 

 another row of teeth on its ''arm" or ischiopodite, 

 much as a man might rub one side of his chest with the 

 palm of the corresponding hand. The whole mechanism, 

 except that it is on a larger scale and has a more finished 

 appearance, is very much like that by means of which 

 crickets and grasshoppers produce their shrill music, 

 and no one has ever doubted that it is used for the 

 same purpose, although it seems that very few people 

 have actually heard it in action. I myself watched 

 Ocypoda macrocera for three seasons without ever 

 learning that it made any sounds such as this large 

 and efficient-looking musical apparatus seems capable of 

 producing, and I was beginning to think that the 

 structure must, after all, have some quite other function, 

 when one morning, while coast-lining with Lieutenant 

 Huddleston on the sandy wastes of the Godavari delta, 

 I at last, like Ancient Pistol, heard with ears that which 

 I had so long been waiting for. That is to say, I heard 

 a noise very much like that which an angry squirrel 

 makes, and discovered that it came from a red ocypode 

 crab into whose burrow another individual had tres- 

 passed. 



In order to understand the matter, it should be 

 known that these crabs, although they do not seem 

 to have any social co-operation, are gregarious, and 



