Uca. musica. Railib. 



Drawn by J. Caldwell from specimens obtained by Caldwell and Miss W. Diirani 

 at Balboa mud flats durini; llie summer of 1920. Tbis is the first record of a tiddler 

 crab in our region. The male is shown with the large claw. Sometimes the large 

 claw was on the right, sometimes on the left. Specimens brought to the laboratory in 

 moist sand made their burrows and lived all summer. In spite of the larger claws of 

 the males they gave way to the females when in each other's way. 



