422 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



PLAY. 



Some of the activities of fiddlers are like those displayed by higher 

 animals Avhile at play. Crabs frequently dart about without a 

 serious purpose, and are sometimes downright mischievous. On 

 one occasion a male was half-heartedly pursuing a female. She went 

 to her burrow, secured a plug nearby, and shut herself in. The 

 male then came directly to the burrow, seized the plug, and cast it 

 to one side. The female was just emerging from her burrow when 

 the writer ended the episode by frightening the participants by a 

 sudden movement. Another time two males of medium size were 

 seen running about for perhaps half an hour over an area about 12 

 meters in diameter. They kept close together and acted like two 

 mischievous sailors ashore. The tide was coming in rapidly, and in 

 their rambles the pair came to a place where a large, slow-moving 

 crab was carrying a plug to close his burrow. The pair waited 

 until the plug had been pulled down, then one of them went to the 

 hole and removed it; as the outraged owner emerged they scuttled 

 away. To all appearances activities like those just described were 

 carried out in a spirit of " sport." 



MATING. 



During the mating season a fiddler-crab colony is an interesting 

 place. If a female walks across the mud every male stands at the 

 mouth of his hole and waves his big claw frantically up and down, 

 often accentuating such movements by squatting and stretching with 

 his walking legs. (Fig. 8.) If a female approaches he makes every 

 effort to induce her to enter his burrow, frequently dancing or pos- 

 turing before her. 



A courtship will be described, which was observed at North Fal- 

 mouth, Mass., July 11, 1912. The male waved, and at 12.17 p. m. 

 the object of his attention approached and went part way into his 

 burrow. He rushed up and tried to push her in, but she resisted. 

 He then retired 3 inches and stood motionless for three minutes with 

 his claw outstretched in front, then sneaked up and again tried to 

 push his prospective mate into the burrow. She again resisted, he 

 retired, and both were quiet for two minutes. The male then ap- 

 proached cautiously and stood motionless with upraised chela close 

 to the female for three and a half minutes ; then he again attempted 

 to push her down, but without success. He then raised his claw and 

 standing high on his legs assumed a statuesque pose which he held for 

 10 minutes (I took his picture, fig. 9). The female, meanwhile, fed 

 a little, moved away a couple of inches, then went part way down 

 the hole. When the male again approached, she dodged, but came 



