TKE HABITS OF PIDDLER-CEABS. 125 



There was a marked difference between the different species in 

 regard to their relative pugnacity. Uca a7inulipes was the most 

 active and excitable; U. forcipata was the most sluggish, though 

 an excellent fighter when aroused. The fights between males 

 and females were usually of short duration, and as a general 

 thing were occasioned by one coming too near the burrow of 

 the other. When the intruder was chased away the affair ended. 

 In the combats between females, the contestants sometimes faced 

 each other, but they usually stretched to their full height and 

 danced about excitedly back to back and struck out behind with 

 their walking legs. 



Some of the activities of the fiddlers were like those displayed 

 by higher animals while at play. The crabs frequently darted 

 about apparently without a serious purpose, and were some- 

 times downright mischievous. On one occasion a male was 

 half-heartedly pursuing a female. She went to her burrow, 

 secured a plug near by, 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 the burrow when the 

 writer ended the episode by frightening the participants by a 

 sudden movement. Another time, two males (an Uca marionis 

 nitida and an U. forcipata) 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 mis- 

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

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

 moving U. forcipata was carrying a plug to close his burrow. 

 They waited until the plug had been pulled down over the ovraer, 

 then the U. forcipata went to the hole and removed it; and, as 

 the outraged owner emerged, the plug-remover and his mate 

 scuttled off toward the former's burrow some 4.5 meters away. 

 He soon closed his own burrow, for the advancing water threat- 

 ened to inundate it, and his companion hurried away down the 

 estero. The writer watched him until he had gone more than 

 11 meters and was lost to view at the edge of the advancing water. 

 To all appearances activities such as these just described were 

 carried out in a spirit of sport. 



Alcock ('00) believed that the males were "greatly in excess 

 of the females," but this difference may have been assumed from 

 only a casual observation. Some instances were noted by the 

 writer in which the females outnumbered the males. For 

 example, the counts shown in Table III represent the total 



