THE HABITS OF FIDDLER-CRABS. 127 



movement by the writer frightened these lovers and they both 

 ran into the female's hole. This was the only time that a male 

 and a female were seen to enter the same burrow. On another 

 occasion a female pursued by a male entered her burrow. Her 

 suitor went halfway in after her, paused a moment as if feeling 

 something within the hole, and then went away. The female 

 came out of the hole and resumed her feeding. Another male 

 was seen pursuing a female twice his size. In both the latter 

 instances the male faced toward the female and approached her 

 "head on" or sideways without any dancing; the females kept 

 their backs toward the males. Still another case was observed 

 in which a male danced actively about a female keeping his back 

 constantly toward her; she was as unconcerned as possible and 

 continued to feed through the whole performance. 



The writer was interested to note that all males that were 

 dancing about females kept their backs continually toward them. 

 In such a position the bright coloration on the male's large chela 

 was almost if not wholly invisible to the female. Furthermore, 

 although many females are dull colored, the brightest tints are 

 found on this sex; and though the chelse of many males are 

 brightly colored, the greatest range of striking reds, purples, 

 blues, greens, and whites (as seen by the human eye) are found 

 on the backs and legs of the females. All these facts throw 

 doubt on the conclusions of Alcock ('92) who says (p. 416) : 



I have been able to observe that, whatever other functions the great 

 chela may serve — whether as a stopper to the mouth of the burrow, or as 

 a nuptial support, as some have supposed — it also, in the species under 

 consideration, is (1) a club used in the contests of rival males, and (2) a 

 signal to charm and allure the females. This last function is particularly 

 apparent. As one walks across the mud one first becomes aware of the 

 presence of these crabs by noticing that the surface of the mud is every- 

 where alive with twinkling objects of a pearly pink colour. Carefully 

 watched, these prove to be the enormous chels of a crowd of males of 

 Gelasimus, waving in the air, each little crab standing at the mouth of its 

 burrow and ceaselessly brandishing its big claw. On closer observation, 

 among every ten or so males a small clawless female may be seen feeding 

 in apparent unconcern. If the female should approach the burrow of a male, 

 the latter displays the greatest excitement, raising itself on its hindmost 

 legs, dancing and stamping and frantically waving its beautifully coloured 

 claw. From prolonged watching I feel convinced that the waving of the 

 claw by the male is a signal of entreaty to the female, and I think no one 

 can doubt that the claw of the male has become conspicuous and beautiful 

 in order to attract the female. 



Alcock's observation could not have been very detailed for he 

 "did not actually see the rival males seize each other in the 

 conflict," and he could scarcely have failed to do this if any 



