424 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



advance. Apparently he was attempting, as Chidester (1912) says, 

 to " demonstrate his maleness." In the Philippines crabs were often 

 seen standing motionless with outstretched claw for as much as 

 20 minutes. (Fig. 10.) Perhaps such individuals were looking 

 for a mate. 



Fig. 9. — Uca puoilator. Male in coukting attitude before a female. 

 Drawn by Ilattie Wakeman from a photograph taken at West Falmouth, Mass., 



July 11, 1912. 



Probably fiddlers copulate in the burrows of the males, but they 

 have never been seen to do so. Experiments have been conducted in 

 the laboratory, however, in which the mating activities were ob- 

 served. Jelly glasses were filled with clean water to a depth of about 

 an inch ; a male and female were then placed together in each. Sev- 



FiG. 10. — Uca forcii'ata staxuing at attention. 

 Drawn by Tom Jones from a photograph. 



eral copulations were observed under such conditions. In no case did 

 a male use his great chela in manipulating or holding the female, 

 and that organ was not used as a " nuptial couch," as some have sup- 

 posed it would be, A figure has been published elsewhere (Pearse, 

 1914), which shows the position assumed during copulation. 



