444 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1920. 



There are two other species of fiddlers that are well known to 

 scientists although they are rarely differentiated by other observers. 

 One of these is Uca pugnax. Whereas pugilator prefers to make its 

 home in the sand, pugnax is essentially a mud lover. It frequents 

 muddy estuaries along the sounds of the coast and dwells among the 

 roots of the sedges far out on the marshes. This species is probably 

 as abundant as the sand fiddler, but it is less often seen. U . pugnax 

 may well be called the marsh fiddler. There is no easy or definite 

 way of distinguishing them from the other fiddlers. They are gen- 

 erally somewhat smaller than sand fiddlers, and, in accordance with 

 the dark background of their abode, they are darker in color. Their 

 upper parts are generally dark olive green, which shades off into the 

 soiled yellow color of the under parts and legs. Sometimes the 

 upper parts are dark blue instead of green. 



A third species of fiddler is known as Uca rrvinax. This form is 

 not so abundant as the other two and is generally found in rather 

 remote localities. It is often found at the borders of pools out on 

 the dunes, where the water is brackish or nearly fresh and at times 

 will dig its burrows in the sides of ditches 2 or 3 miles from salt 

 water. Brackish-water fiddler, although an awkward name, seems 

 to be the most appropriate one for this species. Again, the differ- 

 ences between it and the other species are relative only. It is larger 

 than either the sand fiddler or the marsh fiddler. In color it re- 

 sembles the former rather closely though it often has much more 

 red in its markings. 



HABITS OF THE SAND FIDDLER. 



As has already been noted the three species of fiddlers are so 

 closely similar to each other in structure that they are differentiated 

 by relative differences only. As would be expected, the developing 

 young of the species are equally difficult to distinguish and a descrip- 

 tion of one may well serve for all three. The habits and develop- 

 ment of U. pugilator, the sand fiddler, only will be referred to in 

 the following description. 



Instead of the bellicose appellation, pugilator, which scientists 

 have bestowed upon them, the common name, "sand fiddler," is 

 much more appropriate to the little crabs. They are quite wary and 

 are comparatively harmless even when cornered. Only the males 

 possess the large claw, which has given rise to both scientific and 

 common names for the species. This claw, which is almost as long 

 as the span of the walking legs from tip to tip, is generally carried 

 held in front of the body somewhat in a position of a fiddle, which 

 it also resembles in shape. When one of the males is caught he may 

 use the large claw for pinching, but the crab is so small that the 

 pinch is comparatively ineffectual. It will draw blood from only 



