merous assemblages of smaller mollusks, such as 

 Nassa, the mud snail, and Littorina, the peri- 

 winkle, are inevitably in evidence. 



Perennially present, also, but seen only when 

 the hummocks are free from frost and ice, is the 

 multitudinous fiddler crab, Uca pugilator, pugna- 

 cious in appearance, but not in fact. The holes of 

 these innumerable fiddlers perforate the surface 

 of the spongy dripping soil, and lead to the laby- 

 rinthine burrows which honeycomb the marsh — 

 countless tunnelled chambers which contribute 

 greatly to the softness of the porous and saturated 

 earth. If the stranger, who finds himself straying 

 into the stillness of this retreat, stands motionless 

 for a while, he is likely to be deceived by a barely 

 audible sustained rustling which he will at first 

 mistake for wind as it passes over the reeds: he 

 will soon note, however, if he is in the least ob- 

 servant, that the source of this sound is as strange 

 as is its unceasing tenor : it is the perpetual crawl- 

 ing of the crabs as they move about over the soggy 

 soil. Stealthily and cautiously they crawl, suspi- 

 cion marking the most minor movement, as they 

 go about sidewise carefully searching the ground 

 for the microscopic algal food which they scrape up 



[315] 



