Pearse—On the Habits of Uca Pugnax. 
795 
tivity. Many emerged from their burrows and moved down 
with the edge of the falling tide until the beach dried off; then 
they descended into their holes again and waited until it was 
time to plug them. They usually did not go far from home, 
but the females wandered about much more than the males. At 
North Falmouth the beach at low tide was alive with armies of 
fiddlers that were twenty or Thirty feet from their holes. Where 
the crabs were most abundant (optimum habitat) the burrows 
were about five inches deep; but above high tide mark many of 
them went down over two feet and there was water in the bot¬ 
tom. 
As has been stated, Uca pugnax bred earlier than U. pugila¬ 
tor. Egg bearing females of the first species were observed 
Fig. 4. Uca pugilator, closing his burrow by pulling down mud with bis 
walking legs. 
from July 4 to July 15. They wandered boldly about over the 
sand and could be picked out at once by the dark mass of eggs 
which caused the abdomen to hang down below the body. No 
females of Uca pugilator' were observed to be carrying eggs until 
the first part of August; the exact date was not noted. These 
two species of fiddlers present another case like that of Fow¬ 
ler’s toad and the American toad, which have different breeding 
seasons, though they commonly occur in the same locality and 
in the same habitats. The fact that Uca pugnax is darker 
colored than U. pugilator and usually lives in mud (which 
would absorb more heat than sand on account of its darker 
color, and would contain more organic material which would 
generate heat in decaying) may account for its earlier breeding 
period. It would be interesting to know whether other animals 
