FIELD BOOK OF PONDS AND STREAMS 



Asellus crawl over muddy bottoms eating dead leaves and 

 refuse in pools which appear very unpropitious for animal 

 life, where they are often the only animals to be found in 

 winter and very early spring. They are very light on their 

 seven pairs of feet. From above an Asellus looks like a 

 miniature armadillo, gray and heavy. Beginning in very 

 early spring and continuing through the summer they have 

 a new brood of young every 5 to 6 weeks and the females seem 

 to be always carrying a brood pouch full of eggs or of young 

 ones (Fig, 131). Length under one inch. 



Crayfishes or Decapods — Decapoda 



Except for the southern fresh water prawns, crayfishes are 

 the only fresh water representatives of this group made widely 

 known by the edible crabs and lobsters of the sea. Cray- 

 fishes with their five pairs of legs, the first pair armed with 

 conspicuous nippers, look and behave like smaller editions 

 of lobsters. They live in limy regions in quiet streams, 

 sometimes in rivers, hiding under stones or burrowing into 

 banksides. They lie in wait for fishes and water insects and 

 clutch and tear them to pieces with their big pincers ; they also 

 eat all sorts of dead plant and animal matter. Some species, 

 Camharus diogenes and limosus, mate in the fall but do not 

 lay their eggs till spring, but the more common crayfish, 

 Camharus bartoni, mates and spawns the year round. An 

 interesting account of crayfish breeding habits is given in the 

 Ajnerican Naturalist, 1904, by E. A. Andrews, who kept them 

 (Cambarus limosus) in aquaria the year round. Before laying, 

 the female hid in a dark corner of the aquarium and assumed 

 a peculiar tripod-like position with her body held high, 

 propped up by her tail and outspread claws. Standing thus 

 poised she patiently cleaned her swimmerets and abdomen, 

 scraping with the points and combs of her other feet until the 

 swimmerets and abdomen were as clean as if the shell had 

 just been shed. Finally she turned over on her back, and lay 



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