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fathoms. As in many deep-water species the eyestalks are rudimentary. The five 

 posterior pairs of thoracic limbs are chelate in both sexes, and the first pair of 

 antennae have their inner branches long, while the carapace is flattish with a small 

 rostrum. 



The remaining three families, namely, the Nephropsidce, or lobsters, the 

 PotamobiidcB ', and Parastacidce , or true crawfish, are nearly allied. Among the 

 former, the Norway lobster {Nephrops} is smaller than the common lobster, and 

 has the pincers long, slender, and covered with scale-like tubercles. The common 

 lobster (Astacus gammarus), from a commercial point of view, is one of the most 

 important Crustaceans. The crawfish (Potamobiidce) , which live exclusively in 

 fresh water, are very like small lobsters; the species known a.s Potamobia fluviatilis 



COMMON PRAWN. 

 (Natural size.) 



being found in many streams in England. Throughout the day crawfish usually 

 lurk under stones or the edge of banks, and creep out in the evening in search of 

 food, which consists of worms, water insects, small frogs or fish, and plants and 

 roots of many kinds. During the winter they seek the shelter of crevices or 

 excavate deep burrows in the banks. In these they lie, with their antennae 

 stretched forward, and their claws ready to seize any passing object that may serve 

 for prey. Pairing takes place in the autumn, and the female retires to her winter 

 quarters to deposit her eggs, which vary in number from one to two hundred. 

 After being laid, the eggs are attached to the abdominal limbs of the mother. 

 During the winter they develop slowly and are not ready to hatch until late in the 

 spring or the early summer. The young, which at first much resemble the parent 

 and go through no metamorphosis, adhere tightly to heir mother's limbs, and do not 



