LOBSTER.* 



A. EXTEKNAL CHARACTERS. 



I. The hardened cuticle, the exoskeleton, covering 



the animal. 



II. The body, consisting of: 



1. An anterior part, the cephalothorax, with a 



firm continuous covering above (carapace). 

 Parts of carapace : 



(a) Cephalic part, covering the head of 

 the lobster ; prolonged anteriorly into 

 the frontal spine, on each side of which 

 is a depression containing the stalked 

 eye ; limited posteriorly by the cervi- 

 cal groove which separates it from : 

 (6) Thoracic part, covering the thorax, con- 

 sisting of: 



(aa) Median dorsal part, separated by a 

 very slight groove on each side, 

 the branchio-cardiac groove, from : 

 (bb) Two lateral parts, one on each side, 

 the branchiostegites, which protect 

 the gills. 



* If lobsters cannot be obtained in the market, these directions 

 will answer nearly as well for the crayfish. 



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