266 



CRUSTACEANS, 



and the antennae are not furnished with an external scale-like basal piece. The 

 best known members of this group are the Palinuridce, or rock-lobsters, one member 

 of which, the crawfish (Palinurus vulgaris), may be seen for sale in England. 



It is larger than the lobster, 

 and has enormously long stout 

 antennae, and a spiny carapace 

 but no claws. This species is 

 figured on the left side of 

 the coloured Plate. The second 

 family, Scyllaridce, contains a 

 considerable number of genera 

 (Scyllarus ,Ibacus, etc.), mostly 

 from tropical seas, remarkable 

 for having the carapace broad 

 and flattened, with the eyes 

 enclosed in complete orbits on 

 its upper surface, and the 

 antennas short and scale-like. 

 In this tribe the larvae are 



LARVA OP CRAYFISH, THE SO-CALLED 'GLASS-CRAB (nat. size). Unlike thoS6 of Crabs Or 



lobsters. On account of their 



transparency and delicacy they are called glass-crabs. The body is formed of three 

 distinct parts, a large round-sided head, a smaller but also round-sided thorax, and 

 a minute jointed abdomen which projects like a short tail from the hinder end of 

 the thorax. The abdomen bears no limbs. 



The lobsters and crayfish (Astacidea), have at least three pairs of the 

 large thoracic limbs pincer-like, the first being much larger than the others. The 



SLENDER- CLAWED CRAYFISH, Willemccsia leptodactyla (nat. size). 



