148 CRUSTACEA. 



External antennae furnished with 

 a small, arrow-shaped, moveable plate Astacida. 



External antennae with no move- 

 able plate. 



Abdomen long and slender ; breast- 

 plate linear ; body lengthened . . . Thalassinada. 



Abdomen short or moderate ; breast- 

 plate very large ; body depressed . . Palinuridae. 



FAMILY I. PENEAD^. 



Penceus (Fabr.). First three pairs of feet two- 

 fingered ; false feet much enclosed by the abdomen, 

 and terminated by two ciliated plates. 



P. Caramote. Fig. 276 ;.*. 



PasipJicea (Sav.). First and second feet two- 

 fingered ; body compressed and lengthened ; beak 

 very short and simple. 



P. Sivado. Fig. 277 ;.*. 



FAMILY II. PAL^EMONID^E. 



Palcemon (Fabr.). Inner antennae terminating 

 in three filaments ; first and second feet two- 

 fingered; the second much larger than the first; 

 beak long, and compressed. 



P. serratus. 



squilla. Fig. 278 ; n. s. 



Leachii. 



varians. 



Pandalus (Leach). Inner antennae terminating 



