Fig. is.— Astacn.<?Jf.nviafilU. —The alimentary canal and livers seen from 

 above (nat. size), bd, bile-duct ; co', caecum ; cs, cardiac portion of 

 stomach, the line pointing to the cardiac ossicle ; /iff, hind- gut ; wg, 

 mid-gut ; pc, pterocardiac ossicle ; ps, pyloric portion of stomach, 

 the line pointing to the pyloric ossicle ; r, ridge separating mid-gut 

 from hind-gut ; zc, zygocardiac ossicle. 



