Fie. 13.— Astacus fluviatilis. —The alimentary canal and livers seen from 
above (nat. size). bd, bile-duct ; ez, cecum ; cs, cardiac portion of 
stomach, the line pointing to the cardiac ossicle ; hg, hind-gut ; mg, 
mid-gut ; ye, pterocardiac ossicle ; ps, pyloric portion of stomach, 
the line pointing to the pyloric ossicle ; », ridge separating mid-gut 
from hind-gut ; zc, zygocardiac ossicle. 
F 
