An Introduction to the Study of Zoology, Illustrated by the Crayfish

abdomen abdominal appendages abdominal somites alimentary ambulatory limbs Amurland animals antenna antennule aperture appears artery arthrobranchiæ Astacine Astacus torrentium attached basal joint becomes blood body branchiæ branchial branchial cavity canal carapace cardiac cavity cephalothorax cervical groove chelate chitinous corpuscles coxopodite cray Crustacea cuticle cuticular division ecdysis edge endopodite endosternites epiblast epipodite exopodite exoskeleton eyestalk fact female filaments fluviatilis fluviatilis.-A food-yelk forceps front ganglia ganglion gastrolith gastrula genus gills gives rise hind-gut hinder hypoblast inner integument lateral leptodactylus less lobster longitudinal male mandible mid-gut morphological muscle muscular nerve fibres nobilis nucleated cells nuclei organs ossicle outer ovum pairs plate pleura podo podobranchiæ portion posterior prawns present procephalic pyloric region ridge rostrum segments septal lines setæ side somite species spermatozoa spines sternal sternum stomach structure substance surface swimmerets telson tergal tergum terminal thoracic thoracic limbs thoracic somite tissue transverse wall yelk zone