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

abdomen abdominal appendages abdominal somites alimentary canal ambulatory limbs Amurland animals antenna antennule aperture appears artery arthrobranchiæ Astacine Astacus fluviatilis Astacus torrentium attached basal joint blastomeres blood body branchiæ branchial cavity branchiostegite carapace cardiac cavity cephalothorax cervical groove chelate chitinous convex corpuscles coxopodite cray Crustacea cuticle cuticular division ecdysis edge endopodite English crayfish epiblast epipodite exopodite exoskeleton eye-stalk fact female filaments forceps front ganglia ganglion gastrolith genus gills give rise green gland hind-gut hinder hypoblast inner integument lateral leptodactylus less lobster longitudinal male mid-gut morphological muscle nerve fibres nobilis noble crayfish nucleated cells nuclei organs ossicle outer pairs plate pleura podobranchia portion posterior prawns present 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