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

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