Subdecks (5)

Cards (72)

  • Composed of the spiders, scorpions, ticks, mites and allies; Largest and most important chelicerates
  • Nervous organs
    sensory hairs (trichobothria), eyes, and slit senses
  • Body segments
    cephalothorax and abdomen
    ○ "Head” portion has sensory hairs and eyes (compound and simple)
    4 appendages attached to cephalothorax; the two anterior pairs for feeding and the rest for movement.
    ○ Abdomenhas minute pore openings (spiracles), leads to internal lamellae called book lungs
  • Circulation
    heart → dorsal anterior & posterior aortasmall arteriestissue spaces/sinuseslarge ventral sinusbook lungsvenous channelspericardiumostiaheart
  • Excretion
    coxal glands- thin-walled spherical sacs along the sides of the prosoma that collect wastes from the surrounding blood
  • Reproductive
    Dioecious, has single or paired gonads in the abdomen, sperm transfer is indirect and through spermatophores, and ducts exit through the genital orifice.
  • Nervous System
    • Protocerebrum- contains the optic centers and optic nerves
    • Tritocerebrum- contains the nerves supplying the chelicerae
    • A collar or ring surrounding the esophagus
    • Ganglia has fused with the subesophageal ganglion