Figure 33.1 Review of animal phylogeny

Figure 33.2 Sponges

Figure 33.3 Anatomy of a sponge

Figure 33.4 Polyp and medusa forms of cnidarians

Figure 33.4bx Jelly medusa

Figure 33.5 A cnidocyte of a hydra

Table 33.1 Classes of Phylum Cnidaria

Figure 33.6 Cnidarians: Hydrozoans (top left), jelly (top right), sea anemone (bottom left), coral polyps (bottom right)

Figure 33.6bx Purple striped jelly, Pelagia panopyra

Figure 33.6dx Coral polyps

Figure 33.7 The life cycle of the hydrozoan Obelia (Layer 3)

Figure 33.8x2 Ctenophore

Table 33.2 Classes of Phylum Platyhelminthes

Figure 33.9x A flatworm

Figure Anatomy of a planarian

Figure The life history of a blood fluke, Schistosoma mansoni

Figure Anatomy of a tapeworm

Figure Basic body plan of mollusks

Table 33.3 Major Classes of Phylum Mollusca

Figure A chiton

Figure The results of torsion in a gastropod

Figure 33.18x Garden snail

Figure Gastropods: Nudibranchs (top left and bottom left), terrestrial snail (bottom left), deer cowrie (bottom right)

Figure A bivalve: Scallop

Figure Anatomy of a clam

Figure Cephalopods: Squid (top left and bottom left), nautilus (top right), octopus (bottom right)

Figure Anatomy of an earthworm

Figure 33.23x External anatomy of an earthworm

Table 33.4 Classes of Phylum Annelida

Figure Annelids, the segmented worms: Polychaete (left), feather-duster worm (middle), leech (right)

Figure 33.24cx Christmas-tree worms

Figure 33.25ax Nematode, C. elegans

Figure 33.25b Parasite nematode, Trichinella spiralis

Figure External anatomy of an arthropod

Table 33.5 Some Major Arthropod Classes

Figure A trilobite fossil

Figure Horseshoe crabs, Limulus polyphemus

Figure Arachnids: Scorpion (left), honeybee air tube filled with parasitic mites (right)

Figure 33.30b Spider anatomy

Figure 33.30x Lycosid spider: female with offspring

Figure 33.31a Class Dipolopoda (millipedes)

Figure Insect flight, dragonfly

Figure 33.x1 Insecta: beetle

Figure Metamorphosis of a butterfly

Figure Crustaceans: Lobster (top left), banded coral shrimp (bottom left), barnacles (right)

Figure 33.0 Ochre sea stars, Pisaster ochraceus

Figure Anatomy of a sea star

Figure Echinoderms: Sea star (top left), brittle star (top right), sea urchin (bottom left), sea lily (bottom right),