Backboneless. Sponge

1.

backboneless

2.

sponge

3.

flatworm

4.

earthworm

5.

leech

6.

coelenterates

7.

actinia

8.

medusa (jellyfish)

9.

comb-bearer

10.

jointed-legged
animals

11.

lobster

12.

rock lobster

13.

crab

14.

soldier crab

15.

shrimps

16.

echinoderms

17.

starfish

18.

sea-urchin

19.

sea cucumber (holothuria)

20.

brittle star

21.

squids

22.

squid

23.

cuttlefish

24.

octopus

25.

gigantic octopus

26.

nautilus

27.

bivalved mollusks

28.

oysters

29.

scallops

30.

mussels

31.

gastropods

32.

snail

33.

rapa whelk

34.

sea-ear