The difference between regular and irregular echinoids

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  • Created by: naomi
  • Created on: 05-01-14 14:32
Shape: Hemispherical/round/dome
Regular
1 of 22
Labrum: not present
Regular
2 of 22
Size of tubercles: tubercles smaller, closer together
Irregular
3 of 22
Anterior groove: present
Irregular
4 of 22
Shape: heart shaped
Irregular
5 of 22
Symmetry: 5 fold radial symmetry
Regular
6 of 22
Position of mouth: centre of oral surface (bottom), contains jaws
Regular
7 of 22
Size of tubercles: tubercles large, well spaced out
Regular
8 of 22
Labrum: present
Irregular
9 of 22
Shape of ambulacra and pore pairs: ambs extended from apical system to mouth, one pair of pores per plate, pores round and close set
Regular
10 of 22
Fasciole: smooth bands of ciliated spines
Irregular
11 of 22
Plastron: not present
Regular
12 of 22
Position of ****: in centre of apical system in centre of aboral surface
Regular
13 of 22
Position of mouth: lies either in centre of oral surface or towards anterior margin and lacks jaws
Irregular
14 of 22
Apical system: does not enclose the periproct it is small and may be linear
Irregular
15 of 22
Fasciole: not present
Regular
16 of 22
Shape of ambulacra and pore pairs: ambs petaloid on top surface online, one pair of pores per plate, pores round and close set except when respiratory tube feet present - then may be elongated
Irregular
17 of 22
Position of ****: outside the apical system in the posterior interambulacrum - migrated to rear or bottom surface
Irregular
18 of 22
Apical system: 10 plates, arranged in 1 or 2 rings around the periproct
Regular
19 of 22
Plastron: present
Irregular
20 of 22
Symmetry: bilateral symmentry
Irregular
21 of 22
Anterior groove: not present
Regular
22 of 22

Other cards in this set

Card 2

Front

Labrum: not present

Back

Regular

Card 3

Front

Size of tubercles: tubercles smaller, closer together

Back

Preview of the front of card 3

Card 4

Front

Anterior groove: present

Back

Preview of the front of card 4

Card 5

Front

Shape: heart shaped

Back

Preview of the front of card 5
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