| 1a |
Relatively large worms, length often
exceeding 10 cm, width often
exceeding 1 cm; not secreting tubes; posterior one-third of the body,
behind
the region bearing gills, without setae,
and therefore resembling a teai; gills pinnate
or bushy |
2 |
| 1b |
Small worms, up to about 2.5 cm long and 0.5 mm
wide; secreting membranous
tubes coated with fine sand; gills and setae
continuing nearly to the posterior end of the body, so that there is
nothing
that resembles a tail; gills consisting of 1-4 simple filaments |
Branchiomaldane simplex |
| 2a |
With several pairs of esophageal caeca,
those of 1 pair being much longer than the others; neuropodia
of more posterior gill-bearing segments not closely approaching the
midventral
line |
3 |
| 2b |
With only 1 pair of esophageal caeca;
these short; neuropodia
of more posterior gill-bearing segments closely approaching the
midventral
line |
Arenicola marina |
| 3a |
Nephridiopores
completely exposed; with 4-7 pairs of esophageal caeca;
typically inhabiting muddy sand at the inner margins of bays |
Abarenicola
pacifica |
| 3b |
Ventral portions of nephridiopores
covered by a flap of skin; with 8 or more pairs of esophageal caeca;
typically inhabiting rather clean sand at the mouths of bays or on
beaches
exposed to some wave action |
4 |
| 4a |
Usually with 8-12 pairs of esophageal caeca;
usually on beaches exposed to some wave action |
Abarenicola claparedi subsp. oceanica |
| 4b |
Usually with 12-19 pairs of esophageal caeca;
usually near the mouths of sandy bays |
Abarenicola claparedi subsp. vagabunda |