Key: Family Mactridae
Phylum Mollusca
Class
Bivalvia
Subclass Heterodonta
Order Veneroida
Taken primarily from Kozloff,
1987, 1996 p. 278 (Copyright
1987, 1996, University of
Washington Press. Used in this web page by permission of University
of Washington Press)
| 1a |
Width of gape at posterior
end more than 1/4 the width of the shell; length
sometimes attaining 20 cm; burrowing in mud and clay, intertidal and
subtidal |
2 |
| 1b |
Width of gape at posterior
end less than 1/4 the width of the shell; length
rarely exceeding 10 cm; mostly in sand, and primarily subtidal |
Spisula (Symmorphomactra) falcata |
| 2a |
Shell generally about 1.5x as long
as high;
umbones
near the
end of the anterior
third; common and widely distributed in our region |
Tresus
capax |
| 2b |
Shell more than 1.5x as long
as high;
umbones
near the
end of the anterior
quarter; uncommon in our region |
Tresus nuttallii |
Taxonomic
Levels Represented
in This Key:
Tresus capax
Page created by Dave Cowles, 2005
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