Key:  Phylum Porifera

Taken primarily from  Kozloff, 1987, 1996 p. 6 (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)

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Lower taxonomic level	Main Page	Alphabetic Index	Systematic Index	Glossary

1a	Spicules calcareous (can be dissolved by hydrochloric acid) and belonging to 3 or 4 main types (tetract, triact, oxeas) (species occurring in our region are usually white, occasionally light tan, and generally less than 10 cm in size).  [These sponges have no spongin]	Class Calcarea
1b	Spicules (these are absent in the Demospongiae genera Aplysilla, Hexadella, Dysdea, and Halisarca) silicious (are not dissolved by hydrochloric acid)	2
2a	Basic spicule type 6-rayed, but often modified by reduction or loss of certain rays; in our species, the dominant large spicules are either fused together to for, a lattice or cover the species as a feltlike mat; typically white or yellow, unless covered by silt, and larger than 10 cm; strictly subtidal, at depths of more than 15 cm	Class Hexactinellida
2b	Spicules (unless absent, as in exceptions noted in choice 1b), not basically 6-rayed; spicules not fused to form a lattice, although in some cases they are held firmly together by fibers of spongin; some species white or dull tan, but others colorful; includes most of the intertidal and subtidal species in our region	Class Demospongiae

  Class Calcarea
  Class Demospongiae
  Class Hexactinellida