Bergquist, P. R. 1978. Sponges. Berkeley, University
of California Press. Excellent monograph
on sponge structure, classification,
evolution, and general biology.
Grell, K. G. 1982. Placozoa. In S. P. Parker (ed).
Synopsis and classification of living organisms,
vol. 1. New York, McGraw-Hill Book
Company. Synopsis of placozoan characteristics.
Hartman, W. D. 1982. Porifera. In S. P. Parker
(ed). Synopsis and classification of living
organisms, vol. 1. New York, McGraw-Hill
Book Company. Review of sponge classification.
Simpson, T. L. 1984. The cell biology of
sponges. New York, Springer-Verlag. A
review and synthesis, noting many problems
yet to be solved.
Wainright, P. O., G. Hinkle, M. L. Sogin, S. K.
Stickel. 1993. Monophyletic origins of the
Metazoa: an evolutionary link with Fungi.
Science 260:340–342. Reports molecular
evidence that the sister group of metazoans
is Fungi and that multicellular animals,
including sponges, are monophyletic.
Wood, R. 1990. Reef-building sponges. Am. Sci. 78:224–235. The author presents evidence
that known sclerosponges belong to either the
Calcarea or the Demospongiae and that a
separate class Sclerospongiae is not needed.