Russian Journal of Marine Biology, Vol. 29, Suppl. 1, 2003, pp. S46–S56.
Original Russian Text Copyright © 2003 by Biologiya Morya, Ereskovskii.
1063-0740/03/2901-S $25.00 © 2003
Sponges are a group of sessile water lower multicel-
lular organisms that have neither any pronounced intes-
tine nor intestinal parenchyma. Moreover, they have
neither nerve nor muscle tissue. In their bodies there are
mobile totipotent cells, capable of differentiation into
any other type of cells. In many species there are sili-
ceous or calcareous spiculae. The aquiferous system is
considered the most peculiar and genuine characteristic
of sponges. The major physiological functions of this
system are delivery and excretion of food particles, gas
exchange, and withdrawal of gametes and larvae. The
aquiferous system of sponges comprises the following
components: (1) pores (ostia); (2) incurrent canals;
(3) apopyle; (4) choanocyte (collar) chamber; (5) pros-
opyle; (6) excurrent canals; and (7) osculum (Fig. 1).
The unidirectional current of water through the body of
the sponge is produced by ﬂagellated collar cells (cho-
anocytes) united into chambers or canals.
A characteristic feature distinguishing Porifera
from other Metazoa might be considered the high plas-
ticity of their anatomical, tissue, and cellular structures
throughout the life cycle. Different differentiated cells
of sponges are capable of movement, transdifferentia-
tion, and exchange of some functions for some other
ones. Both morphogeneses and functional integration
in sponges are possible only at the basis of mobility and
reorganization of cells and cell populations. Owing to
this characteristic, the sponge continually remains in
the condition of rearrangement of all its structures
[6, 25, 26, 48, 50, 65, 71, 81]. The direct dependence of
sponges on environmental conditions and their plastic-
ity results in the fact that they continuously change the
shape of their bodies; frequently occurring processes
are reduction, fragmentation, fusion, or separation of
individuals in one clone [33, 49, 60, 70].
Problems of Coloniality, Modularity, and Individuality
in Sponges and Special Features of Their Morphogeneses
During Growth and Asexual Reproduction
A. V. Ereskovskii
St. Petersburg State University, St. Petersburg, 199034 Russia
Received December 13, 2001
—A comparative analysis of the organization of sponges has been carried out to clarify problems of
their coloniality, individuality, and modularity. The morphological, physiological, morphogenetic, and immu-
nological aspects of the problem have been analyzed. The followers of the hypothesis of colonial organization
of sponges interpret the process of “new zooid” formation as an “incomplete asexual reproduction.” A compar-
ative analysis of morphogeneses in sponges during growth processes and asexual reproduction has clearly
shown them to be different. A rearrangement (remodeling) of structures accompanied by disorganization and
reorganization of tissues in neighboring elements of aquiferous system is the basis of growth. Migration of
polypotent and secretory cells into the core of bud development is the major mechanism of budding. The for-
mation of new aquiferous units (aquiferous modules) does not represent an “incomplete asexual reproduction.”
Thus, the terms “colony” and “zooid” cannot be applied to the sponges. A morphologically separate sponge,
irrespective of its level of organization (ascon, sycon, or leucon) and the number of oscula (aquiferous modules)
should be considered as an individual.
sponges, colony, modular nature, individual, morphogenesis, growth, budding.
Scheme of the structure of a monooscular sponge
(from Weissenfels ); (
) apopyle; (
) excurrent canal;
) osculum; (
) pore; (
) incurrent canal; (
) spicula; (
) choanocyte chamber.