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WERNER BERGMANN
sterol mixture. It may therefore be regarded as significantly different
from other species of this genus.
The data on sterols from other sponges of the class of Demospongia
are too fragmentary to permit their correlation to taxonomic aspects. It
is of interest, however, that only ChondriUa nucula (86) of the order
Carnosa has been found to contain a A
7 -sterol, chondrillasterol (III,
R = M), as a major component of the sterol mixture. This family includes sponges of such unspongelike appearance and consistency as to
merit its separation into a special order. As yet nothing is known about
the sterols of the very attractive glass sponges of the class of Hyalospongiae. Sponges belonging to the class of Calcispongiae are generally
quite small and poor in organic matter. The one exception is the
Bermuda species Leucetta floridana, which is of comparatively gigantic
size. The sterol content of its unsaponifiable fraction appears to be
quite low, and this may well be true for other sponges of this class
(89).
V. Sterols of Coelenterates
The unusual diversity of sponge sterols, appealing as it is to the
steroid chemist, should not be overvalued in tracing the biochemical
history of the sterols. The sponges constitute a rather special group of
animals. They are regarded as a very early and probably polyphyletic
branch off the main stem of evolution, and hence as ancestrally unrelated to animals of other phyla. It is therefore of considerable interest
that a similar variety of sterols is encountered also among the coelenterates, a phylum of animals less primitive than the sponges and more
representative of the main stream of evolution (92).
The lipid content of coelenterates is generally rather high, particularly when expressed in terms of the organic matter of the animal
rather than its total weight. In certain sea anemones the lipids constitute as much as one-third of the dry weight of the animal. The
lipids are unusually rich, as high as 50%, in such waxlike materials as
cetyl palmitate (93) or myristyl myristate (92). These esters or their
homologs may be regarded as some of the most typical components of
coelenterates (8). Because of their presence, the unsaponifiable fractions of coelenterate lipids are generally so rich in higher aliphatic alcohols as to make the separation of the sterols at times rather difficult.
Our knowledge of coelenterate sterols is still quite fragmentary. It
includes but one representative each of the classes Hydrozoa and
Scyphozoa (see Table IV). They both contain cholesterol, which is also
present in many of the sea anemones. Because they are quite conspicuous, easy to collect, and rich in lipids, the sea anemones have so
WERNER BERGMANN
sterol mixture. It may therefore be regarded as significantly different
from other species of this genus.
The data on sterols from other sponges of the class of Demospongia
are too fragmentary to permit their correlation to taxonomic aspects. It
is of interest, however, that only ChondriUa nucula (86) of the order
Carnosa has been found to contain a A
7 -sterol, chondrillasterol (III,
R = M), as a major component of the sterol mixture. This family includes sponges of such unspongelike appearance and consistency as to
merit its separation into a special order. As yet nothing is known about
the sterols of the very attractive glass sponges of the class of Hyalospongiae. Sponges belonging to the class of Calcispongiae are generally
quite small and poor in organic matter. The one exception is the
Bermuda species Leucetta floridana, which is of comparatively gigantic
size. The sterol content of its unsaponifiable fraction appears to be
quite low, and this may well be true for other sponges of this class
(89).
V. Sterols of Coelenterates
The unusual diversity of sponge sterols, appealing as it is to the
steroid chemist, should not be overvalued in tracing the biochemical
history of the sterols. The sponges constitute a rather special group of
animals. They are regarded as a very early and probably polyphyletic
branch off the main stem of evolution, and hence as ancestrally unrelated to animals of other phyla. It is therefore of considerable interest
that a similar variety of sterols is encountered also among the coelenterates, a phylum of animals less primitive than the sponges and more
representative of the main stream of evolution (92).
The lipid content of coelenterates is generally rather high, particularly when expressed in terms of the organic matter of the animal
rather than its total weight. In certain sea anemones the lipids constitute as much as one-third of the dry weight of the animal. The
lipids are unusually rich, as high as 50%, in such waxlike materials as
cetyl palmitate (93) or myristyl myristate (92). These esters or their
homologs may be regarded as some of the most typical components of
coelenterates (8). Because of their presence, the unsaponifiable fractions of coelenterate lipids are generally so rich in higher aliphatic alcohols as to make the separation of the sterols at times rather difficult.
Our knowledge of coelenterate sterols is still quite fragmentary. It
includes but one representative each of the classes Hydrozoa and
Scyphozoa (see Table IV). They both contain cholesterol, which is also
present in many of the sea anemones. Because they are quite conspicuous, easy to collect, and rich in lipids, the sea anemones have so