146
WERNER BERGMANN
and consisted mainly of astrol first isolated from starfish by Kossel
(172) and subsequently identified as batyl alcohol (181).
Table IX includes species typical of all three recognized orders of
Asteroids. The basic order of Phanerozonia, which is believed to have
given rise to the Spinulosa and Forcipulata (182), is particularly well
represented by families. Only species from the Australian Ondonasteridae and the deep-sea family of Benthopectinidae are missing from a
comprehensive coverage of this order. The important families of the
Spinulosa are also adequately covered, and only the Pterasteridae, the
cushion stars, and the small borderline family of Ganeriidae, including
starfish from antarctic and subantarctic regions, still merit attention.
Among the Forcipulata only the large family of Asteriidae has so far
been investigated. Data on species from the deep-sea families of Zorioasteridae and Brisingidae, which are possibly related to Ophiuroids,
are desirable for a satisfactory completion of the picture.
The most outstanding fact to be derived from Table IX is the
ubiquity of A
7 -sterols in asteroids. The small rotations of the crude and
purified products clearly show that such sterols are the principal if not
exclusive components of the sterol mixtures so far studied, and it is
reasonable to assume that they are characteristic of all asteroids. It remains a challenging problem, however, to elucidate the compositions of
the sterol mixtures, to identify all its components, and to search for
any connections between them and the classification of asteroids. Such
data might for example be helpful in a reappraisal of the Asteriidae,
which appears to be a polyphyletic aggregation of genera.
The two orders of the ophiuroids (Table IX) are represented by a
reasonably adequate coverage of families. With the exception of some
of the basket stars, Euryalae, most of the ophiuroids are rather small,
and although quite common, they are difficult to obtain in quantities
adequate for a thorough sterol analysis. The rotations of the sterol
mixtures clearly indicate the predominant presence of A
5 -sterols (II).
The A
7 -sterols, which are so characteristic in the starfish, appear to be
absent altogether. In the case of Ophiura sarsi no A
7 -sterol was detected in the sterol mixture by means of Fieser's very sensitive color
test (45). The ophiuroid sterols seem to be rather complex mixtures of
A
5 -sterols, reminiscent of plant sterol mixtures. It is doubtful that any
pure sterol has yet been isolated from ophiuroids, but the presence in
the mixture of cholesterol, clionasterol, poriferasterol, and stigmasterol
has been mentioned (158).
Our present knowledge of the sterols of the crinoids is in a similar
state of advancement. The living species of this class of echinoderms,
which is best known for its fossil record, are all included in one order.
WERNER BERGMANN
and consisted mainly of astrol first isolated from starfish by Kossel
(172) and subsequently identified as batyl alcohol (181).
Table IX includes species typical of all three recognized orders of
Asteroids. The basic order of Phanerozonia, which is believed to have
given rise to the Spinulosa and Forcipulata (182), is particularly well
represented by families. Only species from the Australian Ondonasteridae and the deep-sea family of Benthopectinidae are missing from a
comprehensive coverage of this order. The important families of the
Spinulosa are also adequately covered, and only the Pterasteridae, the
cushion stars, and the small borderline family of Ganeriidae, including
starfish from antarctic and subantarctic regions, still merit attention.
Among the Forcipulata only the large family of Asteriidae has so far
been investigated. Data on species from the deep-sea families of Zorioasteridae and Brisingidae, which are possibly related to Ophiuroids,
are desirable for a satisfactory completion of the picture.
The most outstanding fact to be derived from Table IX is the
ubiquity of A
7 -sterols in asteroids. The small rotations of the crude and
purified products clearly show that such sterols are the principal if not
exclusive components of the sterol mixtures so far studied, and it is
reasonable to assume that they are characteristic of all asteroids. It remains a challenging problem, however, to elucidate the compositions of
the sterol mixtures, to identify all its components, and to search for
any connections between them and the classification of asteroids. Such
data might for example be helpful in a reappraisal of the Asteriidae,
which appears to be a polyphyletic aggregation of genera.
The two orders of the ophiuroids (Table IX) are represented by a
reasonably adequate coverage of families. With the exception of some
of the basket stars, Euryalae, most of the ophiuroids are rather small,
and although quite common, they are difficult to obtain in quantities
adequate for a thorough sterol analysis. The rotations of the sterol
mixtures clearly indicate the predominant presence of A
5 -sterols (II).
The A
7 -sterols, which are so characteristic in the starfish, appear to be
absent altogether. In the case of Ophiura sarsi no A
7 -sterol was detected in the sterol mixture by means of Fieser's very sensitive color
test (45). The ophiuroid sterols seem to be rather complex mixtures of
A
5 -sterols, reminiscent of plant sterol mixtures. It is doubtful that any
pure sterol has yet been isolated from ophiuroids, but the presence in
the mixture of cholesterol, clionasterol, poriferasterol, and stigmasterol
has been mentioned (158).
Our present knowledge of the sterols of the crinoids is in a similar
state of advancement. The living species of this class of echinoderms,
which is best known for its fossil record, are all included in one order.