152
WERNER BERGMANN
TABLE IX {Continued)
Classification
Order Aspidochirota
Family Holothuriidae
Holothuria princepo (96)
Stichopus japonicus (99)
Class Echinoidea (sea urchins)
Order Aulodonta^
Family Diadematidae
Diadema antillarum (96)
h
Order Stirodonta
Family Arbaciidae
Arbacia punctulata (186)
Order Camarodonta
Family Strongylocentrotidae
Fat
content
of total
(%)
—
2
—
2
Strongylocentrotus
pulcherrimus
(158)
Family Toxopneustidae
Tripneustes esculentus (96)
Family Echinometridae
Echinometra subangularis (89)
Order Clypeastroida
Family Scutellidae
Echinarochnius pasma (89)
Family Clypeastridae
Clypeaster japonicus (189)
—
—
1
1
1.7
Unsaponifiable
fraction
of fat
(%)
11
17
20
25
—
26
33
14
19
Sterol of
unsaponifiable
fraction
(%)
10
7
—
42
—
—
43
42
65
Rotation [ Acetate, +4
Sterol, 0
Cholesterol
Cholesterol
Cholesterol
Cholesterol
Cholesterol
Cholesterol
Cholesterol
0 Former order: Diadematoidea.
h Centrechinus.
common somasteroid ancestor. Whatever the outcome of the controversy
will be, it is certain that comparative biochemical evidence will weigh
heavily in the final judgment.
X. Sterols of Chordates
The phylum of Chordata includes the very interesting group of
animals which bridge the gap between the invertebrates and the vertebrates. With the exception of the fishlike lancelets, Amphioxus, they
resemble invertebrates in their external appearance, but they share with
the vertebrates the possession of a notochord and pharyngeal respiration
Unfortunately almost nothing is known about the sterols of these protochordates. Only a few of their most accessible representatives, the sea