NOTES ON THE OPHIUEANS, OH THE SAND AND BRITTLE STARS. 339 
remain, and another is formed during the metamorphosis — a 
statement open to very considerable question. Years rolled on, 
and nerves, which once gave the clue to classification, became 
of as little importance as water systems, and stomachs reigned 
supreme as zoological guides. And Haeckel, faithful to his stomach 
as a zoological loadstone, noticing that in Star-fish the viscus is 
carried into each ray, infers that the animal is a colony of 
worms, united by a common head. Leaving this stroke of 
genius for what it is worth, it is simply necessary to remark 
that the last and the most remarkable phase of thought, separates 
the Echinodermata from the worms and Coelenterates, and 
establishes them as a sub-kingdom divided into classes and 
orders. The classes are the Crinoidea, the Asteroidea, the 
Echinoidea, and the Holothurida ; and the orders of the 
Asteroidea are the Asterida or Star-fish, and the Ophiurida, 
these last being divided into the sub-orders Ophiurae and 
Euryaleae. 
The great fault of this classification is, the too close union of 
the Star-fish and Ophiurans, for these last differ very consider- 
ably from the others in their embryology, and require a class of 
their own. 
Everybody who has visited the seaside, has seen a Star-fish and 
a Sea Urchin ; Sea Cucumbers are common in every aquarium of 
importance ; and what are scientifically called Ophiurans, and 
popularly Brittle Stars and Sand Stars are to be seen dried, or 
in bottles, in every museum. Sometimes these last are seen 
as waifs and strays on the shore, and perchance on cleaning a 
cod’s stomach they may be turned out by the score. The most 
unobservant know all these things at a glance. They have 
something very decidedly in common, except the Sea Cucumbers, 
which links them together, such as the hard and somewhat 
spiny shell, the feelers by which they move, and the rayed 
appearance, and the youngest zoologist would classify them 
together. There is another group of these hard-skins, beautiful 
in shape, elegant in movement, and often dwellers on the floor 
of the deepest seas ; but these, the Feather Stars or Sea Lilies, are 
not so well known except to naturalists by education. 
It is interesting and also somewhat important, in examining 
into the life history of these groups to know that they are all 
very old dwellers in the seas. Very early in the world’s history 
there were Feather Stars ( Grinoids ), Star-fish ( Asteriadce ), and 
Sand Stars (Ophiurans); the Urchins (Echini) came a little 
later, but still in the palaeozoic ages, and there are relics of the 
Sea Cucumber series in the Carboniferous rocks. No very great 
amount of structural change has occurred, as a whole, in the 
group since palaeozoic times, and the types were thus distinct 
ages ago — that is to say, in Silurian times the Star-fish and 
