As to the animal which commonly and sometimes scientifically bears the name of Star-fish, in walking on the sea-shore at low tide, your eyes have often seen this strange creature half buried in the sand. It is so regular and geometrical in its form that it has more the appearance of being the production of man's hand than of a creation which breathes and moves. The Divine Geometrician who created it never realised a creature more regularly finished in shape, or more perfectly harmonious in symmetry.
The star-fish has five perfectly equal arms. They resemble a cross of honour, which has five branches. The star of the brave, the star of honour—these somewhat trivial words recall, nevertheless, the resemblance which exists between the two objects; doubtless, man has here taken Nature for his copy. It must, however, be remarked that, though five is the general number of lines in the star-fish, this number is not constant; it varies with different genera, species, and even with individuals. The connection of the arms with the disk presents equally remarkable differences. In the genus Culcita, the disk is so much developed that it constitutes, so to speak, the entire animal, whilst the arms form only a slight protuberance upon its circumference. In the genera Luidia, on the contrary, the disk is reduced to minimum, whilst the arms are of great length and very slender.
Fig. 105. Asterias rubens (Lamarck).
The colours of the star-fish vary greatly; they vary from a yellowish-grey, a yellow-orange, a garnet-red, to a dark violet, as their name indicates.
Star-fishes are exclusively and essentially beings of the sea; they are never seen in fresh water; they dwell amongst the submarine herbage, seeking for sandy coasts; they generally are found at moderate depths, but there are some species which are found at the great depth of a hundred and fifty fathoms.
Asterias are met with in almost every sea and under all latitudes, but they are most numerous and their forms are more richly varied in the seas of tropical regions. There are about a hundred and forty species described.
