Do not, therefore, reproach him with vanity or curiosity, if you see him so often protrude his magnificently decorated head; but rejoice rather that this habit, to which necessity obliges him, gives you a better opportunity for closer observation. Place only a shell or stone covered with _serpulas_ or _cymospiras_, into a vessel filled with sea-water, and you will soon see how, in every tube, a small round cover is cautiously raised, which hitherto hermetically closed the entrance, and prevented you from prying into the interior. The door is open, and soon the inmate makes his appearance. You now perceive small buds, here dark violet or carmine, there blue or orange, or variously striped. See how they grow, and gradually expand their splendid boughs! They are true flowers that open before your eye, but flowers much more perfect than those which adorn your garden, as they are endowed with voluntary motion and animal life.
[Illustration: Serpula, attached to a Shell.]
At the least shock, at the least vibration of the water, the splendid tufts contract, vanish with the rapidity of lightning, and hide themselves in their stony dwellings, where, under cover of the protecting lid, they bid defiance to their enemies.
Not all the tubicole annelides form grottos or houses of so complete a structure as those I have just described. Many content themselves with agglutinating sand or small shell-fragments into the form of cylindrical tubes. But even in these inferior architectural labours of the _Sabellas_, _Terebellas_, _Amphitrites_, &c., we find an astonishing regularity and art; for these elegant little tubes, which we may often pick up on the strand, where they lie mixed with the shells and algæ cast out by the flood, consist of particles of almost equal size, so artistically glued together, that the delicate walls have everywhere an equal thickness. The form is cylindrical, or funnel-shaped, the tube gradually widening from the lower to the upper end. Some of these tubicoles live like solitary hermits, others love company; for instance, the _Sabella alveolaris_, which often covers wide surfaces of rock, near low-water mark with its aggregated tubes. When the flood recedes nothing is seen but the closed orifices; but when covered with the rising waters, the sandy surface transforms itself into a beautiful picture. From each aperture stretches forth a neck ornamented with concentric rings of golden hair, and terminating in a head embellished with a tiara of delicately feathered, rainbow-tinted tentacula. The whole looks like a garden-bed enamelled with gay flowers of elegant form and variegated colours.