SPAWN OF THE SEA
"The dewdrop slips into the shining sea."
So Edwin Arnold. Here is an observation illustrating the manner in which certain pellucid sea-drops materialise and ultimately shed themselves as living organisms "into the shining sea."
On November 6, 1908, the sea tossed up on the beach an exceptionally large and absolutely perfect specimen of the egg-cluster of that spacious and useful mollusc known as the Bailer Shell (MELO DIADEMA or CYMBIUM FLAMMEUM). Its measurements were: length, 16¼ in.; circumference at base, 12¾ in.; at middle, 11¼ in.; at apex 7 1/8 in. It weighed 1¾ lb. and comprised 126 distinct capsules. The photograph presents a candid likeness.
During the same month and the first two weeks of December portions of several other egg-clusters came ashore, and as they were in nicely graduated stages of development I was enabled to indulge in an exceptionally entertaining study—no less than the observation of the transformation of glistening fluid into solid matter and life. In passing it may be mentioned that the first and the last two months of the year appear to constitute the period when the offspring of the species see the light of day, proving that the natural impulses of some molluscs are subject to rule and regulation similarly to those of birds and other terrestrial forms.
Each of the capsules composing the cluster is a cone with the apex free and interior, while the base is external and adherent to its immediate neighbours, but not completely so throughout its circumference. It follows, therefore, that the cluster of capsules is hollow and that water flushes it throughout. In appearance it resembles a combination of the pineapple and the corncob, and to the base a portion of the coral-stem to which it had been anchored by its considerate parent was firmly attached.
When the cluster of capsules (the substance of which is tough, semi-transparent, gelatine, opal-tinted, soon to be sea-stained a yellowish green) is slowly expelled from the parent's body—I have been witness to the birth—each contains about one-sixth ounce of vital element, fluid and glistening. Physical changes in this protoplasm manifest themselves in the course of a few days. The central portion becomes a little less fluid, and from an inchoate blur a resemblance to a diaphanous shell develops and floats, cloud-like, in a perfectly limpid atmosphere. Gradually it becomes denser though still translucent, as it seemingly absorbs some of the fluid by which it is surrounded. The model of the future animal, exact even to the dainty contours and furrows around that which represents the spire of the ultimate shell, is still without trace of visible organs. That, however, its substance is highly complex is obvious, for as imperceptible development progresses the exterior is transformed into a substance resembling rice tissue-paper—an infinitely fragile covering—which from day to day insensibly toughens in texture and becomes separate from the animal. Faint opaque, transverse ribs are at this stage apparent, though disappearing later on. Opacity is primarily manifested at the aperture of the infant mollusc where a seeming resemblance to an operculum forms, possibly for the protection of vital organs during nascency. This plaque of frail armour is, however, soon dismantled, and of course much more happens in the never-ceasing process than is revealed to the uninitiated.
As the calcareous envelope becomes opaque and solid, the animal within loses its transparent delicacy, and coincidentally the apex of the capsule opens slightly. In the meantime the fluid contents have disappeared, as if the animal had resulted from its solidification. The animal, too, is a very easy fit in its compartment, and incapable, in its extreme fragility of withstanding the pressure of a finger. Now it begins to increase rapidly in bulk and sturdiness; the shell becomes hard, and as the exit widens it screws its way out of a very ragged cradle, emerging sound and whole as a bee from its cell, all its organs equipped to ply their respective offices.
With pardonable affectation of vanity it has finally fitted itself for appearance in public by the assumption of three or four buff and brown decorations upon its milk-white shell, which quickly blend into a pattern varying in individuals, of blotches and clouds in brown, yellow, and white. In maturity the mollusc weighs several pounds, its shell has a capacity for as much as two gallons of water, and is coloured uniformly buff, while in old age infantile milk-white reasserts itself.
It is not for such as I am in respect of the teachings of science to say whether the development of the perfect animal from a few drops of translucent jelly—as free from earthly leaven as a dewdrop—is to be more distinctly traced, in the case of this huge mollusc than in other elementary forms. All that it becomes an unversed student of life's mysteries to suggest is that this example gives bold advertisement to the marvellous process.