Page:Popular Science Monthly Volume 6.djvu/173

Rh one of Nature's economic processes; for the pad is absorbed, literally consumed, and the baby-oyster in this way gets a start that secures it a rapid growth—for it should be borne in mind that this is a critical period in the life of this diminutive thing. It is just now that it has to draw so largely on its small capital of vital resources, by directing the growth-force to the one object—a sure anchorage. Thus the secretions labor on the cementation of the lower valve to some solid object. Then comes the general shell-growth, which is very rapid, and at the same time the accelerated internal development; all which amounts to an entire reconstruction.

If, now, to this triple draft, occasioned by the anchoring, the shell-growth, and the development of the internal organs, one should add the necessity of procuring food in the usual amount, and by the usual means, would not the combined demand be exhaustive beyond the little creature's powers and resources? It should be observed, too, that now the food-necessity is more urgent than at any other period of its existence. It is also observable that the banquet prepared is ampler than at any other time. This is surely a striking instance in lowly quarters of a wise conservation of material and force. I am aware that this pad is differently disposed of by some naturalists; that it is said to drop off, and to be wasted; but, as I have witnessed a similar utilization of an otherwise useless member in other larval forms, I believe that observation will establish this view. And how remarkable this internal change, so rapidly progressing in the little oyster! It is a series of almost magic transformations. The eyes—if it had any—are gone. The external cilia, which served it for locomotive and breathing organs, disappear, and within appear true branchiæ, like those of its mother. A stomach, too, is now built up, and the labial fingers are provided. And that tiny, true heart appears, to the music of whose beating the little creature begins in earnest its lifework, as a perfect oyster, although hardly yet larger than the head of a pin. When a month old, it equals a large pea in size; at six months, it is an inch or more in length; at four years, it is large and amply ready for market, or even at three years, if the conditions of growth have been favorable.

—For raising the seed, that is, the young oysters intended to be planted, a hard bottom, with plenty of shells, or objects for attachment of the spat, is desirable. But such a location would not be the place for growing and fattening the adult. A bottom with two or three inches of organic mud, and a hard pan beneath, and that in an estuary, or somewhere commanding a current, and receiving the river-flow, is the best. In this flocculent organic mud is much of the food of the oyster, and this food is in lively motion upon its surface. The algæ, or sea-weeds, often anchor to the shell, and adorn it with fronds of olive, and ruby, and the most exquisite emerald, while the sporules which rain from them are the true