Page:Hardwicke's Science-Gossip - Volume 1.pdf/196

"sea-caff,"—probably implying "chaff," something waste and worthless (figs. 13, 14); but they have in general no better designations for the numerous tribe of zoophytes than "sea-weeds," "flowers," or simply "growth." It is in the Flustra hispida, though amongst the most common and apparently worthless objects on the rocks, that the eye of the naturalist has detected beauties and marvels. Nay, on the common Fucus serratus, or "sea-ware," dark brown, consistent-like, gelatinous patches are frequently found on one or both sides of the leaf, occasionally also encircling the stem. Sometimes these occur in such profusion that the leaf is weighed down by them, or if reft from its site, feels heavy in the

hand. What, then, are these excrescences? The numerous inequalities of the surface, both to the naked eye and viewed by a magnifier, offer some resemblance to artificial manufacture, and in some measure justify the name of "rough sea-mat." Another zoophyte of the Mediterranean Sea passes by the same name, but does not correspond in form. But to recur to the wonders of the Flustra hispida. Plunged amidst recent sea-water during genial temperature, a pale thin cloud will speedily be interposed betwixt its dark irregular surface and the spectator's eye; but on the vessel receiving it sustaining a shock, this cloud is instantaneously dispelled, whilst the brownish fleshy substance of the Flustra remains prominent as before. This illusion may be frequently repeated, for the cloudy semblance is produced by hydræ, drawn from the cells into which they had retreated, to revel in the freshness of the renovated element—and the misty shade is caused by the motion of their pale tentacles over the dark ground of the Flustra. So timid and endowed with caution are these minute and active beings, that they sink into concealment on the apprehension of danger, and show by their reappearance their relief from alarm.

But I must proceed no further with this very incomplete notice of a large and interesting group of the wonders of "the deep, deep sea." As cast upon the shore the polypidoms are usually only the uninhabited houses, the inmates dead, and their remains dispersed; but even the untenanted habitations are well worthy a little minute examination, and the living zoophyes will afford a world of delight to the microscopist, and while away many a weary hour of a lounge at the sea-shore.

Many persons are not aware of the fact, that the earthworm really does live upon earth. It is sometimes stated in popular works on zoology that the worm picks out portions of leaves, grass, &c., and devours them; but this is quite a mistake—the earthworm lives upon earth. It must not be supposed that it assimilates the mineral constituents of the soil; its gastric and biliary secretions dissolve the decomposing animal and vegetable matters which are invariably contained in rich soil, and it is these which are assimilated. The earthworm could not live upon earth that had been burnt and deprived of its organic constituents. In a similar way the arenicola, or lung-worm, which lives in the sands exposed by the action of the tide, gorges itself with that substance, and extracts the matters which it contains fit for nutriment. More frequently, however, the "lug" lives in the rich clays of creeks and saltings which abound in animal and vegetable matters. It is worthy of observation that a very large quantity of earth or sand, as the case may be, has to be gorged before any appreciable amount of nutriment is extracted; at the same time the swallowing of earth is an assistance to the worm as it burrows in the ground, inasmuch as large quantities of material are thereby removed from its path and ejected behind. The appearance of those curious little masses of digested earth on the surface is thus caused, by means of which the earthworm effects such wonderful changes on the surface of the ground, turning up the earth, burying the stones, and producing a fresh and fertile soil where formerly was a barren waste. The mode in which the earthworm swallows the earth is somewhat curious: its pharynx is extremely muscular, and provided with an internal muscular tunic, which acts within like the piston of an air-pump; anything to which the mouth is applied is thus sucked in and passed on by the action of the muscular walls of