IN TOUCH WITH NATURE

Otago Witness, Issue 3671, 22 July 1924, Page 6

IN TOUCH WITH NATURE

A MYSTERY OF ANCIENT LIFE. (By J. Dbtjmmokd, F.LS., F.Z.ia.. A Nelson resident who spent a week in the Mount Arthur district has sent a fragment of the remains of a creature that represented the most prolific type of animal life in Palaeozoic seas. He found it near a creek on one of the mountain slopes. This trilobite may have lived when insects had appeared on the land and fishes in the sea, but it was before the days of amphibians, reptiles, birds and mammals. The mystery of the trilobites’ origin is as great as the mystery of their extinction, about the end of the Palaeozoic Era. Their history, dimly legible in the rocks, shows that they resembled woodlice in appearance. Their title comes from three distinct lobes in their ornamented bodies, the middle one being much narrower than the side lobes. Until recently only the hard parts of their backs and heads had been known, but particularly good specimens found in Connecticut show that they had appendages on the under surface. The front pair were whip-like, and, apparently Were used as antennae. Others were used for crawling, and others, fringed with bristles or small plates, may have been used for swimming. Attached to the head, there was an arrangement for biting food, which passed into the mouth. The bodies had many points, and were protected by a head-shield and tail-shield. Trilobites had compound eyes, like tho

eyes of a house-fly. Some of them had i very large and prominent eyes.; others had j very small eyes; others were absolutely j eyeless. Some had the faculty of rolling ! up into a ball, like wood-lice. Their re- j mains are found in limestones, mudstones, and sandstones of the older sedimentary rocks. Most of the remains are found in deposits laid down in shallow water. It is believed that some trilobites pushed their way into the deep waters and fed on delicate, tiny creatures that rained down from above. The shallow water trilobites, probably, crawled over the soft, oozy bed of the sea, and fed on worms and other organisms there. Their development from the juvenile stage to the adult stage was marked by the addition of segments of the body during moults.

The character of their structure seems to show that, on the theory of evolution, their origin was immeasurably distant from the earliest time to which they can be traced at present. Their superficial re-

semblance to woodlice and other crustaceans gave rise to a belief that they belonged to that group, but the character of their appendages has led zoologists to link them up with the spiders, scorpions, and mites. When the Challenger went on its notable scientific expeditions many years ago, some zoologists on board expected to dredge living trilobites from the sea-floor in great deaths. These faint hopes were not realisd, and there is no doubt now that the trilobite type is as dead as the proverbial door-nail. The amazing abundance of trilobites at one time in the world’s history is shown uy the fact that, even from their fragmentary remains, some 2000 species have been Identified. In New Zealand they have been

recorded from Silurian rocks in the Mount Arthur district, - *Lanky Gully (Reefton), and near Thompson’s Creek (Patarau). Doubtless they have been found in other parts of the dominion, but have not been recorded

A graphic description of a scene in the middle of the Palaeozoic Era, when t-e trilobites experienced their golden age, given by Captain F. W. Hutton, a New Zealand palaeontologis : —“ if a human spectator could have stood on the shore at that time he probably would have seen no animal life. The rocks below low-water mark were covered with delicate red and brown seaweeds, and the ocean between tide-marks, then, as now, was girdled with a belt of vivid green : but all the land above was brown and barren, without even a moss or lichen on it. On the sands at his feet might he _a dead jellyfish or a trilobite, or a delicate transparent shell thrown up by the waves ; but they would be seen rarely ; and the great ocean, although swarming with minute life, would seem, to the naked eye, tenantless.”

One theory of the cause of the trilobites’ disappearance is that, owing to great differentiation, they have lost their original energy, and gradually decreased in “numbers until utter extinction overtook them. Another theory was supplied by Captain Huton, on the following lines: As trilobites lived on the bottom of the ocean, where the temperature is uniform, we cannot invoke a change of climate as the cause of extinction ; and there does not appear to be any group of creatures that could be successful competitors with them for then.' food,

as we know that they fed on mud, which, no doubt, contained many organic particles. We must have recourse to predaceous foes. This reasoning is much strengthened by the fact that later trilobites learnt how to defend themselves by rolling themselves up, which earlier trilobites, of the Cambrian Period, could not do. The earliest powerful predaceous creatures we know were the ground cephalopods. The decline of trilobites coincides in time with the expansion of the members of the nautilus group. These ravenous cephalopods, precursors of our gigantic cuttle-fish, were the earliest rovers of the sea. Some lived near the surface. Others sank to the bottom, where the inoffensive trilobites had reigned for ages undisturbed quietly sucking mud. The ruthless intruders turned the trilobites over and tore out their insides, in spite of their attempts to defend themselves by each one rolling up into a ball.

Observations of the habits of the shipborer, a beetle that has been introduced into New Zealand, from America, apparently. show that both sexes are sexually mature wdien they emerge from their chrysalis stage, which is passed in small tunnels in wood. The ripe eggs accunn. late in a cup-shaped organ possessed by the female. Her ovipositor, by which she deposits the eggs in the wood, is about the same size as herself, when _it is ex traded. When the ovipositor is in repose, it consists of two sheaths, and it seems to be telescopic in structure. These beetles, Lyctus brunneus, and their cousins, Lyctus linearis, are not plentiful in New Zealand at present.

In June, 1898, when about half way between New Zealand and Fiji, Mr D. H. M'Kenzie, Stanley avenue, Milford, Takapuna, saw a flying fish, 19 inches long, that had gone on to the deck of the" Miowera. He was told by Captain Hemmings that the deck was 32ft above the water-line. The sea was calm. Mr M'Kenzie believes that flying fish can go through the air for 200 yards. The habits of an interesting New Zealand fuchsia are dealt with in a letter from Miss E. I>. C. Whibley, Onga-onga, Waipawa, Hawke’s Bay. “Itis a beautiful creeping konini,” she writes. “ It will grow anywhere, and it spreads rapidly in sandy soil, but I have not been able to discover its natural habitat. It has a small heart-shaped leaf, and a flower like the flower of the tree konini. but usually all one colour, the calyx a pale greenish yellow, shading to dark blue. Its flower," unlike the flower of the tree konini, is erect, and the cup is filled with sweet, rich honey. The greatest beauty of this plant is in its berries. These", which grow to the size of o-ooseberries, when ripe are scarlet. It is a lovely pot-plant, but, as the roots grow rapidly, it soon becomes pot-bound. I have searched for the plant in the bush near Westport, and around the Waitomo Caves, and in Hawke’s Bay, b.fc unsucI cessEully. The beauty of the creeping fuchsia" is much greater than the beauty of any other native creeper, and it is regrettable that, more New Zealanders are not given opportunities to see it.” Miss Whibley should have looked for the creeping "fuchsia—Fuchsia procumbens, officially—in sandy and rocky places near the sea, not in the bush, and in the North Island only. This slender, much-branched, prostrate, trailing shrub, localised in habitats, is one of the gifts with which Nature has favoured the North Island to the exclusion of the South Island. It often is seen in gardens and greenhouses in both islands with the title " Fuchsia kirkii, given it by gardeners. Mr R. M. Laing, Christchurch, states that, although it lacks the graceful pendulous flower-stalks that enhance the beauty of commoner species of fuchsia, it is a very dainty little species, and that the sharp contrast between the waxy yellow of the calyx and the intense pure blue of the pollen would make it noticeable anywhere. Tuis and bcllbii-L are seen sometimes with their heads coloured by the bright blue pollen of this fuchsia, and of New Zealand’s two other species. The

tree fuchsia, Fuchsia excortieata, is one of the best-known plants of this dominion. The third New Zealand species. Fuchsia colensoi, a small shrub, _ with long, straggling branches, a native of both islands, is the species, probably, that Miss Whibley refers to when she writes: “I found another plant, which may be more correctly termed the climbing fuchsia ; its berry is small and black.” The creeping fuchsia is the only creeping species with erect flowers, but all the New Zealand species have bright blue pollen, which is very viscid. Sixty species of f ichsias are known. All except the three New Zealand sreeies are natives of America from Mexico to Fuegia. The fuchsias link two countries on opposite sides of the world, and supply circumstantial evidence that, in the dim, remote past, there was land connection between them. As -stated previously in this column, this lovely family is dedicated to Mr Fox—in English—an enviable Sixteenth Century German botaist who. amongst other things, espoused the doctrines of the Reformation, and named the fox-glove and its allies Digitalis. ____________ - ;