Part 5

Following the Silurian came the Devonian, which is called the age of fishes. In no time in the world's history have fishes been so large and so abundant as during this age. They outclassed in every respect all other animals. The same general types flourished as those which existed in the latter part of the Silurian. There were more species and more individuals and some grew to an enormous size. Fishes ruled the Devonian seas. The crustaceans, such as trilobites which greatly predominated during the Silurian age, diminished greatly during the Devonian. In the struggle for existence they decreased in size and in numbers, and were obliged to seek safety in less favorable places. The Devonian fishes were largely sharks and ganoids, especially the latter. These were covered, with hard, enamel-coated scales or bony plates. Some were short and heavy and entirely encased in a covering of large bony plates. They were evidently anything but pretty and their movements in the water must have been extremely awkward. Others were formed much after our own ideas of fishes. These bore much resemblance to our garpikes, the lung fish of the Nile and the lung fish of Australia, and the worthless dog fish of our own fresh waters. Anglers and fishermen all despise these fishes now, yet in Devonian times the fishes most nearly like them were evidently the most handsome and graceful of all fishes then living. It appears as if fishes in those days did not fight each other. They found abundant sea room and plenty of food in the form of invertebrates. Of course it is quite probable that many fish-like animals existed at this time, but possessing no hard parts and were not preserved as fossils; these could not become at all important for the sea was too full of large animals of all classes which were so well protected with a coat of mail and so hostile that those less favorably situated could not exist in any great numbers. At the close of the Devonian many changes took place. The rocks of this formation, which now form a portion of the earth's surface, rose out of the water, the land area thus considerably increased, the seasons, such as they were then, became more marked; many inland seas were formed. These changes were more or less gradual, but not so much so that the fishes living then could not suit themselves to the new conditions. Those fishes which had flourished for generations had become accustomed to easy living and certain fixed ways, could not adapt themselves to changing conditions, and so became extinct. The Pteraspids, the earliest forms to appear; the Pterichthys, in fact, all forms which bear any resemblance to our present lampreys, or which may prove a close relative of the earlier ganoids, became extinct at close of the Devonian. The early Chimeras which flourished from close of Silurian also became extinct. Many ganoids became extinct, but other ganoids came into existence to take their places. The ganoids most nearly like our modern sturgeons increased during the last of the Devonian and retained their prominence to the close of the Carboniferous. The slow-moving, heavily plated ganoids passed away. They ruled during the Devonian age, but could not suit themselves to the new conditions at beginning of the Carboniferous. While fishes were numerous and large in the Devonian, throughout the Carboniferous they began to decline. By this time the land area had much increased, land plants became very abundant, there were immense forests of tropical vegetation, great swamps and peat bogs--all of which later sank below sea level--became covered up and changed into coal. Immense lizards lived in these forests and along the sea shores; these were the first land animals. At the close of the Carboniferous great changes took place; greater changes than at any time since the close of the Archaean. So marked were the changes at this time that it marks a new era in the geological history of the earth. All preceding the close of the Carboniferous is regarded as ancient geology; all since then as modern geology. It was at this time that plants and animals were represented by new forms more like those now living. The geological age following the Carboniferous is the Triassic. With this age began our modern sharks and fishes. They did not become abundant until the Jurassic and Cretaceous. All of the earlier sharks had strong spines in front of each dorsal fin and broad teeth made for crushing. One form of these known as Cestracionts were very abundant till the end of the Cretaceous. In the early Triassic they began to decline and the sharks, with pointed teeth, increased. These sharks, with pointed teeth, but rounded on the edges, commenced back in the Carboniferous. During the Triassic the sharks, with lancet-shaped teeth, such as are now possessed by nearly all our sharks, commenced in small numbers. One of the important differences between the ganoids and the teleosts or true fishes is in the tail vertebrae. In the ganoids the tail vertebrae decrease gradually in size and curve upwards in the upper lobe of the tail. In the teleosts the tail vertebrae ends a short distance in front of ends of the middle fin rays of the tail fin. In the ganoids the upper lobe of the tail fin is the largest. In the teleosts both lobes are nearly the same size. The tail of the ganoid fish is called heterocercal, that of our modern or teleost fishes is homocercal. The tail of all early ganoids was strongly heterocercal. In the Triassic and Jurassic its lobes in many cases became nearly equal, approaching the homocercal tail. The tails of all sharks are heterocercal, of all modern fishes it is homocercal except in a few families, as the cod and related fishes, it is Isocercal; that is, the vertebrae decrease in size, but do not form an upward curve. So far as we know the Shad family is the first of our teleosts or true fishes to appear, and these were quite abundant in the early part of the Triassic.

The rays, fish-like animals much like Sharks, but with the body and fins flattened or spread out in a broad flat disc, appeared in the Jurassic. The Chimeras, so abundant in the Devonian and which died out apparently at the close of the Devonian, also reappeared at the beginning of the Jurassic. These did not belong to the same families as did the more ancient Chimeras. The Chimeras no doubt flourished in the Carboniferous and Triassic, but migrated to some portion of the sea where now perhaps their remains lie buried in rocks below the bottom of the sea. Their survivors, which were able to modify their structure and habits to become suited to new conditions, returned in modified forms in the Jurassic, where in time their remains come to the surface as fossils.

At the end of the Cretaceous or beginning of the Tertiary we find all of our modern types of sharks and all of the important orders of teleosts. The sturgeons and ganoids decreased throughout the Tertiary or Quaternary until at present we have but few living species. The sturgeons are the more abundant. Of the large group of Ganoids so abundant during all these geological ages but few forms are living to-day. These are the Ceratodus, lung fish of Australia; the Polypterus of the Nile, the Protopterus of Western Africa, the Dogfish and the three Garpike of North America. These few species are but the remnants of a once large and extensive group of fishes.

In the study of fishes we notice that some are highly specialized so far as their structures are concerned; the teeth of some become especially fitted for a peculiar kind of food, and as a result quite unfit for any other kind. Some, to be protected from their enemies, develop a heavy armor, which only retards their activity. Other fishes are more generalized; that is, are of medium size, omnivorous habits, are not hampered in their movements by a too heavy coat of mail, etc. When any change of conditions came to modify their habits of living the specialized were always the first to disappear. Being particularly fitted for one mode of life made them all the more unfitted for any other, and so when conditions changed they perished. All of our modern fishes except the few ganoids are more or less specialized. The trout lives in cool running water and some varieties can live in no other, while some fishes have become accustomed to warm, stagnant water and cannot live with the trout. What is true in this respect of fishes is true of land animals as well. The large, ponderous, slow-moving reptiles of the Triassic, Jurassic and the Cretaceous, and the large mammals of the Tertiary and Quarternary could not exist except under the peculiar conditions of that time, and sooner or later had to give way to the smaller, more active and more resourceful animals of their class.

In tracing the history of fishes from their earliest existence to the present one is struck with the myriad forms he finds. It would seem that all possible effort was made by them to modify their structure to suit their environment; when this changed all their efforts came to naught, and they were destined to give way to the more favored kinds. Seth E. Meek.

THE DEEP.

There's beauty in the deep-- The wave is bluer than the sky; And, though the light shine bright on high, More softly do the sea-gems glow That sparkle in the depths below; The rainbow's tints are only made When on the waters they are laid, And sun and moon most sweetly shine Upon the ocean's level brine. There's beauty in the deep.

There's music in the deep-- It is not in the surf's rough roar, Nor in the whispering, shelly shore-- They are but earthly sounds, that tell How little of the sea-nymph's shell, That sends its loud, clear note abroad, Or winds its softness through the flood, Echoes through groves with coral gay, And dies, on spongy banks, away. There's music in the deep.

There's quiet in the deep-- Above let tides and tempests rave, And earth-born whirlwinds wake the wave; Above let care and fear contend, With sin and sorrow to the end. Here, far beneath the tainted foam, That frets above our peaceful home, We dream in joy, and wake in love, Nor know the rage that yells above. There's quiet in the deep. John G. C. Brainard.

THE AMERICAN REDSTART.

(_Setophaga ruticilla._)

Contemporaneous with the blossoming out of the wild plum, the early Richmond cherry and a rich and diversified profusion of woodland flowers, perhaps better exemplified on this occasion by such interesting types as the little Claytonia, or spring-beauty, the rue-anemone and the trilliums, both T. erectum and grandiflorum, with perhaps a few belated blossoms of the hepatica, is the advent of this interesting little bird among us, which here in Northeastern Illinois usually plans its arrival somewhere near the closing days of the first week in May.

Its generic name, Setophaga, interpreted into plainer English, means a devourer of insects, and, were we to select from among the large and varied assortment of birds comprising the bulk of our warbler hosts a form most elegant and expressive of gayety, sprightliness, and, in a measure, frivolity, we could not go far wrong in determining upon this species so easily outclassing all others as the most brilliantly colored member of that numerously large and interesting family, the Mniotiltidae.

At first a creeper and sharp-eyed inspector of hidden crannies, we afterwards discern no less in him, and upon the slightest provocation, a tyrant on the wing, thereby proving a general adaptability to and utility in his calling at all stages of the game--a constant warfare directed against the insect horde to which he devotes himself most assiduously at all times, and it is really astonishing the amount of the minute forms of insect life these little birds will consume. So then, what at first may appear to us as clever acts of trifling weight will, upon closer inspection, prove carefully executed movements planned and carried out with the greatest precision.

Among ornithologists we find it classed as an interesting member of the group of fly-catching warblers. Equally suggestive to the mind of the writer would be the name of the fan-tailed warbler, derived from its well-known habit of carrying the tail slightly elevated and partly spread.

To those who may be on the lookout for just such marked characteristics among our birds this one feature alone will serve as an excellent index in determining its proper identification.

The plainer and grayer markings of the female and immature birds may differ very considerably from the more pronounced black and white, orange-red and salmon-colored blotches of the adult male, but never so strikingly manifesting themselves in the markings of the tail which in either case may appear to the casual observer as quite similar.

Yet if we examine them more critically we will discover that they are distinctly different, the salmon-red and black-tipped feathers of the male bird being replaced by a paler reddish-yellow and grayer-tipped arrangement in the case of the female. Young males have the darker markings of the tail feathers very similar to those of the adult birds, which we are told do not take on the complete dress until the third year. But the habit of constantly flitting the tail in fan-like motions is peculiar alike to all phases of this bird's plumage and above all other characters serves as the greatest aid in naming it.

The very young, or nestling dress, of which little or nothing seems to have been written, bears a partial resemblance to that of the female bird, excepting that the wings are crossed by two yellowish bands, caused by the lighter tippings of the outer coverts. The yellow breast spots of the female are also wanting in this dress.

For further particulars the reader is kindly referred to the colored plate accompanying this article.

Like the robin red-breasts, the name of the Redstart seems to have been brought to America by the earlier settlers who were ever on the watch for familiar objects to remind them of former days, and, as in the case of the example just cited, wrongfully ascribed by them to a far different bird. An analogy, however, exists in the coloration of the European and American birds justifying in a measure the reason for so naming it.

We are told, in Newton's Dictionary of Birds, that the Redstart, the Ruticilla phoenicurus of most ornithologists, is well known in Great Britain, where it is also called the Fire-tail, from the word "start" which in the original Anglo-Saxon "steort," means tail. But the English bird is very different from ours throughout, a marked distinction being its peculiarity of habit in seeking out for a nesting site a hole in a tree or ruined building.

Our bird, contrary to all this, more correctly builds its nest out of doors, usually selecting the upright forks of some tall shrub or small tree and placing therein a neat, compact structure, in which four or five light-colored eggs are deposited that in their spotted appearance and blotching of various shades of brown resemble very closely the eggs of the common yellow warbler (Dendroica aestiva).

But for all this, however, it repairs to the shadier depths of the woods while the yellow warbler on the other hand seeks out the more tangled thickets and willow copses.

The song of the Redstart, too, bears in a striking degree a very close resemblance to that of this same yellow warbler, though, as in the case of the nest, the localities frequented by it serve readily in making a distinction. "In general tone and quality," as Prof. Lynds Jones has remarked in No. 30 of the Wilson Bulletin, "Warbler Songs," "there is a strong resemblance to the Yellow, but the range of variation is greater and the song distinctly belongs to the 'ringing aisles' of the woods." "The common utterance can be recalled by che, che, che, che--pa, the last syllable abruptly falling and weakening." "A soft song is like wee-see, wee-see-wee, with a suggestion at least of a lower pitch for the last syllable."

The range of the American Redstart is quite extended, including, as we may say, all of North America, though it is very rare and irregular in the States west of the Sierras. It is said to breed from Kansas northward.

Tabulated observations compiled by the writer at Glen Ellyn, Illinois, during the past seven years, show that the southward movement of the Redstart commences about the end of the first week in August; the first part of September finds them common, after which their numbers gradually wane, the last of the month, or the first few days in October, witnessing its final departure. Benjamin True Gault.

THE FLYING FISH.

All animals are provided with some means of protection from the attacks of their enemies and with ways of escaping from any object which they may fear. The means furnished to the Flying Fishes is one of the most unique and interesting.

To escape the larger fishes that prey upon them, or when frightened by a passing vessel, these fishes will rise from the surface of the water and with distended but quiet fins pass over a distance of several feet. They have been known to rise to a height of twelve or more feet and fly for one hundred or more yards, although the height and distance traveled is usually much less. This power of flight is due to the great development of the breast (pectoral) fins, situated on the sides of the body near the head.

Some writers have stated that these fishes left the water for the purpose of catching insect food and that they had the power of regulating their flight by the movement of their fins. The best authorities, however, claim that they do not possess the power of changing the direction, velocity, or altitude of their flight and the position of the fins is not voluntarily changed, and that their object in leaving the water is not for food.

They rise without reference to the direction of the wind or waves, and frequently, when their course is at an angle with the wind, the direction of their flight may be changed by the air currents or by contact with the waves. The direction is also modified, when passing close to the water, by immersing the tail fin and moving it with a rudder like motion.

There are two groups of Flying Fishes, both natives of tropical and sub-tropical seas. In one of the groups there are less than five species, while classed under the other there are fifty or more.

EDITOR'S NOTE.

On account of inaccuracies in the report of Mr. Chapman's lecture, which was quoted in the June number of this Magazine, it is only due to Mr. Chapman that we publish the following letter received from him:

TO THE EDITOR OF BIRDS AND NATURE:

_Dear Sir_:--In the June issue of your magazine there appeared an alleged abstract from a lecture by me on the "Structure and Habits of Birds," which so abounds in errors that I beg you will permit me to state that the matter published was a newspaper report, for which I am in no way responsible. Yours respectfully, FRANK M. CHAPMAN.

+----------------------------------------------------------------- + | Transcriber's Note: | | | | Minor typographical errors have been corrected without note. | | | | Punctuation and spelling were made consistent when a predominant | | form was found in this book; otherwise they were not changed. | | | | Ambiguous hyphens at the ends of lines were retained. | | | | Italicized words are surrounded by underline characters, | | _like this_. | | | | The Contents table was added by the transcriber. | +------------------------------------------------------------------+