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If we may try and rebuild this vanished beast of prey from conjecture, aided by collateral evidence, we should consider it an elongated, flexible form, developed from some swimming worm-like ancestor, perhaps like the Ascidian embryo, stiffened internally by a cord of firm flesh extending lengthwise through the body, and moving not by cilia, but by the aid of fleshy side flaps, the progenitors of the fin. We conjecture it to have been, in short, the early stage of the fish, a creature perhaps of considerable size and strength, due to the abundance of easily obtained food, but as destitute of hard parts and as little likely to be fossilized as Amphioxus.
We may offer this conjecture with some safety, for it is not long before we come upon actual traces of fish, and of a degree of development which indicates a long preceding stage of evolution. In fact, the fish in time appears to have been forced to put on armor, as its prey had earlier done. Internicine war began in the fish tribe itself. A wide specific variation arose, with great differences in size and strength, the stronger attacked the weaker species, and eventually two distinct types of fish appeared, the Elasmobranch and the Ganoid; the former, represented to us by the modern sharks, being much the most powerful and voracious, and holding the empire of the open seas, while the latter dwelt in shallower waters. The Ganoids, preying on the bottom forms, become themselves the prey of their strong and active kindred, and, as a result, the evolutionary process just described was resumed. The weaker fish put on armor, in many cases heavy and cumbrous, a dense bony covering which must have greatly reduced their nimbleness, but which safety imperatively demanded. It is these armored forms that first appear to us as vertebrate fossils; the first fish, as the first mollusk or crinoid known to us, being the resultant of a very long course of development. As regards the Elasmobranchs, they, too, became in a measure protected, though not sufficiently to indicate any very active warfare among themselves.
There is little more which we can say in this connection. The story of the evolution of life bears an analogy worth mentioning to that of the development of arms of offense and de
fense among men. After thousands of years of war with unarmored bodies, men began to use defensive armor, the body becoming more and more covered, until it was completely clothed in iron mail, and became rigid and sluggish. In the subsequent period offensive weapons became able to pierce this iron covering, and it was finally thrown aside as cumbrous and useless. A similar process is now going on in the case of war vessels, they being clad in heavy armor, which may yet be rendered useless by the development of cannon of superior piercing powers, and be discarded in favor of the light and nimble unarmored ship.
The analogy to animal evolution in this is singularly close. After long ages of active warfare between naked animals, defensive armor was assumed by nearly every type of life, except the lowest, highly prolific forms, and the highest, which had no foes to fear. But the powers of offense grew also, and in time the employment of armor ceased, as no longer available, its last important instance being that of the ganoid fishes. The later fish reduced their armor to thin scales, and gained speed and flexibility in proportion, while in land animals armor was seldom assumed. In several instances creatures have gone back to the old idea, as in the armadillo, the porcupine, the turtle, etc., but the thinly clad, agile form has become the rule, armor no longer yielding the benefit that was derived from it in the days of weak powers of offense. This result is a fortunate one, since with increase of agility mental quickness has come into play, the result being a development of the mind in place of the old development that was almost wholly confined to the body. In the highest form of all, that of man, physical variation has almost ceased, in consequence of the superior activity of mental evolution.
In conclusion it must be admitted that there are certain formations in nature which seem to militate against the argument here advanced. I have already spoken of the much questioned Eozoon canadense. In addition there are the beds of limestone and graphite in the Laurentian formation. But these prove too much for the advocates of their organic origin. If so large a fossil as Eozoon had appeared so early, the subse
quent barrenness of the rocks would be incomprehensible. And had coral animals and large plants capable of producing such masses of limestone and graphite existed so early, the absence of any fossils earlier than the Cambrian would be inexplicable. It is acknowledged, however, that such formations might have been produced by inorganic agencies, and the facts strongly indicate that such was their origin, and that fossils began to be preserved very shortly after the power in animals to secrete hard skeletons appeared.
BIRDS OF NEW GUINEA (FLY CATCHERS AND
BY G. S. MEAD.
(Continued from page 195.)
The Thickheads (Pachycephala) are of many species and scattered widely over the Archipelago. Many have come under trained observation only during recent years. Probably many more await discovery.
Pachycephalopsis poliosoma, Gray Thickhead, was discovered by Mr. A. Goldie in Southeastern New Guinea, and owing to its distinctive coloration was classed as a new genus. It is really one of a group of birds which might form a subgenus and is accordingly so divided by Mr. Gadow. Above the general color is dark gray, almost brown, with the head still darker. The square, rather short tail is also dull of hue. Beneath is dull gray, lighter on the abdomen and tail coverts, whitish to white on the jugulum, throat, chin and side face. It is a pretty, soft colored little bird about 6 inches long, sufficiently numerous among the mountains of the Astrolabe range to be called common.
Pachycephala melanura ranges widely over Northern Australia and the Archipelago. The general color above is olivegreen; wing coverts, tail, head and an irregular band passing
over the head, neck and breast, black and glossy black. The under parts, with a broken collar about the neck, are a warm light yellow. Throat a pure white. Whitish lines the under side of the wings and tail. Bill and feet black. The female lacks the vivid coloring of the male, being brownish where he is a jet black, buff or whitish where he is a bright gold. Length 7 inches.
Very like the above, but of reduced size, is Pachycephala schlegelii, whose total length is under 5.5 inches. The differences lie in the greater width of black band across the breast, in the line of black edging the wings, and the orange rufous on the abdomen. The female resembles the female of Pachycephala soror, found also among the Arfak Mountains. This bird is olivebrown above, wings and head darker. The under surface is a bright yellow, omitting the grayish wings and dull thighs. Like her mate, the throat and chin are white. The male P. soror is unmarked by the yellow nuchal collar but is not without the black crescent. A bright yellow covers the breast and abdomen. The head is black, the tail dusky.
Total length about 6 inches.
There are several other species of Pachycephala resident in Papua, almost all bearing a greater or less resemblance to each other. Among these may be mentioned without detailed description, P. hyperythra from Southeastern New Guinea whose under parts are of the warm reddish color that gives it its specific name.
P. albispecularis, from the Arfak region, is another speciesa somewhat larger bird than its kind, gray and dark brown in general coloring with white markings on the wings.
Still another is P. griseiceps or virescens, with local differences, a bird of the average length, somewhat diversified plumage and a mottled head.
Smaller than the foregoing but with throat and chest crescent more distinctly outlined, is P. leucogaster, collected in the Motu country. P. leucostigma, from the northeast, is considerably mottled, with much rufous on the under parts, the usual white in this instance somewhat discolored, on the throat, and much streaked on the mantle.
Pachycephala fortis has its habitat in the Astrolabe Mountains, though found probably elsewhere in New Guinea. Its total length is nearly 7 inches, colored almost entirely above dark olive, below ashy gray. The head and mantle are dark gray, the tail dusky, the back and wings greenish olive. On the face are gray shadings. White prevails on the abdomen, passing into yellow. The under wings do not differ from the uniform cloudiness but are, if anything, eyen duller than the body.
Pachycare flavogrisea, set apart from Pachycephala, is colored a bluegray above, somewhat varied on the tail and wings by black or white edgings, while the under parts are a “deep, shining yellow, the yellow on the forehead and the sides of the head and neck being separated from the bluegray of the head by a broad dark stripe." Total length 4.5 inches.
If we look for those attractive little birds-the Titmice-in New Guinea, we shall find very few, if any, specimens. One is mentioned in the books, viz., Xerophila leucopsis, an Australian species, abundant in Queensland but not so numerous in Southern Papua. The little bird in question has a length of 4 inches. Its general color is brown, ashy above, whitish and yellowish beneath. Along the tail, neck and head the brown is positive; this is true also of the under wings; elsewhere, however, the colors are pale and indistinct, shading off gradually, as on the sides and breast, into a clouded white.
Several species and subspecies of the genus Cracticus range between Australia and New Guinea. These are Lanidine birds of good size, strong of beak, black, white or gray of color.
Cracticus quoyi, a typical representative, is one of these distributed pretty generally over North Australia and Southern Papua. It is almost entirely black and blueblack, the only variation being in the shading and lustre. The length is about 14 inches. Sexes alike.
Cracticus cassicus or personatus is more peculiarly insular, being confined chiefly to New Guinea and its islands.
The bird is strikingly conspicuous in its contrasted black and white. The former color covers the head and neck, throat and chest, upper wings and tail, excepting the two