Tadpoles are aquatic vertebrates.
Forbes drew attention to a certain community amongst birds and other vertebrates, invertebrates, and amongst plants, on all the lands stretching towards the south pole.
The scope of the anatomical part of the following article is a general account of the structure of birds (A y es) in so far as they, as a class, differ from other vertebrates, notably reptiles and mammals, whilst features especially characteristic, peculiar or unique, have been dwelt upon at greater length so far as space permitted.
Slonaker, " Comp. Study of the Area of Acute Vision in Vertebrates," Journ.
Goodrich that the vascular system and the coelom are in communication (as in vertebrates by means of the lymph system).
Similarly, among vertebrates the method of restoring past centres of origin, largely originating with Edward Forbes, has developed into a most distinct and important branch of historical work.
It is certainly a very striking fact that wherever we have been able to trace genetic series, either of invertebrates or vertebrates, in closely sequent geological horizons, or life zones, we find strong proof of evolution through extremely gradual mutation simultaneously affecting many parts of each organism, as set forth above.
Such decline is by no means a universal law of life, however, because among many of the continental vertebrates at least we observe extinctions repeatedly occurring during the expression of maximum variability.
Whereas among many ammonites and gastropods smooth ness of the shell, following upon an ornamental youthful Condition, is generally a symptom of decline, among many other invertebrates and vertebrates, as C. E.
Beecher (1856-1905) has pointed out (1898), many animals possessing hard parts tend toward the close of their racial history to produce a superfluity of dead matter, which accumulates in the form of spines among invertebrates, and of horns among the land vertebrates, reaching a maximum when the animals are really on the down-grade of development.
Trypanosomes are harboured by members of all the chief classes of vertebrates with the exception of cyclostomes.
He has shown that, as in the Crossopterygian and Chondrostean ganoid fishes, there co., are two clavicular elements on each side; the lower corresponds to the clavicle of reptiles and higher vertebrates, whilst the upper corresponds to the clavicle of teleostean fishes, and has been named by him "cleithrum."
Gill, "On the Derivation of the Pectoral Member in Terrestrial Vertebrates," Rep. Brit.
One of the functions of this peculiar muscle (which is similarly developed in crocodiles, but absent, or not differentiated from the ilio-tibial and ilio-femoral mass, in other vertebrates) is that its contraction helps to close the second and third toes.
The fauna of Liberia is sufficiently peculiar, at any rate as regards vertebrates, to make it very nearly identical with a "district" or sub-province of the West African province, though in this case the Liberian "district" would not include the northernmost portions of the country and would overlap on the east and west into Sierra Leone and the French Ivory Coast.
The more complete replacements, such as the nephridia of the genital segment of Tubifex by a subsequently formed genital duct, may be compared with the succession of the nesonephros to the pronephros in vertebrates, and of the metanephros to the mesonephros in the higher vertebrates..
Recent discoveries of vertebrates are of the same significance, the most primitive fishes being traced to the Ordovician or base of the Silurian, 2 which proves that we shall discover more 2 Professor Bashford Dean doubts the fish characters of these Ordovic Rocky Mountain forms. Frech admits their fish character but considers the rocks infaulted Devonic.
For example, among the land vertebrates the feet (associated with the structure of the limbs and trunk) may take one of many lines of adaptation to different media or habitat, either aquatic, terrestrial, arboreal or aerial; while the teeth (associated with the structure of the skull and jaws) also may take one of many lines of adaptation to different kinds of food, whether herbivorous, insectivorous or carnivorous.
Because of the repetition of analogous physiographic and climatic conditions in regions widely separated both in time and in space, we discover that continental and local adaptive radiations result in the creation of analogous groups of radii among all the vertebrates and invertebrates.
The life of the land waters was also noteworthy, especially for the great deployment of what may be called the crustacean-ostracodermo-vertebrate group. The crustacea were represented by eurypterids, the ostracoderms by numerous strange, vertebrate-like forms (Cephalaspis, Gyathaspis, Trematopsis, Bothriolepss, &c.), and the vertebrates by a great variety of fishes, The land life of the period is represented more fully among the fossils than that of any preceding period.
It will be seen that the umbilical fissure (u) divides the organ into right and left halves, as in the lower vertebrates, but that the ventral part of each half is divided into a central and lateral lobe.
A list of all the fossils of the island known in 1895, but omitting the vertebrates above mentioned, included 1 For most of the information here given on the geology the writer is indebted ' to Captain Mouneyres, chef de services des mines, and the Rev. R.
Huxley, in his article on this subject in the ninth edition of the Encyclopaedia Britannica, for applying the name Amphibia to those lung-breathing, pentadactyle vertebrates which had been first severed from the Linnaean Amphibia by Alexandre Brongniart, under the name of Batrachia, have not met with universal acceptance.
However extraordinary it may appear, especially to those who bring the living forms only into focus, that opposition should still be made to Huxley's primary division of the vertebrates other than mammals into Sauropsida (birds and reptiles) and Ichthyopsida (batrachians and fishes), it is certain that recent discoveries in palaeontology have reduced the gap between batrachians and reptiles to such a minimum as to cause the greatest embarrassment in the attempt to draw a satisfactory line of separation between the two; on the other hand the hiatus between fishes and batrachians remains as wide as it was at the time Huxley's article Amphibia (Encyclopaedia Britannica, 9th ed.) was written.
Our knowledge of Devonian forms is still extremely meagre, the only certain proof of the existence of pentadactyle vertebrates at that period resting on the footprints discovered in Pennsylvania and described by O.
The members of this group are always carnivorous or parasitic, and prey upon both vertebrates and invertebrates.
Remains of extinct birds are, compared with those of other classes of vertebrates, exceedingly scarce, and these have been found in very few, widely separated countries.
Some of the scavengers, like the burying beetles, inter the bodies of small vertebrates to supply food for themselves and their larvae, or, like the "sacred" beetle of Egypt, collect for the same purpose stores of dung.
Of Vertebrates, ii.
From serving primitively as the essential organ of the cleft the tongue-bar may have undergone reduction and modification, becoming a secondary bar in Amphioxus, subordinate to the primary bars in size, vascularity and development; finally, in the craniate vertebrates it would then have completed its involution, the suggestion having been made that the tongue-bars are represented by the thymusprimordia.
An important nucleo-proteid is haemoglobulin or haemoglobin, the colouring matter of the red blood corpuscles of vertebrates; a related substance, haemocyanin, in which the iron of haemoglobin is replaced by copper, occurs in the blood of cephalopods and crayfish.
Sir Richard Owen, in his work on The Anatomy of Vertebrates, followed Latreille in dividing the Vertebrata into Haematotherma and Haematocrya, and adopted Leuckart's term of Dipnoa for the Amphibia.
The larvae usually live in Molluscs, the mature worm in vertebrates, and the immature but metamorphosed Trematode in either host and also in pelagic and littoral marine and fresh-water invertebrates.
Snakes are the most stationary of all vertebrates; as long as a locality affords them food and shelter they have no inducement to change it.
The Texas Cretaceous is notably rich in the fossil remains of an invertebrate fauna and in the vicinity of Waco Cretaceous fossils of vertebrates have been obtained.
The Bad Lands of the White river are also noted for their wealth of animal fossils, which have been found in such quantities as to cause geologists to believe that the vertebrates perished there in droves during a severe storm or flood.
His speculations on phylogeny, or the descent of invertebrates and vertebrates, were, however, most fantastic and bore no relation to palaeontological evidence.
As among the vertebrates, materials were accumulating rapidly for the great generalizations which were to follow in the third period.
Thus the recapitulation law, which had been built up independently from the observations and speculations on vertebrates by Lorenz Ofen (1779-1851), Johann Friedrich Meckel (1781-1833), St Hilaire, Karl Ernst von Baer (1;92-1876) and others, and had been applied (1842-1843) by Karl Vogt (1817-1895) and Agassiz, in their respective fields of observation, to comparison of individual stages with the adults of the same group in preceding geological periods, furnished the key to the determination of the ancestry of the invertebrates generally.
21), so that its fibres join the anterior faces of the nerve-end cells as in Vertebrates, instead of their posterior faces as in the cephalic eyes of Mollusca and Arthropoda; moreover, the lens is not a cuticular product but a cellular structure, which, again, is a feature of agreement with the Vertebrate FIG.
It must, however, be distinctly borne in mind that there is a fundamental difference between the eye of Vertebrates and of all other groups in the fact that in the Vertebrata the retinal body is itself a part of the central nervous system, and not a separate C E k e FIG.
Is present not only in the highest vertebrates - men, mammals,.
Durham, "Tyrosinases in the Skins of Pigmented Vertebrates," Proc. Roy.
In fact, among the remaining land vertebrates, only the black salamander (Salamandra atra) is exclusively alpine.
With the exception of the vertebrates, every one of the great classes of animals is represented in Cambrian rocks.
Willey, Amphioxus and the Ancestry of the Vertebrates (1894); "Remarks on some recent Work on the Protochorda," Quart.
The fauna has been explored in great detail both as regards the vertebrates and the invertebrates, and specialists will find the necessary bibliographical indications in Travaux geographiques en Finlande, published for the London Geographical Congress of 1895.
In habits the binturong is nocturnal and arboreal, inhabiting forests, and living on small vertebrates, worms, insects and fruits.
This progress consists in an increasing similarity of the living fauna, and, among the vertebrates especially, in their increasing resemblance to man."
In less highly integrated organisms, such as "cold-blooded" vertebrates, the point of death is less conspicuous, and when we carry our observations further down the scale of animal life, there ceases to be any salient phase in the slow transition from life to death.
In some of the lower vertebrates quinine reduces the activity of the spinal cord, but in the human species it appears to stimulate the nervous mechanism of the uterus under certain conditions, and it is therefore included under the class of oxytocic or ecbolic drugs.
From its occurrence in so many of the lower vertebrates, the entepicondylar foramen of the humerus, as it is called, is regarded by Dr E.
- That mammals have become differentiated from a lower type of vertebrates at least as early as the commencement of the Jurassic period is abundantly testified by the occurrence of the remains of small species in strata of that epoch, some of which are mentioned in the articles Marsupialia and Monotremata.
Fossils of both vertebrates and invertebrates are also common in the Permian and Jurassic formations.