The inference is almost irresistible that the law of gradual transformation through minute continuous change is by far the most universal; but many palaeontologists as well as zoologists and botanists hold a contrary opinion.
The eastern and western halves ale contrasted in climate-the former being moist and the latter dryand have been distinguished by some zoologists as distinct subregions.
It is interesting to observe that though deduced exclusively from the study of flowering plants, they are in substantial agreement with those now generally adopted by zoologists, and may therefore be presumed to be on the whole natural.
About eighty-five families are generally recognized; the difficulty that confronts the zoologists is the arrangement of these families in "superfamilies" or "sub-orders."
Brisson (1756), is still adopted by many zoologists, while others prefer the name Hexapoda, first used systematically in its modern sense by P. A.
In moths and certain saw-flies there is no rupture of the membranes; the Russian zoologists Tichomirov and Kovalevsky have described the growth of both amnion and embryonic ectoderm around the yolk, the embryo being thus completely enclosed until hatching time by both amnion and serosa.
Such a young insect is a larva - a term used by zoologists for young animals generally that are decidedly unlike their parents.
Some of those zoologists who look to Peripatus, or a similar worm-like form, as representing the direct ancestors of the Hexapoda have laid stress on a larva like the caterpillar of a moth or saw-fly as representing a primitive stage.
The travels of Le Vaillant in South Africa having been completed in 5785, his great Oiseaux d'Afrique began to appear in Paris in 1797; but it is hard to speak properly of this work, for several of the species described in it are certainly not, and never were in his time, inhabitants of that country, though he sometimes gives a long account of the circumstances under which he observed them.1° From travellers who employ themselves in collecting the animals of any distant country the zoologists who stay at home and study those of their own district, be it great or small, are really not so much divided as at first might appear.
It is almost certain that more than half the zoologists of the British Islands for many years past have been infected with their love of the study of Gilbert White; and it can hardly be supposed that his influence will cease.
Macleay indeed never pretended to a high position in this branch of science, his tastes lying in the direction of Entomology; but few of their countrymen knew more of birds than did Swainson and Vigors; and, while the latter, as editor for many years of the Zoological Journal, and the first secretary of the Zoological Society, has especial claims to the regard of all zoologists, so the former's indefatigable pursuit of Natural History, and conscientious labour in its behalf-among other ways by means of his graceful pencil-deserve to be remembered as a set-off against the injury he unwittingly caused.
For some time past rumours of a discovery of the highest interest had been agitating the minds of zoologists, for in 1861.
1 4 This peculiarity had led some zoologists to consider the struthious birds more nearly allied to the Mammalia than any others.
He also carried to a very extreme limit his views of nomenclature, which were certainly not in accordance with those held by most zoologists,, though this is a matter so trifling as to need no details in illustration.
In 1735 appeared the first edition of the Systema naturae of Linnaeus, in which the "Insecta" form a group equivalent to the Arthropoda of modern zoologists, and are divided into seven orders, whose names - Coleoptera, Diptera, Lepidoptera, &c., founded on the nature of the wings - have become firmly established.
Some zoologists, indeed, include in the same genus the South African thick-tailed hare, but by others this is separated as Pronolagus crassicaudatus.
Zoologists usually reckon but an hundred and seventy species in all."
Zoologists are familiar with many instances (fishes, crustaceans) in which the protective walls of a water-breathing organ or gill-apparatus become converted into an air-breathing organ or lung, but there is no other case known of the conversion of gill processes themselves into air-breathing plates.
In 1893, some years after the identification of the somites of Limulus with those of Scorpio, thus indicated, had been published, zoologists were startled by the discovery by a Japanese zoologist, Kishinouye (8), of a seventh prosomatic somite in the embryo of Limulus longispina.
Thus it was that the so-called " Natur-philosophen " of the last decade of the 18th century, and their successors in the first quarter of the 19th, found few adherents among the working zoologists and botanists.
The astonishing colours and grotesque forms of some animals and plants which the museum zoologists gravely described without comment were shown by these observers of living nature to have their significance in the economy of the organism possessing them; and a general doctrine was recognized, to the effect that no part or structure of an organism is without definite use and adaptation, being designed by the Creator for the benefit of the creature to which it belongs, or else for the benefit, amusement or instruction of his highest creature - man.
The effect of the Linnaean system upon the general conceptions of zoologists was no less marked than were its results in the way of stimulating the accumulation of accurately observed details.
His true greatness can only be estimated by a consideration of the fact that he was a great teacher not only of human and comparative anatomy and zoology but also of physiology, and that nearly all the most distinguished German zoologists and physiologists of the period 1850 to 1870 were his pupils and acknowledged his leadership. The most striking feature about Johann Miller's work, apart from the comprehensiveness of his point of view, in which he added to the anatomical and morphological ideas of Cuvier a consideration of physiology, embryology and microscopic structure, was the extraordinary accuracy, facility and completeness of his recorded observations.
Vaughan Thompson is a type of the marine zoologists, such as Dalyell, Michael Sars, P. J.
Many zoologists - prominent among them in Great Britain being Huxley - had been repelled by the airy fancies and assumptions of the " philosophical " morphologists.
The facts of the relationships of animals to one another, which had been treated as the outcome of an inscrutable law by most zoologists and glibly explained by the transcendental morphologists, were amongst the most powerful arguments in support of Darwin's theory, since they, together with all other vital phenomena, received a sufficient explanation through it.
Kolliker (Development of Cephalopods, 1844), Remak (Development of the Frog, 1850), and others had laid the foundations of this knowledge in isolated examples; but it was Kovalevsky, by his accounts of the development of Ascidians and of Amphioxus (1866), who really made zoologists see that a strict and complete cellular embryology of animals was as necessary and feasible a factor in the comprehension of their relationships as at the beginning of the century the coarse anatomy had been shown to be by Cuvier.
Pre-Darwinian zoologists had been aware of the class of facts thus interpreted by Fritz Muller, but the authoritative view on the subject had been that there is a parallelism between (a) the series of forms which occur in individual development, (b) the series of existing forms from lower to higher, and (c) the series of forms which succeed 'one another in the strata of the earth's crust, whilst an explanation of this parallelism was either not attempted, or was illusively offered in the shape of a doctrine of harmony of plan in creation.
One result of the introduction of the new conceptions dating from Darwin was a healthy reaction from that attitude of mind which led to the regarding of the classes and orders recognized by authoritative zoologists as sacred institutions which were beyond the criticism of ordinary men.
In the opinion of several zoologists it marks the tail-end and not the head-end of the worm.
So long ago as the year 1855, when the species was known to zoologists only by its skeleton, a gorilla was actually living in England.
Zoologists divide the earth into biological areas or regions, so both archaeologists and ethnologists may find it convenient to have in mind some such scheme of provinces as the following, partly after the dominant ethnic provinces.
Among the pioneers of this period were the vertebrate zoologists and comparative anatomists Peter Simon Pallas, Pieter Camper and Johann Friedrich Blumenbach.
The absolute agreement in the results independently obtained by these various investigators, the interpretation of individual development as the guide to phyletic development, the demonstration of continuous genetic series, each mutation falling into its proper place and all showing a definite direction, constitute contributions to biological philosophy of the first importance, which have been little known or appreciated by zoologists because of their publication in monographs of very special character.
MEDUSA, the name given by zoologists to the familiar marine animals known popularly as jelly-fishes; or, to be more accurate, to those jelly-fishes I in which the form of the body resembles that of an umbrella, bell or parachute.
Zoologists of the standing of Huxley, Claus and Leydig added to our knowledge of the anatomy and to the theory of their relations.
Foremost among those who between 1840 and 1880 laboured in this field are the French zoologists Henri Milne-Edwards° and Lacaze Duthiers, 10 to the latter of whom we owe the most accurate dissections and beautiful illustrations of a number of different types.
Of late years, however, zoologists have come to the conclusion that generic subdivisions of the Leporidae are advisable.
Their structure is similar to that of Trematodes, from which in the opinion of most zoologists they have been derived.
We give below that which seems to us to be the most satisfactory (based very largely on personal acquaintance with most parts of the range), considering, as in the case of the limits of the chain, only its topographical aspect, as it exists at the present day, while leaving it to geologists, botanists and zoologists to elaborate special divisions as required by these various sciences.
The two best-known species, so much alike in size, form, colour and habits that, although they are widely separated geographically, some zoologists question their specific distinction, are P. lutreola, the Norz or Sumpfotter (marsh-otter) of eastern Europe, and P. visors, the mink of North America.
Before leaving the Chlorophyceae, it should be mentioned that the genus Volvox has been included by some zoologists (Btitschli, for example) among Flagellata; on the other hand, certain green Flagellata, such as Euglena, are included by some botanists (for example, van Tieghem) among unicellular plants.
As is well known to zoologists, and as has been very lucidly set forth by Mdbius, the location of oyster banks is sharply defined by absolute physical conditions.
The fauna of the Tibetan Himalaya is essentially European or rather that of the northern half of the old continent, which region has by zoologists been termed Palaearctic. Among the characteristic animals may be named the yak, from which is reared a cross breed with the ordinary horned cattle of India, many wild sheep, and two antelopes, as well as the musk-deer; several hares and some burrowing animals, including pikas (Lagomys) and two or three species of marmot; certain arctic forms of carnivora - fox, wolf, lynx, ounce, marten and ermine; also wild asses.
In spite of the opinion of some distinguished zoologists to the contrary, it seems most probable that the separation of the sexes is in this case a secondary condition, derived from hermaphroditism through the intermediate stage represented by the species having complemental males.
It is plain that some eminent zoologists, regarding man as absolutely differing as to mind and spirit from any other animal, have had their discrimination of mere bodily differences unconsciously sharpened, and have been led to give differences, such as in the brain or even the foot of the apes and man, somewhat more importance than if they had merely distinguished two species of apes.
POLYP, the name given by zoologists to the form of animal especially characteristic of the subphylum Cnidaria of the Coelentera.
There have always been many zoologists prepared to ascribe an ancestral character to the holothurians.
Indeed, as it is, we are already partially acquainted with one of these early intermediate creatures (Tritylodon), which forms a kind of zoological shuttlecock, being, so to speak, hit from one group to another, and back again, by the various zoologists by whom its scanty remains have been studied.
In regard to tracheae the very natural tendency of zoologists has been until lately to consider them as having once developed and once only, and therefore to hold that a group " Tracheata " should be recognized, including all tracheate Arthropods.
The three known species constitute the genus Uacaria (or Cothurus) of zoologists, and are confined to the forests of Amazonia and the neighbourhood.
Linnaeus applied the Latin term Vermes to the modern zoological divisions Mollusca, Coelentera, Protozoa, Tunicata, Echinoderma (qq.v.), as well as to those forms which more modern zoologists have recognized as worms. As a matter of convenience the term Vermes or Vermidea is still employed, for instance in the International Catalogue of Zoological Literature and the Zoological Record, to cover a number of wormlike animals.
There are thus eight modifications of the horse-type at present existing, sufficiently distinct to be reckoned as species by most zoologists, and easily recognizable by their external characters.
Specimens were subsequently obtained from other parts of the neotropical region, and from South Africa and Australia, and the animal was variously assigned by the zoologists of the day to the Annelida and Myriapoda.
The Annelidan affinities are superficially indicated in so marked a manner by the thinness of the cuticle, the dermomuscular body-wall, the hollow appendages, that, as already stated, many of the earlier zoologists who examined Peripatus placed it among the segmented worms; and the discovery that there is some solid morphological basis for this determination constitutes one of the most interesting points of the recent work on the genus.