Henry Fairfield Osborn

Camarasaurus, Amphicoelias, and other sauropods of Cope

Introduction In 1902 the Cope Collection of Fossil Reptiles was presented to the American Museum of Natural History by President Morris K. Jesup. It included all of Cope’s types and other dinosaur material of Morrison age from the vicinity of Canyon City, Colorado. Several of these types antedated in definition Marsh’s types from beds of similar age. Cope’s references were full, but accompanied by few figures; Marsh’s came later and were adequately illustrated. Marsh also issued, in the publications of the United States Geological Survey, two more or less complete summaries of the characters of these animals, which were fully illustrated and widely distributed; consequently they became well established in the literature, while Cope’s are still unrecognized and imperfectly known. Our object has been to describe and determine as fully as possible Cope’s types, especially of the Opisthoccelia, the most important of which is that of Camarasaurus. This generic name antedates . . .

Trituberculy: A Review Dedicated to the Late Professor Cope

The morphology of the crowns of the mammalian teeth has sprung up practically as a new branch of study since Edward D. Cope and other paleontologists have demonstrated the unity of derivation of all the complex forms from the tritubercular type. The older works and ideas of Cuvier, Owen, Huxley and others are of comparatively little service now, for they treat the teeth of each order of mammals as of so many distinct types, whereas they must now be treated as modifications of one type. This new odoritography of the mammalia may be dated from the time when it was recognized that the crowns of the teeth of the Unguiculata and Ungulata, in the comprehensive Linnaean sense, are based upon a common type and are composed of homologous elements of similar origin, as developed by Cope, Osborn, Scott, Schlosser and others. It dates also from the new embryology of the teeth as studied by Leche, Kikenthal, Taeker, R6se, Woodward and others, with the revelations as to primitive form, number, and milk succession. But to fully establish the morphological branch in its new era we must first demonstrate the theory of a tritubercular

Reconsideration of the Evidence for a Common Dinosaur-Avian Stem in the Permian. Dinosaur Contributions, No. 4

THE relation of dinosaurs to birds has been one of the most attractive problems of comparative anatomy during the thirtyseven years which have elapsed since Gegenbaurs observation that the tibiotarsus of Compsognathus, one of the smallest carnivorous dinosaurs, closely resembles that of the bird. Since a number of new avian resemblances have recently been discovered among dinosaurs, it seems important to reconsider this much debated problem.

Evolution, phylogeny, and classification of the Mastodontoidea

Introduction In previous papers reasons have been given for dividing the Proboscidea into four main superfamilies, as follows: I. Mœritherioidea, typified by Mœritherium, Oligocene, North Africa. II. Dinotherioidea, typified by Dinotherium, Miocene and Pliocene, Eurasia. III. Mastodontoidea, typified by the bunomastodonts and the mastodonts, Africa, Eurasia, North and South America. IV. Elephantoidea, typified by the stegodonts, loxodonts, elephants, and mammoths, Africa, Eurasia, North America. As clearly pointed out in the second paper on this subject (Osborn, 1921. 514, pages 2–5), these four superfamilies are clearly distinguished from each other by profound differences in the adaptations of the cutting teeth, namely, the first and second pairs of superior and inferior incisors characteristic of all Proboscidea. The author is not prepared at present to add to what has been said in previous papers regarding the mœritheres and dinotheres. Species Continued observation of the types on which the species in all parts of . . .

Origin of Single Characters as Observed in Fossil and Living Animals and Plants

IN the last thirty years two biologies have been developing. The first is the biology of the garden, the seed pan, the incubator, and the breeding pen. The second is the biology of the field zoologist, of the field botanist, of the paleontologist. Inasmuch as one regards unnatural processes and the other regards natural processes it is small wonder that these biologies have become as far apart as two religions and have developed their sects and their dogmatists. Yet the actual facts assembled in these two biologies as distinguished from the opinions based thereupon can not be in the least discordant, for certainly there is only one system of law operating in the living world and there can be only one ultimate and final biology. In my Harvey lecture of 19122 the search for some unity between the observations in these two great fields of natural and experimental research met with some failure

Old and new standards of Pleistocene division in relation to the prehistory of man in Europe

I. Old and new Standards of Pleistocene Division INTRODUCTION A matter of supreme human interest in anthropology at the present time is the appearance of man in the successive stages of the geologic history of Eurasia and of Africa. The chief object of the present paper is to submit a summary and synthesis of the most recent interpretations in the European Quaternary, both in their bearing on the prehistory of man and as time standards of importance to students of American Pleistocene geology and physiography. The recent coordinations of Deperet have set a new basis of time division for the whole Quaternary. The researches of De Geer establish the past fifteen millennia. When combined they support, with certain modifications, the pioneer work of Penck and Brackner. This paper opens with a review of the progress of opinion from 1901 to 1921; it presents a precise statement of Deperet’s contributions of . . .

Recent results in the phylogeny of the Titanotheres

Recent discoveries have modified the author’s earlier opinions as to the lines of descent of the titanotheres and still further changes are anticipated with increase of knowledge of the connections between Upper Eocene, or Uinta, titanotheres and those of the Lower Oligocene, or White River. The main lines of division are indicated in the proportions of the limbs, whether cursorial, mediportal, or graviportal; the proportions of the skull, whether mesaticephalic, brachycephalic, or dolichocephalic; the development of fronto-nasal horns, whether accelerated or retarded; the molarization of the premolar teeth, whether accelerated or retarded; the presence or absence of incisor teeth; the abbreviate or elongate, the triangular or oval form of the fronto-nasal horns as developed in Oligocene times. With these criteria the various phyla may readily be distinguished as follows: AWind River titanotheres, face more elongate than cranium: Bridger

The Origin of the Mammalia

THE most important problems in vertebrate morphology at -the present time are the connections which once existed between the great vertebrate classes. As regards the three lower classes, the present state of opinion is as follows: The Amphibia are ,derived by Pollard, Cope, Dollo, and Baur from the ancient *crossopterygian fishes, an order represented by the modern Polypterus and Calamoicthys, the Dipnoi being regarded as a parallel rather than an ancestral line. The Reptilia, as repre.sented by their most primitive order with solid-roofed skulls (Cotylosauria, Cope, or Pareiasauria, Seeley), are believed to have sprung from that type of stegocephalian Amphibia which possessed rachitomous vertebrae, or with centra and intercentra. This division between reptiles and amphibians must have .occurred as far back as the base of the Permian, or even in the Upper Carboniferous, because in the Middle Permian we find several orders of highly specialized reptiles, namely, the Cotylo.sauria, Cope, Proganosauria, IBaur, Dicynodontia, Owen, and Theriodontia, Owen, highly specialized in the so-called Gom-

The Nine Principles of Evolution Revealed by Paleontology

IN honor of Darwin our first thought is that Natural Selection is the sole survivor of the age-long theories and hypotheses clustering about evolution. When we consider the youthful zoology and the infantile paleontology of Darwins time (1809-82), our admiration for his genius and marvelous powers of generalization constantly increases. What would his generalizations have risen to with our present knowledge? The ratio of the 8,767 vertebrate species known in his time to the 65,939 species known in 1925, nearly 8 to 1, is about the measure of the biological progress of the first century of evolution. In 1831 only three species of fossil elephants were known-the Mammoth (Eleph-as primnigenius), the Mastodon (Mastodon amerlicanus) and the southern mammoth (Elephas meridionalis); now there are over 350 species and over 30 genera. Darwin foresaw the promised land of paleontology, but did not live to enter it. It is a striking fact that the zoologists, experimentalists and geneticists who, a quarter century ago, were stoutly combatting Wallace, Weismann, and other superselectionists, have, one after another, returned to the Darwinian sheepfold and are now almost unanimously teaching their students, as if it were a demonstrated fact, that evolution progresses by the survival of fortuitously adaptive mutations. To the mind of the paleontologist these teachings are pure Darwinism camouflaged in new language. Bateson, founder of the genetic school, is the only one to confess frankly his utter failure to explain the origin of species; few have displayed similar courage.

Close of Jurassic and opening of Cretaceous time in North America

First Symposium A year ago the Paleontological and the Geological Societies united in a symposium on The Close of Cretaceous and Opening of Eocene Time in North America. That symposium brought out very clearly the wide differences of opinion and practice now prevailing among American geologists and paleontologists as to the kinds of evidence on which we must chiefly rely in geologic and paleontologic correlation, chiefly as to the relative criteria of earth movements and of paleontology. Subject of Second Symposium We are now met to discuss the characteristic features of another important period of geologic time, namely, the Jurassic-Cretaceous limits, as they have been defined in Europe from which, it can not be too strongly stated, we must take all our geologic time standards and demarkations. In this connection I would like to repeat the main statement in my address last year: “American events can be dated only by . . .