VOL. 19, 1933 PALEONTOLOGY: H. F. OSBORN 699 Also , (n - v + a - 2) < (n - v + a - 2) =1~~~n-v =u n-v - n + ca - ) (na"). ( n ) This shows that t4m will be negative for sufficiently large values of m, if ca < 2. 1 In the address delivered at the Chicago meeting of the American Mathematical Society, which is forthcoming in the Bull. Amer. Math. Soc.

ARISTOGENESIS, THE OBSERVED ORDER OF BIOMECHANICAL EVOLUTION* BY HENRY FAIRFIELD OSBORN THE AMERIcAN MUSEUM OF NATURAL HISTORY Read before the Academy, Tuesday, April 25, 1933 The term "biomechanical"1 applies to organic as distinguished from inorganic processes ;2 for example, the evolution of the living invertebrates and vertebrates of the past as observed in paleontology is chiefly recorded in the hard parts of animals formerly full of life. For the observed order of biomechanical adaptation and evolution, which is the subject of the present communication, no fitter, no more apt term can be found than aristogenesis proposed but not defined in my contribution to the "Centenary of Evolution" symposium of the British Association for the Advancement of Science in 1931 and in my last contribution to the National Academy.3 First, the term aristogenesis is derived from the Attic Greek "aristos" (aptufros) signifying "best in its kind," in Euripides referring to warriors, the "best," the "most useful;" in Homer referring to chariots, the "best" or "finest."4 The Greek "genesis" ('yeJ'eaos) from the Aryan base meaning "to produce, bring into being" means "origin, source, birth, descent; .. .mode of formation or production;"' also, in Plato, "an origin, source, productive cause; origination, making (even of common things)."6 Second, the term aristogenesis relates to an actually observed order of nature, a concrete process; it has no theoretic significance such as the "entelechy" of Aristotle, the "pangenesis" of Darwin, the "vitalism" of * This is the ninth contribution on the Origin of Species and the principles of bio- mechanical evolution as demonstrated in paleontology. The numerical references in the present communication are from the complete bibliography in Osborn's "Fifty-Two Years of Research" which will be supplied on application to the Osborn Library. Downloaded by guest on October 1, 2021 700 PALEONTOLOGY: H. F. OSBORN PROC. N. A. S. Driesch, the "bathmism" of Cope, the "emergence" of Morgan, the "holism" of Smuts. It is rather to be compared with the "biogenesis" of Haeckel, a term signifying the recapitulation of ancestral evolution in embryonic and foetal development. Third, aristogenesis as a process of nature is not to be challenged as a concept, still less as an explanation, hypothesis or theory. At present we know how aristogenesis works, we have set forth (Osborn: 874, 901) a series of principles of its operation, but we have no explanation or hy- pothesis to offer as to why it works or what are its causes. In this sense aristogenesis can only be challenged by a reexamination and reinterpreta- tion of the paleontological evidence on which it rests. One principle of this evidence was discovered in the invertebrates by Waagen in 1869, namely, the orderly "W. mutations"7 of the shells of molluscs which arise in a most inconspicuous manner and develop into conspicuous organs. New and amplified principles have been discovered in vertebrates as fully enumerated in my last two communications (Osborn: 874, 901) in this series of biological inductions from my own paleontological researches of the last half century. (See full bibliographic list below.) The evidence for aristogenesis or the direct origin from the geneplasm of biomechanical adaptations is now overwhelming; Waagen's principle of W. mutations in invertebrates (see Osborn: 353) of 1869 was re-dis- covered in 1894 by Osborn (Osborn: 92) in the teeth of vertebrates. It has been confirmed and amplified by researches recorded in fifty-one contributions between the years 1894 and 1933, chiefly based upon thou- sands of independent observations on the evolution of the grinding teeth (Osborn: 33) in the primates, in the equines and proboscideans (teeth), rhinoceroses (teeth and horns), and titanotheres (teeth and horns). These observations are harmonious and concurrent. They have been made purely inductively with no other purpose than the direct recording of facts. Now they enable us to give a clear definition of aristogenesis as follows: Aristogenesis is the gradual, secular, continuous, direct, reactive, adaptive origin of new biomechanisms. It is a creative process from the geneplasm of entirely new germinal characters. It is the orderly creation of something better or more adaptive. Certain lines of descent are distinguished by the potentiality of creative origin from the geneplasm of new adaptive biomecha- nisms. Germinally predetermined origin of new characters tends toward betterment, arises independently, in widely separated geographic areas, at the same or different aristogenic rates. Aristogenesis is a secular genetic and adaptive reaction rather than an immediate adaptive reaction to new habit or environment as in Lamarck's theory. Aristogenes are independent in origin and early development of the Natural Selection principle of Darwin. Fourth, since single new biomechanisms originate in the geneplasm (a term preferable to germ plasm) they may be called "aristogenes" as Downloaded by guest on October 1, 2021 VOL. 19, 1933 PALEONTOLOGY: H. F. OSBORN 701 distinguished from "somatogenes" which originate in the somaplasm. Aristogene is also a better and more distinctive term than "rectigradation," the term first applied (Osborn: 314) to these new biomechanisms. Fifth, aristogenesis, as the direct adaptive origin of new biomechanisms, is of two kinds:

FIGURE 1 Aristogenic evolution from Phiomia osborni to TriJophodon macrogna4hus of the third inferior grinding tooth in the long-jawed mastodons migrating from northern Africa (Phiomia) to southern India (Trilophodon). (a) ARISTOGENES (rectigradations) are governed or predetermined by germinal potentiality in certain lines of racial, specific, generic, family and ordinal descent. The closer the descent or phyletic kinship the more similar are the aristogenes. In extremely close racial lines like that of the Downloaded by guest on October 1, 2021 702 PALEONTOLOGY: H. F. OSBORN PROC. N. A. S. fourteen-million year longirostrine mastodons cited in my last communica- tion to the Academy (Osborn: 901), the aristogenes are closely similar no matter in what part of the world they arise. Thus from 10 aristogenes in the lower Oligocene mastodon (Phiomia osborni of the FayOim of northern Egypt) the number rises to 19 in Trilophodon cooperi also in Trilophodon pontileviensis of the basal Miocene of France and of India, to 20 in the lower Miocene Trilophodon palceindicus, to 25 in the Trilo- phodon chinjiensis of the Punjab and 37 in Trilophodon macrognathus, the two culminating members of this fourteen-million year aristogenic series. (b) ALLOMETRONS are not governed or predetermined by germinal potentiality in certain lines of racial, specific, generic, family and ordinal descent. On the contrary, within species and even within races, for ex- ample the modern species of man Homo sapiens, diverse allometrons or more or less profound changes of proportion, are independently arising. The term allometron (Greek AXXo&os "of another sort or kind, different"8 and yerpov "to measure in any way"'9) signifies changes of proportion or intensity which may be expressed in measurements and indices, for ex- ample the proportional changes of the head expressed in the Greek terms brachycephaly (broad headed), dolichocephaly (long headed), brachyopy (short faced), dolichopy (long faced), bathycephaly (deep skulled), hypsi- cephaly (high skulled), etc., or in the limb proportions brachydactyly (broad fingered), dolichodactyly (long fingered), leptodactyly (slender fingered), dolichopody (long footed), brachiopody (short footed), doli- chomely (long limbed), brachymely (short limbed), etc., or in tooth proportions brachyodonty (short toothed), hypsodonty (long toothed), etc. Allometrons are relatively rapid in development, or temporal, whereas aristogenes are relatively slow, or secular. The causes of geneplasmic allometrons are obscure. In some unknown way they seem to be connected both with hormones, and with the habit inheritance principle of Lamarck and the natural selection principle of Darwin. So far as the modes in which the "origin of species" is defined by bio- mechanisms we are now on absolutely sure ground. This ground is contra- Lamarckian and contra-Darwinian. It is also contrary to the neo-Dar- winian evolutionary hypotheses of the leading biologists and geneticists of our day. BIBLIOGRAPHIC LIST OF THE ORIGIN OF SPECIES SERIES OF PAPERS BY HENRY FARFIELD OSBORN 1. 1925: 649. "The Origin of Species as Revealed by Vertebrate Paleontology," Science, N. S., 61, 23, 24. 1925; 654. "The Origin of Species as Revealed by Vertebrate Paleontology," Nature, 115, 925, 926; 961-963. Downloaded by guest on October 1, 2021 VOL. 19, 1933 PALEONTOLOGY: H. F. OSBORN 703 2. 1925: 672. "The Origin of Species, II-Distinctions between Rectigradations and Allometrons," Proc. Nat. Acad. Sci., 11, 749-752. 3. 1926: 681. "The Origin of Species, 1859-1925," Bull. 1, Peabody Museum of Nat. Hist., 25-38; Scientific Monthly, 22, March, pp. 185-192. 4. 1926: 693. "The Problem of the Origin of Species as It Appeared to Darwin in 1859 and as It Appears to Us Today," Nature, 118, pp. 270-273; Science, N. S., 64, pp. 337-341; (Abstr.) Brit. Assoc. Adv. Sci., Rept. of the Ninety-Fourth Meeting, 1926, p. 359. 4A. 1926: 701. "The Problem of the Origin of Species as It Appeared to Darwin in 1859 and as It Appears Today (a Correction)," Nature, 118, 591, 592. 5. 1927: 714. "The Origin of Species, V-Speciation and Mutation," Amer. Nat., 61, pp. 5-42. 6. 1932: 874. "The Nine Principles of Evolution Revealed by Paleontology," Amer. Naturalist, 66, Jan.-Feb., pp. 52-60. 7. 1931: 870. "New Concept of Evolution Based upon Researches on the Titano- theres and the Proboscideans," Science, N. S., 74, No. 1927, pp. 557-559. 8. 1932: 897. "Biological Inductions from the Evolution of the Proboscidea," Science, Dec. 2, 1932, 76, No. 1979, pp. 501-504. 1933: 901. "Biological Inductions from the Evolution of the Proboscidea," Proc. Nat. Acad. Sci., 19, No. 1, pp. 159-163, January, 1933. 9. 1933: 906. "Aristogenesis, the Oberved Order of Biomechanical Evolution," Nature (in press). (Abstract, with same title, Science, 77, No. 2004, 519.) 10. 1933. "Aristogenesis, the New Inductive Principle of Biomechanical Evolu- tion" (address delivered before the Academie des Sciences, Paris, May 29, 1933). 1 Not found in "The Universal Dictionary of the English Language," edited by Henry Cecil Wyld, London, 1932; or the "Dictionary of Philosophy and Psychology," edited by James Mark Baldwin, New York and London (1901). 2 Osborn, Henry Fairfield, "Biological Inductions from the Evolution of the Pro- boscidea," Proc. Nat. Acad. Sci., 19, No. 1, 159-163 (1933). 8 Idem; also, "The Nine Principles of Evolution Revealed by Paleontology," The Amer. Nat., 66, Jan.-Feb., 52-60 (1932). 4 "A Greek-English Lexicon," compiled by Henry George Liddell and Robert Scott (7th ed.), New York, p. 218 (1883). 6 Wyld, op. cit., 476-477. 6 Liddell and Scott, op. cit., p. 304. As distinguished from the fortuitous "D. mutations" of De Vries. "A Greek-English Lexicon," Liddell and Scott, p. 65. Ibid., p. 956. Downloaded by guest on October 1, 2021