18 ■ ELEVENTH REPORT. 



AMERICAN PALEONTOLOGY AND NEO-LAMARCKLS.AL 



E. C. Case. 



The terms Neo-Lamarckism and Neo-Lamarckian Avere fir.st used by 

 Prof. A. A. Packard in 1885 (Introduction to the Standard Natural History.) 

 The foundations of the school were laid before Darwins time in the writings 

 of Lamarck. 



He taught — First, that in animals which have not passed the limit of their 

 development the continued use of an organ increases its size and power 

 and that conversely the lack of use leads to deterioration. Second, that 

 the condition or character thus acquired is transmitted l^y heredity to 

 its offspring. Here Ave have the origin of a variation. Darwin's great 

 work added the factor lacking in Lamarckism and brought a vague hypothesis 

 to the condition of a Avorking principle by elaborating his conception of a 

 Natural Selection. 



It is generally conceded today that Natural Selection can nut originate 

 a variation, the basis of all evolution; but is the dominant factor in the 

 preservation of A'ariations once originated and their deA^elopment into species. 



Lester Ward in an address before the Biological Society of Washington, 

 in 1891 makes the union of these tAA'o principles the basis. of the Neo-Lam- 

 arckian School. He said, '' Neo-Lamarckism, as I understand it. Avhile 

 recognizing natural selection as the more prominent of the two agencies, 

 also recognizes that the increments of change impressed on individuals 

 during their lifetime or brought al^out by indi\ddual efforts or habits ai'e also 

 perpetuated in some measure through heredity and form an important factor 

 in the general process of organic deA'elopment." 



As Avill be shoAvn, the present content of the Neo-Lamarckian idea is not 

 compassed by this definition though it is a clear outgroAA'th therefrom. 



Neo-Lamarckism has received a considerable, if not its chief, Ijody of 

 support from the American paleontologists. This has rather l^een due 

 the conditions AA'hich haA-e presented to them a large body of evidence in 

 a peculiar AA^ay than to the presence of any dominant leader of the movement. 

 The paleontologists of America, and especially those Avorking among A-erte- 

 l^rates haA-e l^een especially fortunate in that they haA-e found almost at 

 their doors large numbers of lieautifulh^ preser\'ed fossils representing long 

 phylogenetic lines and preserved in undisturbed strata, rendering the sequence 

 of the deposition certain. European AA'orkers have not failed in their ap- 

 preciation of the claims of this school but ha\'e rather lacked the same oppor- 

 tunities. 



I take it to be a most significant fact that Avorkers along such diA-ergent 

 lines as fossil vertebrates, fossil invertebrates and fossil leaves, but having 

 in common the opportunity to vieAv long phylogenetic lines should come to a 

 common conclusion. The paleontologist does not have the chance to vieAv 

 large numbers of individuals and so fails to have impressed upon him the 

 frequency of variation; also it is the exception that he can trace the individual 

 A'ariations Avhich are caused by geographical changes, but to compensate 

 for this his material affords him surpassing opportunity for a just appreciation 

 of the influence of time and heredity. The nature of the evidence has in a 

 manner forced the conclusions of the paleontologist and has at the same time 



