192 



GREGORY: NOTHARCTUS, AN AMERICAN EOCENE PRIMATE 



Die Linne'sche BegrifFshierarchie ist und bleibt ein unvoUkommenes Mittel, um das natiirliche System der Tiere, d. 

 h. den Stamnibaum, zur Darstellung zu bringen. Da wir sie, aus practischen Griinden, gleichwohl nicht entbehren konnen 

 oder nicht entbehren woUen, soUten wir wenigstens darauf bedacht sein, sie so zu gestalten, dass sie die phylogenetischen 

 Zusammenhange nicht verschleiert und dass sie da, wo diesselben noch nicht klar gelegt sind, der weiteren Forschung 

 moghchst wenig vorgreift. Das heisst mit andern Worten, wir sollten es vermeiden, Rubriken aufzustellen, die sich nicht 

 geniigend motivieren lassen, oder aber Formen umfassen, von denen sich noch gar nicht nachweisen lasst, dass sie der 

 Rubrikdefinition entsprechen. Rubriken dieser Art sind aber sowohl Gregorys Tarsiiformes als Wortmans Anaptomor- 

 phinse, Omoniyni^, Palipopithecini und Neopitliecini, Osborns Mesodonta sowohl als Winges Tarsiida' (Stehlin, 19H), 

 p. 1541). 



The present writer, on the contrary, regards the Linnsean system of classification, with all its imper- 

 fections, as a priceles heritage, an invaluable organ of learning and research. If the entire history of an 

 " Entwicklungsherd " were known it would be possible to record in detail the anatomical characters of 

 the ancestral genera, to trace step by step the divergent modifications among many phyla and to describe 

 fully the final stages of each; but, without the aid of symbols or representative classifications, life would 

 be too short either to complete such a history or to read it; and the prerequisite identifications of the 

 material would be greatly hampered. Palaeontologists, as well as all other investigators, labor under 

 economic and psychological conditions which compel them to use systems of symbols in which a part 

 represents the whole. The Linnsean system is a diagram, an outline, an invaluable mnemonic device, 

 for the purpose of suggesting the more complete concept which the investigator has won for himself and 

 is endeavoring to convey to other minds. More specifically, the functions of the Linnsean system as 

 understood by the present writer are as follows. 



(1) It serves as a preliminary index to the cumulative record of anatomical observations in the liter- 

 ature of the subject. 



(2) It aims to express successive degrees of homological resemblances and divergences between the 

 organisms classified. In general, the nearer they stand in the system, the greater is the number of homo- 

 logical resemblances between them; this, of course, implies that the observer has endeavored to dis- 

 cover and to discount such resemblances as have been produced by convergent evolution. In so far 

 as it succeeds in expressing degrees of homological resemblances and differences, the Linnsean system at 

 the same time symbolizes the degrees of consanguinity or kinship of the creatures thus classified. 



(3) The Linnsean system in its entirety stands in general for the progressive loss of primitive char- 

 acters (expressed in the definitions and diagnostic characters given for each group), as we pass from the 

 more general and inclusi\'e groups to the groups of lower rank, as in this series. 



Vertebrata 

 Amniota 



Mammalia 



Placentaha 

 Primates 



Lemuriformes 

 Lemuridse 



Lemurinse 



Lemur 



L. jnongoz 



This aspect of the Linnsean system is sometimes neglected by those specialists who prefer to raise the 

 groups which they have intensively investigated to higher rank, rather than to keep them in due relation 

 with the more inclusive groups of other investigators. 



