No. 580] ORIGIN OF SIX OLE CHARACTERS 



211 



Fourth : while the numerical characters are solely ger- 

 minal, it is difficult or impossible to distinguish both in re- 

 spect to color intensities and to proportions, what is ger- 

 minal, permanent and hereditary from what is somatic or 

 due to environmental and ontogenetic influences. 



These four chief conclusions drawn from the observa- 

 tions of Osgood may now be compared with those inde- 

 pendently obtained by paleontologists. 



3. Likeness and Unlikeness Between Paleontologic and 

 Zoologic Observation 



The mammalian paleontologist observes exactly the 

 same kinds and degrees of characters as the zoologist, 

 namely, very numerous changes of proportion and form, 

 and relatively infrequent numerical changes. In both 

 respects, however, the paleontologist has the very great 

 advantage of observing the extremes and also many of the 

 intermediate stages. 



The chief distinction between these observers is that 

 as the zoologist sees characters they are stationary, he 

 can only infer their separability in movement through his 

 inferences from the comparison of forms like Canis, Alo- 

 pex, and Vulpes, while the paleontologist observes several 

 new evolution properties in these same 1 'characters," 

 namely their actual movement and their relative rate of 

 movement in various lines of descent, as well as their 

 origin and subsequent progression or retrogression, in 

 brief, their phyletic history. Thus the paleontologist is 

 in a position to observe more of the evolution properties 

 in characters of exactly the same kind. Whereas in a 

 series of living forms each character appears to the zool- 



cliaracter appears to the paleontologist-observer as living 

 or dynamic, the life being displayed in what may be called 

 its two movements in a phyletic series. 



The first property of the ontogenetic movement of char- 

 acters in fossils constituted the life work of our great 

 observer Alpheus Hyatt, who proposed the significant and 

 easily recalled terms acceleration and retardation for the 



