136 The American Naturalist. [March. 
Plate VI. 
Hypertragulus calcaratus Cope, skull, natural size ; from 
the lower Miocene. Fig. i, lower jaw from above, of specimen 
from White River bed of Colorado. Fig. 2, skull from John 
Day series of Oregon ; a, side, b, from above, c, from below. 
Plate VII. 
Bos taiiriis, dentition, two-thirds natural size ; from Cuvier. 
EDITOR'S TABLE. 
The position of the Post-Darwinians is clearly set forth in an 
abstract of a lecture delivered by Prof. E. Ray Lankester, at 
the London Institution, which appears in Nature o{ February, 
28th. Prof. Lankester declares that the error of Lamarck (and 
consequently of the \'eolamarckians, ) consists in the assump- 
tion that acquired characters can be inherited. He says, 
" Congenital variation is an admitted and demonstrable fact ; 
transmission of congenital variations is also an admitted and 
demonstrable fact. Change of structure acquired during life — 
as stated by Lamarck — is also a fact, though very limited. 
But the transmission of these latter changes to offspring is not 
proved experimentally ; all experiment tends to prove that 
they cannot be transmitted." Two inferences may be de- 
rived from these statements. First ; the author of them does 
not believe that the so-called congenital variations can be or 
have been acquired ; second ; that he has no hypothesis to offer 
in explanation of the origin of congenital variations . These 
positions exclude another inference which nevertheless may be 
derived from other propositions embraced in the abstract of 
the lecture. He says, with Lamarck, that " change of structure 
acquired during life is also a fact," and also that " all plants and 
animals produce offspring which resemble their parents on the 
