LAWS OF ORGANIC DEVELOPMENT. : 595 
ment. If, on the other hand, the parents were like those less fully 
grown, then the offspring which have added something have been 
accelerated in their development. 
I claim that a consideration of the uniformity of nature’s 
processes, or inductive reasoning, requires me (however it may 
affect the minds of others) to believe that the groups of species 
whose individuals I have never found to vary, but which differ in 
the same point as those in which I have observed the above va- 
riations, are also derived from common parents, and the more ad- 
vanced have been accelerated or the less advanced retarded, as the 
case may have been with regard to the parents. 
This is not an imaginary case, but a true representation of 
many which have come under my observation. The develop- 
mental resemblances mentioned are universal in the animal and 
probably in the vegetable kingdoms, approaching the exactitude 
above depicted in proportion to the near structural similarity of 
the species considered. 
Example 1.— It is well known that the Cervide of the Old World 
develop a basal snag of the antler (see Cuvier, Ossemens Fossiles, 
and Gray, Cat. British Museum,) at the third year; a majority 
of those of the New World (genera Subulo, Cariacus) never de- 
velop it except in abnormal cases. in the most vigorous maturity 
of the most northern Cariacus (C. Virginianus), while the South 
American Subulo retains to adult age the simple horn or spike of 
. the second year of all Cervide. 
Among the higher Cervide, Rusa and Axis never assume char- 
acters beyond an equivalent of the fourth year of Cervus. In 
Dama the characters are, on the other hand, assumed more rapidly 
than in Cervus, its third year corresponding to the fourth of the 
latter, and the development in after years of a broad plate of 
bone, with points being substituted for the addition of the corres- 
ponding snags, thus commencing another series which terminates 
in the great fossil elk, Megacerus. 
Returning to the American deer we have Blastocerus, whose 
antlers are identical with the fourth year of Cariacus. Corres- 
ponding with the Dama-Megacerus type of the Old World we have 
the moose (Alces) developing the same palmate horn on the basis 
of Cariacus (7. e., without eye-snag. 
Example 2. i select the following series, ais the ma- 
jority of the genera of the North American Helicid 
AMER. NATURALIST, VOL. V. 38 
