Gar man.] 
180 
[Jan. 16, 
with all the corrugations on the cap, to trace them to their cause 
would be more difficult. As it is, it seems to have inherited the 
peculiarity in the habit of striking, and the possible results, the in- 
clination and the blunted apex of the cap, while the folds are induced 
by the exercise of the habit. From direct observation of captives 
the habit of striking is well known ; it is known also that the re- 
sult of intermittent pressure, of percussion, on the skin of other an- 
imals is to produce thickening and hardening, callosities, corns 
and bunions in cases ; and no reason is known why a similar cause 
• should not produce a similar effect on these snakes. The pressure 
■is applied at the apex of the button. The result is a harder, less 
yielding dermal covering at that point, and the folds are confined 
to the portion least affected by the pounding. With age the shoul- 
ders and constrictions increase in scope. This also is what happens 
on the young rattlesnake. In the latter the change is brought 
about entirely by inheritance ; in the former it is due to the contin- 
uous modifying influence of surroundings exerted during the exis- 
tence of the individual. 
Unless we are prepared to disprove the fact of transmission of the 
effects of such modification from parents to offspring in instances 
like those of the blind fishes and Crustacea, we shall agree that 
lit obtains here. It will be conceded, also, that these effects are 
handed down little by little, and not all at once, until after the ac- 
cumulation has been made. What the young rattlesnake inherits 
irepresents a completed sum of the results of influences such as are 
now making themselves felt on the copperhead. On the cap and 
button of the young of the latter, the effects of a habit modified by 
locality are already apparent ; they become more so as the animal 
grows older. In other phrase, the tendency toward deeper constric- 
tions and higher shoulders is continuous and progressive. Having 
reached a certain degree of development in these respects, more and 
more being transmitted to the progeny in the meanwhile, it is evi- 
dent that on further advance in the same line the shape will become 
.such as to prevent the loss of the cap in sloughing. Of itself this 
'would not provide a rattle ; but the ordinary increase in size of the 
itail, from growth and tumescence, and, possibly, a small amount of 
backward growth of the cap, induced by percussion, serves to dis- 
place the old cap enough to prevent growing the new one entirely 
within it. The similarity in the essential features of a series con- 
structed in this manner to the rattle of the rattlesnake is apparent. 
