259 
Although these laws were given as the result of my own 
observations on Ammonites, I can claim no originality as 
regards the law of earlier inheritance; having, as it happens, 
been anticipated both by Hyatt,* and by Wirtenberger, who 
had also independently arrived at the same conclusions—the 
former from a study of Liassic, the latter from Upper Oolite 
Ammonites. Even they, however, had been forestalled by 
Professor Cope (teste Hyatt). 
It is curious that an extinct group like Ammonites should 
have yielded such important results; but it must be remembered 
that they offer exceptional facilities for the study of 
Heredity. They not only preserved their own ontogenetic 
record in a most complete manner, but they developed very 
quickly, lasted a fairly long time geologically, are very diversi- 
fied in form, and are preserved in considerable numbers in 
- fairly complete sequence. 
The importance, in the origin of species, of the law of 
earlier inheritance which they illustrate will, I hope, become 
apparent from a perusal of this Paper. 
May 31st, 1892. 
PART I.—THE LAWS. 
HeEreEpIty. 
In regard to Heredity the usual formula is “ Like produces 
like.” This is true enough in a general sense; it is decidedly 
' _ untrue ina particular sense. Not only are “sports” of various 
kinds directly contrary to the law that “like produces like ;” 
but, even in homogenesis, the offspring is never exactly like its 
parent was at the same time of life. Neither is it exactly like 
other offspring of the same parent. Nevertheless there is a 
definite tendency on the part of the offspring to exhibit the 
., *In addition to the works to which reference is made in this Paper, I must 
acknowledge my indebtedness to Professor Hyatt’s grand volume, “The Genesis 
of the Arietide ;” Smithsonian Contrib. Knowledge, 1889. 
